Backup Flashcards

Question

Momentum - formula Conservation of momentum - formula Impulse = = Collisions - types & formulae

Answer 1

p = m v sum of initial momentum = sum of final momentum Impulse = F _deltat = _deltap Elastic collision (billiard ball) -\> momentum conserved; kinetic energy conserved Inelastic collision (putty) -\> m₁ v₁ + m₁ v₂ = (m₁ + m₂) v_f

Answer 2

1. theta = arclength / radius radians 2. Torque = F d force x movement arm 3. I = sum m_i r_i² greater when mass further from axis of rotation 4. Torque = moment of inertia x angular acceleration

Answer 3

1. K = 1/2 I w² moment of inertia angular velocity omega 2. W = T x _deltatheta Work = Torque x angular displacement 3. P = Tw Power = Torque x angular velocity 4. L = I w 5. L = p r sin_theta momentum of particle rho x radius x sin.. 6. Yes

Answer 4

the quadrance of two points [A₁=(x₁,y₁)] and [A₂=(x₂,y₂)] in a plane is therefore defined as the sum of squares of differences in the [x] and [y] coordinates: Q(A₁, A₂) = (x₂ - x₁)^2 + (y₂ - y₁)^2

Answer 5

[Wiki page](https://en.wikipedia.org/wiki/Rational_trigonometry#Quadrance)

Answer 6

Hooke's law F = -k x spring constant displacement w = (k/m)^1/2 _Elastic_ potential energy U = 1/2 k x²

Answer 7

w = (g / L)^_1/2

Answer 8

elastic modulus = stress / strain _tensile_ deformation Young's modulus = (F/A) / (_deltaL/L₀) shear modulus = (F/A) / (_deltax/h) bulk modulus = (F/A) / (_deltaV/V)

Answer 9

p = m/V P = F/A P = atmospheric pressure + pgh

Answer 10

F_a/A_a = F_b/A_b hydraulic press

Answer 11

Buoyant force = weight of fluid displaced

Answer 12

volume flux A₁V₁ = A₂V₂ Bernouilli's law P + 1/2pv² + pgy = constant Pressure + Kinetic energy + Potential energy = constant

Answer 13

s p d f s 2 p 6 d 10 f 14 s groups 1 and 2 p groups 3 - 8 d transition elements f lanthanide and actinide series

Answer 14

**STRONG BONDS** 1. Metallic bonds 2. Ionic bonds 3. Covalent bonds **WEAK BONDS** 1. London dispersion forces - induced dipole-induced dipole attraction The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles. London forces are the attractive forces that cause nonpolar substances to condense to liquids and to freeze into solids when the temperature is lowered sufficiently. 2. Dipole-dipole attractions - electrostatic interactions between permanent dipoles in molecules 3. Hydrogen bonds (specially strong form of dipole-dipole) 4. Ion-dipole bonds Bond type Dissociation energy (kcal/mol)[9] Ionic Lattice Energy 250–4000 [10] Covalent Bond Energy 30–260 Hydrogen Bonds 1–12 (about 5 in water) Dipole–Dipole 0.5–2 London Dispersion Forces

Answer 15

The number of molecular orbitals has to equal the number of atomic orbitals. Bringing together two atomic orbitals will always result in two new molecular orbitals, one bonding ("constructive overlap") one antibonding ("destructive overlap") Antibonding orbitals have higher energy than the separated atoms orbitals which in turn have higher energy level than the bonding orbitals. He has a full s shell of two electrons. So when two He atoms bond there are two electrons in the bonding orbital and two in the non bonding orbital. This is a higher energy state than the two separate atoms so they would prefer to be apart.

Answer 16

sigma bond - direct s or p orbital overlap (in line) pi bond - after a sigma bond; p orbital overlap; weaker than sigma

Answer 17

Hybridisation **_is_** the concept of mixing atomic orbitals into new hybrid orbitals (with different energies, shapes, etc., than the component atomic orbitals) suitable for the pairing of electrons to form chemical bonds Hybrid orbitals are very **_useful_** in the explanation of molecular geometry and atomic bonding properties. The amount of p character or s character, which is decided mainly by orbital hybridisation, also can be **_used_** to reliably predict molecular properties such as acidity or basicity

Answer 18

sp - linear - 180^o (the p**_¹_** is implied) sp² - trigonal planar - 120^o sp³ - tetrahedral - 109.5^o

Answer 19

strongest has most s character and least p (similar to why sigma bonds are stronger than pi bonds) 137 Angstroms sp-sp 2p sp-sp² 3p sp-sp³ 4p sp²-sp² 4p sp²-sp³ 5p sp³-sp³ 6p 154 Angstroms

Answer 20

_deltal = a l_{o delta}T alpha is coefficient of linear expansion _deltaA = 2a A_o _deltaT _deltaV = 3a V_{o delta}T

Answer 21

Bond order is the number of chemical bonds between a pair of atoms. For example, in diatomic nitrogen N≡N the bond order is 3, in acetylene H−C≡C−H the bond order between the two carbon atoms is also 3, and the C−H bond order is 1. Bond order gives an indication of the stability of a bond.

Answer 22

Sum surrounding atoms and lone pairs fill as follow s p (1,2 or 3) d....

Answer 23

v = (F / u)^1/2 Tension / mu is mass per unit length v = _{lambda x}f v = (B / p)1/2 Bulk modulus / rho is density

Answer 24

v = (B / p)1/2 Bulk modulus / rho is density loudness in decibels = 10 log₁₀ (I / I_o) Intensity , Io is 10^-12 W/m² Planar waves I = constant Cylindrical waves I = 1/r Spherical waves I = 1/r²

Answer 25

f'= f_o (c +- v_o) / (c +- v_s) speed of wave / observer / source + towards/ - away

Answer 26

standing waves fixed at both ends wavelength_n = 2L / n (n = 1,2,3,4,5...) standing waves fixed at one end e.g tube, wavelength = wavelengthn = 4L / n (n = 1,,3,,5...) [webpage animations](http://www.acs.psu.edu/drussell/Demos/StandingWaves/StandingWaves.html)

Answer 27

f_b = f₁- f₂

Answer 28

Gravitational force F = G m₁ m₂ / r² g = G m / r² Ug = - G m₁m₂ / r

Answer 29

Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun First law - the **Orbital** rule The orbit of a planet is an ellipse with the Sun at one of the two foci. Second law - the **Area** rule A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. Third law - the **Period** rule The **square** of the orbital period of a planet is proportional to the **cube** of the **semi-major axis** of its orbit.

Answer 30

Specific heat c Q = m c _deltaT c joules per gram to raise 1^o Kelvin Molar heat capacity C Q = n C _deltaT C joules per mol to raise 1^o Kelvin

Answer 31

Rate of heat flow (by conduction) **Q/t = K A (_deltaT/_deltax)** K is thermal conductivity of the material _deltax is conductor thickness Stefan's law Rate of heat flow (by radiation) **Q/t = A _{epsilon sigma} T⁴** epsilon is emissivity sigma is Stefan-Boltzmann constant

Answer 32

Hybridization’s crucial exception is this: when an atom that appears to be sp3 hybridized can participate in resonance, that atom is in fact sp2 hybridized. This is because resonance requires an open p-orbital to occur. Sp3 atoms have 4 sp3 -hybridized orbitals but no open p-orbitals, and therefore cannot participate in resonance. Sp2 -hybridized atoms can. Why is it important for resonance to occur? Again, the answer lies in stability. Structures with resonance are more stable than similar structures without resonance, so whenever an atom has an opportunity to free up a p-orbital to accommodate resonance, it will do so. How often will this exception come up? Pretty often. In fact, almost continuously. A note on good practice: When looking for other resonance structures, keep in mind that definite sp3 orbitals (such as a carbon with four bonds) prevent resonance from occurring through them due to their lack of a p-orbital. P-orbitals are like bridges that electrons use as a path for resonance (delocalization). If there is no bridge, the path cannot be traveled.

Answer 33

alkali family - group 1, hydrogen is not a member. good conductors of heat and electricity, most reactive metals, never found in nature uncombined alkaline earth - group 2, also very reactive transition metals - group 3-12, largest group on periodic table, good conductors of heat and electricity, compounds with these elements are usually brightly colored, rare earth elements - Lanthanoids- soft malleable metals, high luster and conductivity Actinoids- radioactive

Answer 34

halogen family - most reactive nonmetals, never found uncombined in nature, halogens combined with metals form salts  noble gases - normally unreactive, also called inert gases,

Answer 35

In an atom with one electron, that electron experiences the full charge of the positive nucleus. In this case, the effective nuclear charge can be calculated from Coulomb's law. However, in an atom with many electrons the outer electrons are simultaneously attracted to the positive nucleus and repelled by the negatively charged electrons. The effective nuclear charge on such an electron is given by the following equation: Zeff = Z - S where Z is the number of protons in the nucleus (atomic number), and S is the average number of electrons between the nucleus and the electron in question (the number of nonvalence electrons).

Answer 36

% Yield = Actual yield / Theoretical yield

Answer 37

Combination A + B -\> C Decomposition C -\> A + B Single displacement A + BC -\> B + AC Double displacement AB + CD -\> AD + CB

Answer 38

1. Lewis dot structure 2. Dash formula - shows the bonds between atoms but not their 3D structure H-C-C.. 3. Condensed formula - CH3CH2... 4. Bond line formula - intersections, corners and endings are assumed to be C unless other drawn in. H not drawn 5. Fischer projection - vertical lines into page, horizontal out of page 6. Newman projection - view straight down axis of one of the sigma bonds. Circle and intersecting lines are C 7. Dash-line-wedge model - wedge out of page, dashed into

Answer 39

1. The longest carbon chain with the most substituents determines the base name 2. The end carbon closest to a carbon with a substituent is always 1 (tie look for next) 3. Any substituent is given the same number as its carbon 4. If the same substituent is used more than once use prefix di-, tri, tetra- ... Order the substituents alphabetically (CH3)2CHCH2CH2Br would be named 1-bromo-3-methylbutane. See organic 1.pdf page 3 (alkanes)

Answer 40

Primary carbons, are carbons attached to one other carbon. (Hydrogens – although usually 3 in number in this case – are ignored in this terminology, as we shall see). Secondary carbons are attached to two other carbons. Tertiary carbons are attached to three other carbons. Finally, quaternary carbons are attached to four other carbons.

Answer 41

Organic Compounds Follow a Similar Naming Pattern Prefix = substituent **3-methyl**hex-2-ene **3-ethyl-2-methyl**hexane First Name = carbon chain number 3-methyl**hex**-2**-**ene 3-ethyl-2-methyl**hex**ane Last Name = type of chain 3-methylhex**-2-ene** 3-ethyl-2-methylhex**ane** Suffix = highest priority functional group 3-methylhex-2-ene 3-ethyl-2-methylhexane If it Sticks Out – It’s a Substituent. These atoms or groups of atoms are considered your substituents, and represent the prefix ‘Miss‘ for Miss Jane Doe. The most common simple substituents include halogens and short carbon chains.

Answer 42

Constitutional isomers are compounds that have the same molecular formula and different connectivity. To determine whether two molecules are constitutional isomers, just count the number of each atom in both molecules and see how the atoms are arranged. If both molecules have the same count for all of the different atoms, and the atoms are arranged in different ways (their connectivity is different), the molecules will be constitutional isomers. (Recall that connectivity means how the atoms are attached to one another. For example, an ether has a connectivity of C-O-C, and analcohol has a connectivity of C-O-H.)

Answer 43

``` meth = 1 eth = 2 prop = 3 but = 4. ``` Pent Hex Sept Oct Non dec = 10

Answer 44

The general formula for an alkane is Cn H2**n+2** The general formula for an alkene is Cn H2**n** The general formula for an alkene is Cn H2**n-2**

Answer 45

In organic chemistry, a saturated compound has **no double or triple bonds**

Answer 46

A Newman projection, useful in alkane stereochemistry, visualizes chemical conformations of a carbon-carbon chemical bond from front to back, with the front carbon represented by a dot and the back carbon as a circle (see below). The front carbon atom is called proximal, while the back atom is called distal. This type of representation is useful for assessing the torsional angle between bonds. useful in **alkane stereochemistry** The purpose of a Newman projection is to show Conformational Isomers (= conformers = rotational isomers) [This is the same molecule, facing different directions] Typical on a C-C bond of a molecule as the sigma bond is free to rotate

Answer 47

Full complement of hydrogens = saturated. In organic chemistry, a **saturated** compound is a chemical compound that has a chain of carbon atoms linked together by **single** bonds. Alkanes are an example of saturated compounds. An **unsaturated** compound is a chemical compound that contains carbon-carbon **double** bonds or **triple** bonds, such as those found in alkenes or alkynes, respectively. Saturated and unsaturated compounds need not consist only of a carbon atom chain. They can form straight chain, branched chain, or ring arrangements. They can have functional groups, as well. *In other unsaturated hydrocarbons, the double bond between two carbons prevents rotation of the atoms about the bond, locking them into specific structural formations. When attached atoms occupy similar positions on each carbon, they are referred to as "cis", and when they are on opposite sides, they are called "trans". Most natural hydrocarbons exist in the cis state, but artificially manufactured hydrocarbons are trans. The body lacks the enzymes to properly break down the trans configuration. This is why trans fats are viewed as dangerous and unhealthy, as they tend to build up. Unsaturated compounds of the two formations are classified as geometric isomers of one another.*

Answer 48

P₁V₁ = P₂V₂ constant temperature V₁/T₁ = V₂/T₂ constant pressure PV = nRT n is mol; R is universal gas constant

Answer 49

Kinetic energy = (3/2) kT k is Boltzmann's constant [webpage LINK](http://ef.engr.utk.edu/hyperphysics/hbase/thermo/temper.html) Internal energy U = (3/2) nRT n is mol; R is universal gas constant gas molecule speed proportional to (mass)^-1/2 Important - speed-mass relationship at constant temperature directly predicts **comparative efusion and diffusion rates**

Answer 50

The first law of thermodynamics is a version of the law of **conservation of energy**, adapted for **thermodynamic** systems. The law of conservation of energy states that the **1. total energy of an isolated system is constant**; 2. energy can be transformed from one form to another, but cannot be created or destroyed. The first law is often formulated by stating that the change in the internal energy of a closed system is equal to the amount of heat supplied to the system, minus the amount of work done **by the system** on its surroundings. _deltaU = Q - W

Answer 51

The first law of thermodynamics ΔU=Q+W*_{work done on the system}* 1. Isothermal - Constant temperature and thus constant internal energy, Heat flow is compensated by work ΔU = 0 Q = -W 2. Adiabatic - no heat flow, internal energy change = work performed Q = 0 ΔU = -W 3. Isovolumetric - no work occurs, internal energy change = heat flow W = 0 ΔU = Q 4. Isobaric - Constant pressure W = P ΔV ΔU = Q - P ΔV _{The first law of thermodynamics} _{It is typical for chemistry texts to write the first law as ΔU=Q+W. It is the same law, of course - the thermodynamic expression of the conservation of energy principle. It is just that W is defined as the work done on the system instead of work done by the system.} _{n the context of physics, ΔU=Q-W the common scenario is one of adding heat to a volume of gas and using the expansion of that gas to do work, as in the pushing down of a piston in an internal combustion engine. In the context of chemical reactions and process, it may be more common to deal with situations where work is done on the system rather than by it.}

Answer 52

R-C-C-C is propyl (as normal) **iso**propyl is an **iso**mer of propyl R-C-C-C-C is butyl (as normal) **iso**butyl is an **iso**mer of butyl **sec**butyl - the attached carbon R-C is a **sec**ondary carbon ie has two carbons attached to it (in the substituent) **tert**butyl - the attached carbon R-C is a **tert**iary carbon ie has three carbons attached to it (in the substituent)

Answer 53

**cyclo**pentane **cyclo**hexane 7-methyl-8-(1-methylethyl)**bicyclo[4.3.0]**nonane Start counting carbons at the join (bridgehead). Go all the way round one ring, then the next and finish on any shared carbons (bridge). [this gives the pentane or hexane part] clockwise/anti-clockwise follows the usual rules for closest substituent the [**4**. means 4 carbons in the ring 1,2,... the [ .**3**. means 3 carbons in the other ring the .**0**] means no carbons shared by both rings *http://leah4sci.com/organicchemistry/ presents:* *Naming Cycloalkane and Bicyclo alkanes This video is Part 5 in the Naming Organic Compounds series*

Answer 54

Law of **Segregation** - B & b are independently contributed by parents. we have pairs *_{as shown in diagram}* Law of **Independent Assortment** - selection of a particular gene in the gene pair for one trait to be passed to the offspring has nothing to do with the selection of the gene for any other trait. Law of **Dominance** - Some alleles are dominant while others are recessive; an organism with at least one dominant allele will display the effect of the dominant allele. *_{A gamete is a cell that fuses with another cell during fertilization (conception) in organisms that sexually reproduce}* B is dominant gene, b is recessive Mendelian ratio is 3:1

Answer 55

Figure 2 Dihybrid cross. The phenotypes of two independent traits show a **9:3:3:1 (DD, Dr, rD, rr)** ratio in the F2 generation. In this example, coat color is indicated by B (brown, dominant) or b (white), while tail length is indicated by S (short, dominant) or s (long). When parents are homozygous for each trait (SSbb and ssBB), their children in the F1 generation are heterozygous at both loci and only show the dominant phenotypes (SsbB). If the children mate with each other, in the F2 generation all combinations of coat color and tail length occur: 9 are brown/short (purple boxes), 3 are white/short (pink boxes), 3 are brown/long (blue boxes) and 1 is white/long (green box).

Answer 56

genotype = genetic makeup phenotype = expression of a trait dominant trait - expressed in AA Aa aA recessive trait - expressed in aa homozygous = individual having AA or aa heterozygous = individual having aA or Aa allele = A or a *An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.*

Answer 57

Mother is the carrier Son is affected

Answer 58

Diagram then **Kingdoms** - **animals**, plants **Phylum** - **Chordata** (animals with backbone), etc **Class** - **mammalia**, reptilia etc **Order** - **primates**, bats etc **Family** - **hominidae** (humans & great apes), baboons etc **Genus** - **homo**, orangutan, etc **Species** - **homo sapiens**, etc

Answer 59

question stems

Answer 60

**Round-about** - like a politician's answer **Beyond** - relies on information not in the passage ie beyond it **Contrary** - (most answers support the main idea) **Simpleton** - an easily verified bit from the passage that doesn't relate to the question **Unintelligible** - you don't understand the option

Answer 61

**Softeners** - most likely, seemed to, had a tendency to etc

Answer 62

Coulomb's law force between two point charges F = kq₁q₂/r² E = F/q Electric field predicts the force that would exert on a test charge Electric field around a point charge E = kq/r² Gauss's law - Flux through a closed surface = net enclosed electric charge / permittivity of free space

Answer 63

Electrostatic potential energy between two point charges U = kq₁q₂/r

Answer 64

Voltage is the work a field can do on a test charge V = ΔU / q W/A J/C two points in space near a test charge V = kq [1/r_a - 1/r_b] between parallel charged plates V = Ed

Answer 65

[LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 66

Do the compounds have the **same molecular formula** Yes = isomer No = not isomer [LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 67

can the compounds be **interconverted** by **rotation** about a **single** bond Yes = conformational (rotational) isomer (conformer) No = configurational isomer They are both stereoisomers [LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 68

Do the compounds have the **same connectivity** Yes = stereoisomer No = Constitutional (structural) isomer [LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 69

Is the isomerism at a double bond Yes = geometric isomer No = Optical isomer They are both configurational isomers, which is a type of stereoisomer [LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 70

Are the compounds non-superimposable mirror images Yes = enantiomers (an ant in the mirror) No = diastereomers They are both optical isomers, which are a type of configurational isomer, which is a type of stereoisomer [LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 71

same connectivity = steroeisomers No = constitutional isomer [LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 72

same molecular formula = isomer No = not isomer [LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 73

interconverted by rotation about single bonds = conformational isomer No = Configurational isomer [LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 74

[LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 75

[LINK](http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch07/ch7-1.html)

Answer 76

1 mol gas at STP = 22.4L

Answer 77

P_total = P₁ + P₂ ....

Answer 78

**Effusion** is the process in which a gas escapes through a small hole **Diffusion** - is the process by which molecules intermingle as a result of their kinetic energy of random motion. **Rates** are the same for effusion and diffusion - see graphic and beware of **inverse** A A

Answer 79

The Effect of Molecular Orientation on the Reaction of NO and O3. Most collisions of NO and O3 molecules occur with an incorrect orientation for a reaction to occur. Only those collisions in which the N atom of NO collides with one of the terminal O atoms of O3 are likely to produce NO2 and O2, even if the molecules collide with E \> Ea activation energy

Answer 80

reaction rate = **-** Δ [reactants] / Δtime []=concentration reaction rate = + Δ [products] / Δtime k is the rate constant for the forward reaction m is the order of reactant A n is the order of reactant B m + n is the overall order of the reaction *_{see other cards for graphs of the different orders - amount vs time}*

Answer 81

the reaction rate for A is 2 mol/Ls the reaction rate for B is 1.5 mol/Ls the reaction rate for D is 3 mol/Ls [video LINK](https://www.youtube.com/watch?v=oWeDhEidiEo&index=4&list=PLX2gX-ftPVXW5YIBZiWkjf-O-FM7F0a4f)

Answer 82

k = - (slope of reactant concentration with time graph) / [reactant] k does **not** vary within a reaction large k - very steep (big slope) small k - shallow (small slope) [Video webpage LINK](https://www.youtube.com/watch?v=lN5inPpLp7w&list=PLX2gX-ftPVXW5YIBZiWkjf-O-FM7F0a4f&index=5)

Answer 83

**order** of overall reaction = m + n

Answer 84

First order - rate proportional to [reactant] Second order - rate proportional to [reactant]**²** Third order - rate proportional to [reactant]³ *doesn't have to be integer - eg order **1.5** is valid ^1.5*

Answer 85

Experimentally vary the quantity of one reactant (at a time) and see how the reaction rate varies if the rate doubles - order = 1 if the rate x4 - order = 2 if the rate x9 - order = 3 etc

Answer 86

**Activation energy** - the minimum energy which must be available to a chemical system with potential reactants to result in a chemical reaction. Catalyst lowers the activation energy (lower peak)

Answer 87

In chemical kinetics, the overall rate of a reaction is often approximately determined by the **slowest step**, known as the **rate determining step**

Answer 88

In a chemical reaction, **chemical equilibrium** is the state in which both reactants and products are present in concentrations which have **no further tendency to change with time**. Usually, this state results when the forward reaction proceeds at the **same rate** as the reverse reaction. *_{The equilibrium constant is a ratio of the concentration of the products to the concentration of the reactants. If the K value is less than one the reaction will move to the left and if the K value is greater than one the reaction will move to the right}*

Answer 89

**Any change in status quo prompts an opposing reaction in the responding system** When a system at equilibrium is subjected to change in concentration, temperature, volume, or pressure, then the system readjusts itself to (partially) counteract the effect of the applied change and a new equilibrium is established. or whenever a system in equilibrium is disturbed the system will adjust itself in such a way that the effect of the change will be nullified. (in short) This principle has a variety of names, depending upon the discipline using it (see **homeostasis**, a term commonly used in biology). It is common to take Le Châtelier's principle to be a more general observation,[1] roughly stated: In chemistry, the principle is used to manipulate the outcomes of reversible reactions, often to increase the yield of reactions.

Answer 90

what and **can** be **transferred** to the surroundings **Open** - matter and energy **Closed** - energy **Isolated** - nothing

Answer 91

[webpage LINK](http://physics.nist.gov/cuu/pdf/SIDiagramColor.pdf) The **coulomb** is the charge transported by a constant current of **one ampere** in **one second** One **volt** is defined as the difference in electric potential between two points of a conducting wire when an electric current of **one ampere** dissipates **one watt** of power between those points

Answer 92

1. Specific heat is in units of **J/K/kg** , and is the amount of heat needed (in Joules) to raise the temperature of 1 mole of something, by 1 Kelvin (assuming no phase changes). **2. Molar** specific heat is in units of **J/K/mol** , and is the amount of heat needed (in Joules) to raise the temperature of 1 mole of something, by 1 Kelvin (assuming no phase changes).

Answer 93

[webpage LINK](http://wright.nasa.gov/airplane/work2.html)

Answer 94

[webpage LINK](http://labman.phys.utk.edu/phys136/modules/m3/heatpump.htm) [webpage LINK](https://encrypted.google.com/search?q=heat+engine&sa=X&qscrl=1&biw=1920&bih=993&tbm=isch&tbo=u&source=univ&ved=0CFAQsARqFQoTCI6Y17ru-sYCFUErpgodfDQA7g) The Second Law of Thermodynamics states that the state of **entropy** of the entire universe, as an isolated system, will always increase over time. The second law has been expressed in many ways No 100% efficiency _{(a heat engine exhaust gas would have to be 0 Kelvin which is impossible)}

Answer 95

Entropy - a measure of the amount of **energy that is unavailable for work** Entropy - a measure of **disorder** Entropy increases with **dispersal** eg 1. phase change (melting ice), 2. stoichiometric products (if I have more moles after the reaction A + 2B -\> 3C + 2D), 3. increasing gas volume, 4. increasing gas temperature(spreads out)

Answer 96

[webpage LINK](http://kias.dyndns.org/gp/notes/notes.37.html) note the adiabatic _{(no heat energy in or out)}or isothermal _{(no change in temperature)} can go in either direction

Answer 97

**Enthalpy** is defined as a thermodynamic potential, designated by the letter "H", that consists of the internal energy of the system (U) plus the product of pressure (p) and volume (V) of the system: H = U + pV _{Since U, p and V are all functions of the state of the thermodynamic system, enthalpy is a state function.} _{The unit of measurement for enthalpy in the International System of Units (SI) is the joule} In reactions **ΔH** = H_products - H_reactants **Exo**thermic = heat given off H_products reactants **Endo**thermic = heat absorbed H_products \> H_reactants

Answer 98

The total enthalpy change during the complete course of a reaction is the same whether the reaction is made one one step or several steps

Answer 99

Enthalpy of Solution The **heat generated or absorbed when a certain amount of solute is dissolved in a certain amount of solvent.** **Dissolution by most gases is exothermic**. That is, when a gas dissolves in a liquid solvent, energy is released as heat, warming both the system (i.e. the solution) and the surroundings. _{Often the dissolved state is a lower energy state so the excess energy is given off as heat.}

Answer 100

The Gibbs free energy is defined as: G(p,T) = U + pV - TS which is the same as: G(p,T) = H - TS _{where: U is the internal energy (SI unit: joule) p is pressure (SI unit: pascal) V is volume (SI unit: m3) T is the temperature (SI unit: kelvin) S is the entropy (SI unit: joule per kelvin) H is the enthalpy (SI unit: joule)} Gibbs energy is a thermodynamic potential that measures the "**usefulness**" or process-initiating **work** obtainable from a thermodynamic system at a constant temperature and pressure (isothermal, isobaric). _{Just as in mechanics, where potential energy is defined as capacity to do work, similarly different potentials have different meanings. The Gibbs free energy (SI units kJ/mol) is the maximum amount of non-expansion work that can be extracted from a thermodynamically closed system (one that can exchange heat and work with its surroundings, but not matter); this maximum can be attained only in a completely reversible process. When a system changes from a well-defined initial state to a well-defined final state, the Gibbs free energy change ΔP equals the work exchanged by the system with its surroundings, minus the work of the pressure forces, during a reversible transformation of the system from the initial state to the final state.} Gibbs energy is also the chemical potential that is **minimized** when a system reaches **equilibrium** at constant pressure and temperature. _{Its derivative with respect to the reaction coordinate of the system vanishes at the equilibrium point. As such, it is a convenient criterion for the spontaneity of processes with constant pressure and temperature.}

Answer 101

G G = 0 equilibrium G \> 0 Not spontaneous (needs a bit of energy put in to work The Gibbs free energy is defined as: G(p,T) = U + pV - TS which is the same as: G(p,T) = H - TS _{where: U is the internal energy (SI unit: joule) p is pressure (SI unit: pascal) V is volume (SI unit: m3) T is the temperature (SI unit: kelvin) S is the entropy (SI unit: joule per kelvin) H is the enthalpy (SI unit: joule)} Gibbs energy is a thermodynamic potential that measures the "usefulness" or process-initiating work obtainable from a thermodynamic system at a constant temperature and pressure (isothermal, isobaric).

Answer 102

ΔH (exothermic) ΔH \> 0 _{(endothermic)} ΔS \> 0 Spontaneous ΔG at **high** temperature ΔS at **low** temperature **NOT** Spontaneous ΔG\>0 temperature o \> for water freezing / ice melting ΔG = ΔH - TΔS [Video at 2min 50 for explanation if required:](https://www.youtube.com/watch?v=huKBuShAa1w&index=59&list=PLllVwaZQkS2op2kDuFifhStNsS49LAxkZ)

Answer 103

1. Force on a particle with velocity perpendicular to a magnetic field F = q v B sin θ _{[= q(v X B) vector cross]} 2. A particle moving perpendicular to a magnetic field experiences centripital magnetic force leading to uniform circular motion F = qvB = mv²/r _{[sin = 1, solve for r]} 3. Magnetic force on a segment of current carrying conductor F = L I B sin θ _{[L=segment length, I=current, θ= angle between current and magnetic field]} 4. Torque on a current loop within a uniform magnetic field * T* = I A B cos Φ _{^{[A=area of loop, Φ = angle between loop plane and magnetic field]}}

Answer 104

1. Magnetic field on a **straight current carrying wire** B = μ₀ I /( 2 π d) _{[μ0 = permeability of free space; I=current, d=distance from wire]} 2. Magnetic field at the **centre of a current loop**_{[radius r]} B = μ₀ I / (2r) 3. Magnetic field **within a solenoid**_{[n turns per unit length]} B = n μ₀ I [diagram of fields](http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfie.html#c1)

Answer 105

1/f = 1/d_i + 1/d_o M = - d_i/d_o = h_i/h_o

Answer 106

1. Draw a horizontal line from the top of the object to the surface and then through the focal point 2. Draw a line from the top of the object through the focal point Continue the lines, where they cross is the top of the object - shows position and inversion

Answer 107

1. Molarity M = moles of solute / volume of solution 2. Molality m = moles of solute / kg of solvent 3. Mole fraction χ = moles of solute / (total moles of all solutes & solvent) 4. Mass percentage mass % = 100 x mass of solute / total mass of solution 5. ppm = 10⁶ x mass of solute / total mass of solution

Answer 108

1. Molarity M = moles of solute / volume of solution 2. Molality m = moles of solute / kg of solvent 3. Mole fraction χ = moles of solute / (total moles of all solutes & solvent) 4. Mass percentage mass % = 100 x mass of solute / total mass of solution 5. ppm = 10⁶ x mass of solute / total mass of solution

Answer 109

Solubility is a solute's tendency to dissolve in a solvent the maximum moles of the solute that can dissolve in the solution Solubility product K_sp is the equilibrium constant for solvation

Answer 110

1. Solubility of a gas is proportional to the vapour partial pressure so when the can is popped the pressure goes down, so does the solubility of CO₂ gas and the thing fizzes 2. As temperature increase the solubility of gases decreases - so the CO₂ is released from solution and the can explodes

Answer 111

1. An object or a system is chiral if it is distinguishable from its mirror image; that is, it cannot be superposed onto it. _{Conversely, a mirror image of an achiral object, such as a sphere, cannot be distinguished from the object. A chiral object and its mirror image are called enantiomorphs (Greek opposite forms) or, when referring to molecules, enantiomers. A non-chiral object is called achiral (sometimes also amphichiral) and can be superposed on its mirror image.} 2. 3. Chiral centers are tetrahedral atoms (usually carbons) that have four different substituents. 4. Each chiral center in a molecule will be either R or S. 5. As noted above, molecules with a single chiral center are chiral. Molecules with more than one chiral center are usually chiral.

Answer 112

1. An absolute configuration in stereochemistry refers to the **spatial arrangement** of the **atoms** of a **chiral** molecular entity (or group) and its stereochemical description 2. e.g. R or S, referring to **Rectus** _(clockwise), or **Sinister** _{(anti-clockwise)}, respectively. 3. In order to be able to exist as a pair of **enantiomers**, a molecule requires the presence of a chirality center

Answer 113

1. Assign priority _{(by atomic number, highest =1)} to the four attached atoms _{(only those directly attached to the sterecentre)} 2. if there is a tie write out the 3 atoms that the tying atoms are attached to _{(highest of each three first)}. Then use rule 1 to break the tie _{(use the first point of difference, not all three).} 3. If 4 is pointing **into** the page _{(ie on top or bottom)} 123 clockwise=**Rectus**, 123 **anti**clockwise=**Sinister** 4. If 4 is not pointing into the page then apply the single swap rule so that it is. Then apply step 3. The correct configuration is **opposite** to that shown in step 3 _{(the single swap rule reverses Rectus and Sinister)} _{Here’s how it the single swap rule works.} _{Take a molecule with a stereocenter, like (S)-2-butanol (drawn below).} _{If you swap ANY TWO substituents, you will invert the configuration of the stereocenter.} _{That is, switching any two substituents will give you (R)-2-butanol} [webpage LINK](http://www.masterorganicchemistry.com/2011/01/24/the-single-swap-rule/)[Video LINK](https://www.youtube.com/watch?v=8v97XHqYZyc&index=7&list=PL6B957213153CF907)

Answer 114

Here’s how it works. Take a molecule with a stereocenter, like (**S**)-2-butanol (drawn below). If you **swap _ANY_ TWO** substituents, you will **invert the configuration** of the stereocenter. That is, switching any two substituents will give you (**R**)-2-butanol [webpage LINK](http://www.masterorganicchemistry.com/2011/01/24/the-single-swap-rule/) [Video LINK](https://www.youtube.com/watch?v=8v97XHqYZyc&index=7&list=PL6B957213153CF907)

Answer 115

1. **Pure enantiomers** will always **rotate plane-polarized light** to an equal but opposite degree. 2. To establish the **mix of R and S** 3. a racemic mixture is one that has **equal** amounts of left- and right-handed enantiomers of a chiral molecule _{If a stereochemically pure sample of (S)-carvone, for example, rotates plane-polarized light by +10°(clockwise), then a sample of (R)-carvone (in the exact same concentration and under the same experimental conditions) will rotate light by (–)10° (counterclockwise).} _{Chiral molecules have a property known as optical activity: what this means is that a beam of plane-polarized light, when passed through a sample of a chiral substance, will interact with the substance in such a way that the angle of the plane of oscillation will rotate.}

Answer 116

1. **Geometric** isomers _{(diastereometer with double bond)} can be cis or trans 2. **cis = same** side substituents **trans = opposite** side substituents 3. **cis** has a **dipole** moment 4. **cis = higher boiling** point _{(dipole moment gives stronger intermolecular forces)} 5. **cis = lower melting** point _{(poorer symmetry -> poorer crystal forming)} 6. **cis** subtituents **crowd** each other_{(higher energy levels -> higher heat of combustion)}

Answer 117

1. a meso compound is a molecule that has chiral centers but also has an **internal plane of symmetry**. 2. This renders the molecule achiral: it does not have an enantiomer, and it **does not rotate** plane polarized light

Answer 118

1. They show electron movement from one atom to another. 2. Electron moves **from tail** to head(\>) 3. **Own** _{eg a lone pair completely owned by an atom} **Share** _{eg a covalent bond} **Lack** _{eg a lone pair on a completely different atom} 4. **One step at a time** Own Share Lack

Answer 119

[Image LINK](http://www2.trincoll.edu/~tmitzel/chem211fold/classnotes/1029_mon/1029_mon_files/image028.png) [Image LINK](http://www.nptel.ac.in/courses/104103071/module8/lec22/images/v10.jpg)

Answer 120

1. **Ether** - **alkoxy - ane** 2. Aldehyde -formyl -al (-carbaldehyde) 3. Ketone -oxo -one 4. Ester (R)-oxycarbonyl -oate 5. Anhydride -oic \*\* -anhydride 6. Epoxide -epoxy -oxide \*\* eg propanoic anhydride _{(for symmetrical)} or propanoic ehtanoic anhydride

Answer 121

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. **Benzene ring -phenyl -benzene** 2. Enol -?? (E) ... -ol 3. Enoloate

Answer 122

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. **Amine -amino -amine** 2. Nitro -nitro -_{(always substituent)} 3. Nitrile -cyano -nitrile 4. Imine -?? -imine 5. Amide -carbonyl -carboxamide(amide) 6. Enamine -?? -??

Answer 123

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 3. Alkyl halide -haloalkyl -ane 4. **Acyl halide -n/a -oyl halide** (2-methylpropan**oyl chloride**)

Answer 124

The emf induced by a changing magnetic flux through a circuit is **directly proportional** to the **time rate of change of the magnetic flux** trhough the circuit

Answer 125

Generator Mechanical work -\> changes magnetic flux -\> induces emf Motor Electical energy -\> changes magnetic flux -\> mechanical work

Answer 126

The polarity of the induced emf is such that the induced current creates a magnetic field that tends to **oppose the change** that produced it

Answer 127

1. A string of ones start with nothing make a stroke call it one. Add one to itself by adding another stroke and so on 2. S(I) = II S(II) = III etc s(n) = n + 1 3. n = m means that all the I in n line up with I in m 4. n

Answer 128

On switch on it takes time for current to reach maximum. The back emf initially opposes the applied voltage

Answer 129

1. The sum of numbers n and m is the combinations of the strings of I n + m IIII + III = IIIIIII 2. n + m = m + n 3. (k + n) + m = k + (n + m)

Answer 130

1. The product of n and m is the Is formed by a copy of m for every I in n (_{repeated addition)} written n x m 2. commutative n x m = m x n 3. associative (k x n) x m = k x (n x m) 4. identity n x I = n 5. distributive k x (n + m) = k x n + k x m

Answer 131

1. Inverse 2. k + m = n k = n - m (if n \> m) 3. n - (m+k) = (n-m) - k n+ (m-k) = (n+m) -k n - (m-k) = (n-m) + k n x (m-k) = n x m - n x k (n-m) x k = n x k - m x k

Answer 132

1. The charges 2. -1 0 +1 3. The tail is on the bond

Answer 133

1. Ether - alkoxy - ane 2. Aldehyde -formyl -al (-carbaldehyde) 3. Ketone -oxo -one 4. Ester (R)-oxycarbonyl -oate 5. Anhydride -oic \*\* -anhydride **6. Epoxide -epoxy -oxide** \*\* eg propanoic anhydride (for symmetrical) or propanoic ehtanoic anhydride

Answer 134

1. Ether - alkoxy - ane 2. Aldehyde -formyl -al (-carbaldehyde) 3. Ketone -oxo -one 4. Ester (R)-oxycarbonyl -oate **5. Anhydride -oic \*\* -anhydride** 6. Epoxide -epoxy -oxide **\*\* eg propanoic anhydride (for symmetrical) or propanoic ehtanoic anhydride**

Answer 135

1. Ether - alkoxy - ane 2. Aldehyde -formyl -al (-carbaldehyde) 3. Ketone -oxo -one 4. **Ester (R)-oxycarbonyl -oate** 5. Anhydride -oic \*\* -anhydride 6. Epoxide -epoxy -oxide \*\* eg propanoic anhydride (for symmetrical) or propanoic ehtanoic anhydride

Answer 136

1. Ether - alkoxy - ane 2. Aldehyde -formyl -al (-carbaldehyde) 3. **Ketone -oxo -one** 4. Ester (R)-oxycarbonyl -oate 5. Anhydride -oic \*\* -anhydride 6. Epoxide -epoxy -oxide \*\* eg propanoic anhydride (for symmetrical) or propanoic ehtanoic anhydride

Answer 137

1. Ether - alkoxy - ane 2. **Aldehyde -formyl -al (-carbaldehyde)** 3. Ketone -oxo -one 4. Ester (R)-oxycarbonyl -oate 5. Anhydride -oic \*\* -anhydride 6. Epoxide -epoxy -oxide \*\* eg propanoic anhydride (for symmetrical) or propanoic ehtanoic anhydride

Answer 138

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. **Alcohol -hydroxy -ol** 2. Carboxylic acid -carboxy -carboxylic acid(-oic acid) 3. Alkane -alkyl -ane 4. Alkene -alkenyl -ene 5. Alkyne -alkynyl -yne

Answer 139

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. Alcohol -hydroxy -ol **2. Carboxylic acid -carboxy -carboxylic acid(-oic acid)** 3. Alkane -alkyl -ane 4. Alkene -alkenyl -ene 5. Alkyne -alkynyl -yne

Answer 140

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. Alcohol -hydroxy -ol 2. Carboxylic acid -carboxy -carboxylic acid(-oic acid) **3. Alkane -alkyl -ane** **4. Alkene -alkenyl -ene** **5. Alkyne -alkynyl -yne**

Answer 141

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. Amine -amino -amine 2. Nitro -nitro -(always substituent) 3. Nitrile -cyano -nitrile 4. Imine -?? -imine 5. Amide -carbonyl -carboxamide(amide) 6. **Enamine -?? -??**

Answer 142

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. Amine -amino -amine 2. Nitro -nitro -(always substituent) 3. Nitrile -cyano -nitrile 4. Imine -?? -imine 5. **Amide -carbonyl -carboxamide(amide)** 6. Enamine -?? -??

Answer 143

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. Amine -amino -amine 2. **Nitro -nitro -(always substituent)** 3. Nitrile -cyano -nitrile 4. Imine -?? -imine 5. Amide -carbonyl -carboxamide(amide) 6. Enamine -?? -??

Answer 144

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. Amine -amino -amine 2. Nitro -nitro -(always substituent) 3. **Nitrile -cyano -nitrile** 4. Imine -?? -imine 5. Amide -carbonyl -carboxamide(amide) 6. Enamine -?? -??

Answer 145

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. Benzene ring -phenyl -benzene 2. **Enol -?? (E) ... -ol** 3. Enoloate

Answer 146

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. Amine -amino -amine 2. Nitro -nitro -(always substituent) 3. Nitrile -cyano -nitrile 4. **Imine -?? -imine** 5. Amide -carbonyl -carboxamide(amide) 6. Enamine -?? -??

Answer 147

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 1. **Sulfide -n/a -sulfide (eg 2-butyl methyl sulfide )**

Answer 148

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 2. **Thiol -mercapto -thiol**

Answer 149

A carbonyl group is a chemically organic functional group composed of a carbon atom double-bonded to an oxygen atom --\> [**C=O**] The **simplest carbonyl groups are aldehydes and ketones** usually attached to another carbon compound. These structures can be found in many aromatic compounds contributing to smell and taste.

Answer 150

1. Coffee cup and bomb 2. Coffee cup - constant pressure Bomb - constant volume

Answer 151

[image LINK](https://craigssenseofwonder.files.wordpress.com/2011/12/phase-diagram.jpg)

Answer 152

1. Colligative properties are the physical changes that result from adding solute to a solvent. Colligative Properties depend on how many solute particles are present as well as the solvent amount, but they do NOT depend on the type of solute particles. 2a. Vapour pressure _{Vapor pressure or equilibrium vapor pressure is the pressure of a vapor in thermodynamic equilibrium with its condensed phases in a closed container. All liquids and solids have a tendency to evaporate into a gaseous form, and all gases have a tendency to condense back to their liquid or solid form.} 2b. Boiling point 2c. Freezing point 2d. Osmotic pressure _{Osmosis is the diffusion of a fluid through a semipermeable membrane. When a semipermeable membrane (animal bladders, skins of fruits and vegetables) separates a solution from a solvent, then only solvent molecules are able to pass through the membrane. The osmotic pressure of a solution is the pressure difference needed to stop the flow of solvent across a semipermeable membrane. The osmotic pressure of a solution is proportional to the molar concentration of the solute particles in solution.}

Answer 153

1. Skeletal, Cardiac, smooth

Answer 154

[image LINK](https://forcefulaction.files.wordpress.com/2013/03/skeletal-muscle-structure.jpg)

Answer 155

[Image LINK](http://www.nature.com/nrm/journal/v12/n6/images/nrm3118-f1.jpg)

Answer 156

[image LINK](http://classes.midlandstech.edu/carterp/Courses/bio210/chap09/Slide25.JPG)

Answer 157

[image LINK](http://www.apsubiology.org/anatomy/2010/2010_Exam_Reviews/Exam_3_Review/18-11_AnatCardMusc.JPG)

Answer 158

[image LINK](http://classes.midlandstech.edu/carterp/Courses/bio210/chap09/210_figure_09_27_labeled.jpg)

Answer 159

**Osteocyte** - maintains bone tissue **Osteoblasts** - forms bone matrix **Osteogenic** cells - stem cell **Osteoclasts** - resorbs bone _{(remove (cells, or a tissue or structure) by gradual breakdown into its component materials and dispersal in the circulation)} [image LINK](https://figures.boundless.com/21211/full/604-bone-cells.jpe) _{Osteogenic cells are the only bone cells that divide.
Osteogenic cells differentiate and develop into osteoblasts which, in turn, are responsible for forming new bone.
Osteoblasts synthesize and secrete a collagen matrix and calcium salts.
When the area surrounding an osteoblast calcifies, the osteoblast becomes trapped and transforms into an osteocyte, the most common and mature type of bone cell.
Osteoclasts, the cells that break down and reabsorb bone, stem from monocytes and macrophages rather than osteogenic cells..
There is a continual balance between osteoblasts generating new bone and osteoclasts breaking down bone.}

Answer 160

[image LINK](http://classes.midlandstech.edu/carterp/Courses/bio210/chap06/Slide3.JPG)

Answer 161

[image LINK](http://intranet.tdmu.edu.ua/data/kafedra/internal/normal_phiz/classes_stud/en/nurse/Bacchaour%20of%20sciences%20in%20nurses/BSN/14%20Physiology%20of%20kidneys.files/image018.jpg)

Answer 162

**Fibrous** This type of joint is **held together by only a ligament**. Examples are where the **teeth** are held to their bony sockets and at both the radioulnar and tibiofibular joints. **Cartilaginous** These joints occur where the connection between the articulating bones is made up of cartilage for example **between vertebrae in the spine** **Synovial** joints are by far the most common classification of joint within the human body. They are highly moveable and all have a **synovial capsule** (collagenous structure) surrounding the entire joint, a **synovial membrane** (the inner layer of the capsule) which secretes synovial fluid (a lubricating liquid) and **cartilage** known as hyaline cartilage which pads the ends of the articulating bones. _{There are 6 types of synovial joints which are classified by the shape of the joint and the movement available}

Answer 163

[image LINK](http://static5.depositphotos.com/1006480/507/v/950/depositphotos_5078000-Diagram-of-the-Human-Skin.jpg)

Answer 164

Functional groups - nomenclature Give the prefix and suffix of the following functional groups 3. **Alkyl halide -haloalkyl -ane** 4. Acyl halide -n/a -oyl halide (2-methylpropanoyl chloride)

Answer 165

1. Groups of cells with related function 2. Muscle, nervous, connective & epithelium

Answer 166

1. As two fluid compartments separated by a plasma membrane 2. Intercellular fluid compartment (2/3) Extracellular fluid compartment (1/3) _{{ECF further broken into Intervascular fluid and interstitial}}

Answer 167

1. The body gets lots of input perturbing the current state. Organs act to get back to the desired conditions. 2. The cells require their surroundings to be within quite narrow bands in order to function 3. ECF (Extra cellular fluid) - maintaining their constiruents relatively constant

Answer 168

A **hydrophilic** molecule or portion of a molecule is one that is typically **charge-polarized** and capable of **hydrogen bonding**, enabling it to dissolve more readily in water than in oil or other hydrophobic solvents. _{Hydrophobicity is the physical property of a molecule (known as a hydrophobe) that is seemingly repelled from a mass of water.[1] (Strictly speaking, there is no repulsive force involved; it is an absence of attraction.)} **Hydrophobic** molecules tend to be **non-polar** and, thus, prefer other neutral molecules and non-polar solvents. Hydrophobic molecules in water often cluster together, forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle. _{Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove non-polar substances from polar compounds}

Answer 169

Non-polar molecules (**hydrophobic**) move across the cell membrane by **simple diffusion** Polar molecules (**hydrophillic**, charged) cannot move across the cell membrane by simple diffusion. **Facilitated diffusion** - They use a transporter protein embedded in the cell membrane that is open to either the ECF or the ICF. Solute enters the opening, the transporter protein changes configuration and allows the solute to the other side.

Answer 170

1. Single transporter - one type of solute 2. Symporter (a co-transporter) - several solutes together. Both must be present and both move in the same direction 3. Antiporter ( a co-transporter) - several solutes together. Both must be present and move in opposite directions.

Answer 171

The transporters are specific to a solute (or several). ie they are NOT general purpose transporters

Answer 172

1. When a channel is open there is a clear hole when closed its gone 2. Ligand - specific chemical to open Voltage - specific gradient across the cell membrane to open Mechanical - specific tension to open

Answer 173

1. From [low] to [high] 2. Pumps always use energy - ATP

Answer 174

1. secondary active transport couples the activity of a co-transporter with a pump 2. They enter the cell together via a symporter the glucose leaves the cell via diffusion the Na+ leaves via an active pump (using ATP) and K+ enters [image LINK](https://classconnection.s3.amazonaws.com/27/flashcards/2060027/jpg/glucose_transport_epithelial_cells1349801502218.jpg)

Answer 175

**Osmosis is the movement of water across membranes** **Aquaporins** selectively conduct water molecules in and out of the cell, while **preventing the passage of ions and other solutes**. Also known as **water channels**, aquaporins are integral membrane pore proteins. Water molecules traverse through the pore of the channel in single file. The presence of water channels increases membrane permeability to water. _{Some of them, known as aquaglyceroporins, also transport other small uncharged solutes, such as glycerol, CO2, ammonia and urea across the membrane, depending on the size of the pore. For example, the aquaporin 3 channel has a pore width of 8-10 Ångströms and allows the passage of hydrophilic molecules ranging between 150-200 Da. However, the water pores are completely impermeable to charged species, such as protons, a property critical for the conservation of the membrane's electrochemical potential difference.[8]}

Answer 176

1. Pure water has the highest concentration of water

Answer 177

Osmosis causes change in compartment size when the membrane is impermeable to the solute eg end up with A say 500mL water and still 2 Na+ ions, B 1.5L water and still 4 Na+ ions

Answer 178

1. Osmolarity = **particles**/L considers ALL molecules Molarity = mol/L 2. 1M NaCl = 2 OsM NaCl because it is Na⁺ Cl^- ions in solution

Answer 179

1. 300 mOsM (milli Osmolars) 2. **iso**smotic 3. **hypo**osmotic 4. **hyper**osmotic

Answer 180

1. #**non**-penetrating molecules/L 2. Osmolarity considers ALL particles, whether they can cross the cell membrane or not 3. Isotonic, nothing 4. hypotonic, water diffuses into the cell causing it to expand 5. hypertonic, water diffuses out of the cell causing it to shrink

Answer 181

1. ICF reducing, ECF oxidising 2. ICF 3. ECF 4. ECF 5. ICF 6. ICF

Answer 182

1. Facilitated diffusion – membrane impermeable molecules can either enter or leave cells using transport proteins. Transport proteins are classified as either transporters or channels. 2. See graph 3. There are only so many transport proteins on the cell surface. So at some concentration they are all being used. So increasing concentration does not increase the flow rate across the cell membrane

Answer 183

1. **Endocrine**: hormone reaches its site of action via the blood circulation. **Neuroendocrine**: hormone is secreted from neurons into the blood to act at a distance 2.**Paracrine**: cytokine is secreted into the interstitial fluid to act locally on target cells. **Autocrine**: cytokine is secreted into interstitial fluid to act on the cell that produced it

Answer 184

Regulate **sodium** and **water** balance Regulate **calcium** balance Regulate **energy** balance Coordinate processes that cope with **stressful** environments Coordinate **growth** and **development**. Coordinate processes associated with **reproduction** and **lactation**.

Answer 185

Hormones are secreted into the blood stream and circulate throughout the body at very low concentrations (**pMolar to nMolar**). Therefore, their rate of production, delivery, and turnover are important control sites

Answer 186

There are three general types of hormone molecules: peptides, steroids, and amines. They differ in their relative solubility in plasma. **Peptide** hormones consist of three or more amino acids and are soluble in blood. **Steroid** hormones are derived from cholesterol and are insoluble in blood. **Amine** hormones are derivatives of amino acids and some are soluble in blood

Answer 187

1. **Peptide** hormones are soluble in blood. They are degraded by the liver and then cleared by the kidney with half-lives of a few minutes. 2. **Steroid** hormones and 3. **thyroid** hormone are not soluble in blood. They circulate bound to protein carriers. Binding to the transport carrier protein extends the half-life of the hormone in the blood (60-90 minutes for steroids, several days for thyroid hormone)

Answer 188

1. The receptor contains a recognition site that binds its hormone with high affinity and selectivity. A cell may express thousands to tens of thousands of receptors for a single hormone

Answer 189

1. The **lipid solubility** of the hormone dictates the cellular location of its receptor. Plasma insoluble hormones bind to intracellular receptors; plasma soluble hormones bind to cell surface receptors 2. **Peptide** hormones bind to cell surface receptors which activate a second messenger (Figure 14). This results in a rapid (seconds) change in function/metabolism. _{Second messengers are important because they provide:} _{Amplification: One hormone molecule can generate thousands of copies of second messenger (e.g., cAMP) and thereby affect many copies of responsive target molecules (effectors) in the cell.} _{Memory: Once activated the second messenger stays on for several seconds to minutes.} _{Complex regulation: Multiple pathways can be initiated by binding one hormone to a single receptor type} 3. 4. **Thyroid** and **steroid** hormones bind to intracellular receptors to activate transcription. This results in synthesis of new proteins and therefore is a slow response

Answer 190

The hormone and its regulated substance do not change independently. By monitoring both the hormone and its regulated substance, one can readily deduce the nature of the dysfunction. When the **target** endocrine gland itself is misbehaving, then it is referred to as a **primary** pathology. If the problem occurs in the **proximal** regulating gland (pituitary), then it is a **secondary** pathology, and those due to the more **distal** regulator (hypothalamus) are **tertiary** pathologies.

Answer 191

1. Natural number NUM: A string of ones. _{Start with nothing make a stroke call it one. Add one to itself by adding another stroke and so on} 2. An INT is an ordered pair of natural numbers written m\n(m less n) _{Integers include 0 and negatives of the natural numbers} 3. Fraction FRA: A fraction is an ordered pair (m,n) of natural numbers m/n 4. Rational number RAT: A Rational number is an ordered pair of Integers a/b (b_not=0) 5. (Rat, +, x) is a field _{[rational numbers, addition, multiplication] (most important field in mathematics)}

Answer 192

[image LINK](https://lh5.googleusercontent.com/R-lDNvNJV7xUvPpUN43rNR-vLiiFVJ1hty2tzZFzIonPNH0qh4LrpVLDeD4qVkL9x-iDMsJ6NbFzTMjN6yQj_STSiqcYO2lLl5V0YkOwS6FrxkKtQD6OHtL7-A)

Answer 193

[image LINK](http://image.tutorvista.com/content/chemical-kinetics/zero-first-second-order-reaction-relationship.gif)

Answer 194

1. There are **more ways** that molecules can collide so they are more likely to do so 2. Increasing the temperature **changes the distribution of velocites.** More will move to a higher velocity and cross the activation energy required for the reaction. _{Reactants need a certain kinetic energy when they collide to break bonds and make the reaction possible. Below this KE they bounce.}

Answer 195

[image LINK](http://chemwiki.ucdavis.edu/@api/deki/files/8513/Arrhenius_Equation.jpg)

Answer 196

[Video webpage image LINK](https://www.boundless.com/chemistry/textbooks/boundless-chemistry-textbook/chemical-equilibrium-14/equilibrium-103/the-equilibrium-constant-434-1858/)

Answer 197

1. Neurons Glial cells (support neurons)

Answer 198

1. The gradient is primarily established by affecting the concentration of three ions in the cell, Na+, Cl- and K+

Answer 199

Equilibrium potentials Due to the concentration gradient of ions across the plasma membrane of cells, the **intracellular fluid has a small excess of negative charge compared to the extracellular fluid**. The separation of charge has the potential to do work. As a result, the magnitude of the charge difference between the inside and outside of the cell is referred to as the membrane potential and measured in millivolts. If there is an excess of negative charges on the inside of the cell, the membrane potential is negative. If the excess charge on the inside of the cell is positive, the membrane potential is positive. The membrane potential of a cell under specific conditions is determined by the concentration of ions inside and outside of the cell and by the permeability of the membrane for those ions

Answer 200

Sn Tin Ag Silver Au Gold Ru Ruthenium Hg Mercury Pb Lead Ba Barium Pt Platinum Pd Palladium U Uranium

Answer 201

HON and the halogens Hydrogen, Oxygen, Nitrogen F Cl Br I

Answer 202

1. Valence shell electron pair repulsion theory 2. The geometries or 3-D shapes of molecules

Answer 203

[Video webpage image LINK](http://www.ontrack-media.net/chemistry/cm3l4rimage5.jpg)

Answer 204

1. The structural formula of a chemical compound is a graphic representation of the molecular structure, showing how the atoms are arranged. _{The chemical bonding within the molecule is also shown, either explicitly or implicitly.} 2. The empirical formula is the simplest formula for a compound. _{A molecular formulais the same as or a multiple of the empirical formula, and is based on the actual number of atoms of each type in the compound. For example, if the empirical formula of a compound is C3H8 , its molecular formulamay be C3H8 , C6H16 , etc.} 3. 4. Diagram

Answer 205

[Video webpage image LINK](http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch10/ch10-6-1.html) [Video webpage image LINK](http://www.chemtube3d.com/orbitalsethene.htm)[Video webpage image LINK](https://classes.yale.edu/CHEM225/studyaids/pericyclic/pericyclic.htm)

Answer 206

1. Aqueous solution only - Arrhenius acid = anything that produces hydrogen ions in aqueous solution base = hydroxide ions 2. Bronsted Lewis acid = anything that donates a proton base = accept 3. Lewis acid = anything that accepts a pair of electrons base = donate _{(most general definition and need to be labelled Lewis acids specifically as they are not generally called acids)}

Answer 207

1. pH = -log[H⁺]

Answer 208

1. Transfer of a proton 2. pH [H⁺]

Answer 209

1. Acids always react with bases so in an equation both sides have acids and bases The LHS reactants are called acid and base The RHS products are called the conjugate acid and conjugate base An acid base reaction involves the donation of a proton (H+) from an acid to a base. The species which loses H+ is the acid The species which gains H+ is the base The conjugate base is what becomes of the acid after it loses H+ The conjugate acid is what becomes of the base after it gains H+

Answer 210

1. The stronger the acid the weaker its conjugate base 2. The stronger the base the weaker its conjugate acid

Answer 211

1. Can act as either an acid or a base depending upon its environment 2. Water

Answer 212

hydroidoic acid HI hydrobromic acid HBr hydrochloric acid HCl Nitric acid HNO₃ Chloric acid HClO₃ perchloric acid HClO₄ Sulfuric acid H₂SO₄

Answer 213

hydride ion H^- amide ion NH₂^- sodium oxide Na₂O calcium oxide CaO sodium hydroxide NaOH potassium hydroxide KOH calcium hydroxide Ca(OH)₂

Answer 214

1. Can donate more than one proton 2. Can donate just two protons

Answer 215

1. More oxygens 2a. the oxygens draw electrons to one side increasing polarity 2b. the oxygens in the conjugate base can share the electrons spreading it over a larger volume thus stabilising the conjugate base

Answer 216

1. **Strength of bond holding hydrogen** to the atom - weaker means more likely to lose so more acidic _{increasing acidity with electronegativity across the table} _{increasing acidity with atom size down the table} 2. **Polarity of the bond** - increasing polarity increases the strength of the acid 3. The key factor in determining acidity is the **stability of the conjugate base.** Any factor which makes the conjugate base more stable will increase the acidity of the acid. Usually, it means stabilizing negative charge since the conjugate base will always be one unit of charge more “negative” than the acid. First, by bringing the charge closer to the positively charged nucleus Second, by spreading charge out over a larger volume _{A conjugate base is what you obtain when you remove a proton (H+) from a compound. For instance, HO(-) is the conjugate base of water. O(2-) is the conjugate base of HO(-). Conversely, conjugate acids are what you obtain when you add a proton to a compound. The conjugate acid of water is H3O(+).}

Answer 217

1. A binary molecule containing hydrogen 2. Acidity increasing left to right; and down

Answer 218

The following equation describes the reaction of water with itself (called autoprotolysis): H2O + H2O H3O+ + OH¯ The equilibrium constant for this reaction is written as follows: Kc = ( [H3O+] [OH¯] ) / ( [H2O] [H2O] ) However, in pure liquid water, [H2O] is a constant value. To demonstrate this, consider 1000 mL of water with a density of 1.00 g/mL. This 1.00 liter (1000 mL) would weigh 1000 grams. This mass divided by the molecular weight of water (18.0152 g/mol) gives 55.5 moles. The "molarity" of this water would then be 55.5 mol / 1.00 liter or 55.5 M. The solutions studied in introductory chemistry are so dilute that the "concentration" of water is unaffected. So 55.5 molar can be considered to be a constant if the solution is dilute enough. Cross-multiplying the above equation gives: Kc [H2O] [H2O] = [H3O+] [OH¯] Since the term Kc [H2O] [H2O] is a constant, let it be symbolized by Kw, giving: **Kw = [H₃O⁺] [OH¯] same as [H⁺] [OH¯]** This constant, Kw, is called the water autoprotolysis constant or water autoionization constant

Answer 219

_{Basic Information} _{1) Weak acids are less than 100% ionized in solution.
2) Acetic acid (formula = HC2H3O2) is the most common weak acid example used by instructors.
3) Another way to write acetic acid's formula is CH3COOH.
4) A common abbreviation for acetic acid is HAc, where Ac¯ refers to the acetate polyatomic ion.} _{The following equation describes the reaction between acetic acid and water:} _{HAc + H2O H3O+ + Ac¯ Note that it is an equilibrium condition.} _{The equilibrium constant for this reaction is written as follows:} _{Kc = ( [H3O+] [Ac¯] ) / ( [HAc] [H2O] )} _{However, in pure liquid water, [H2O] is a constant value. To demonstrate this, consider 1000 mL of water with a density of 1.00 g/mL. This 1.00 liter (1000 mL) would weigh 1000 grams. This mass divided by the molecular weight of water (18.0152 g/mol) gives 55.5 moles. The "molarity" of this water would then be 55.5 mol / 1.00 liter or 55.5 M.} _{The solutions studied in introductory chemistry are so dilute that the "concentration" of water is unaffected. So 55.5 molar can be considered to be a constant if the solution is dilute enough.} _{Moving [H2O] to the other side gives: Kc [H2O] = ( [H3O+] [Ac¯] ) / [HAc]} _{Since the term Kc [H2O] is a constant, let it be symbolized by Ka, giving:} **K_a = ( [H₃O⁺] [Ac¯] ) / [HAc]** This constant, Ka, is called the **acid ionization constant**.

Answer 220

_{Basic Information} _{1) Weak bases are less than 100% ionized in solution.
2) Ammonia (formula = NH3) is the most common weak base example used by instructors.} _{The following equation describes the reaction between ammonia and water:} _{NH3 + H2O NH4+ + OH¯ Note that it is an equilibrium condition.} _{The equilibrium constant for this reaction is written as follows:} _{Kc = ( [NH4+] [OH¯] ) / ( [NH3] [H2O] )} _{However, in pure liquid water, [H2O] is a constant value. To demonstrate this, consider 1000 mL of water with a density of 1.00 g/mL. This 1.00 liter (1000 mL) would weigh 1000 grams. This mass divided by the molecular weight of water (18.0152 g/mol) gives 55.5 moles. The "molarity" of this water would then be 55.5 mol / 1.00 liter or 55.5 M.} _{The solutions studied in introductory chemistry are so dilute that the "concentration" of water is unaffected. So 55.5 molar can be considered to be a constant if the solution is dilute enough.} _{Moving [H2O] to the other side gives: Kc [H2O] = ( [NH4+] [OH¯] ) / [NH3]} _{Since the term Kc [H2O] is a constant, let it be symbolized by Kb, giving:} **K_b = ( [NH₄⁺] [OH¯] ) / [NH₃]** This constant, Kb, is called the **base ionization constant**.

Answer 221

1. The equivalence point, or stoichiometric point, of a chemical reaction is the point at which chemically equivalent quantities of acid and base have been mixed. It can be found by means of an indicator, most often phenolphthalein. _{The equivalence point on the graph is where all of the starting solution (usually an acid) has been neutralized by the titrant (usually a base). It can be calculated precisely by finding the second derivative of the titration curve and computing the points of inflection (where the graph changes concavity);} 2. When a reaction in titration reaches to the half way, at this point the value of equivalence point is termed as half equivalence point. _{For example, the titration of 2M mono protic acid reach to the half-equivalence point when 1 M of the acid has been made into its corresponding base, and 1 M is still left by Stoichiometric.

The half-equivalence point is can be used to determine the acid dissociation and pKa of the acid used in titration. In acid-base titration the ratio between the acid and corresponding base is exactly 1:1 at the half-equivalence point.} [Video webpage image LINK](http://chemistry.tutorvista.com/analytical-chemistry/equivalence-point.html)

Answer 222

1. The endpoint (related to, but not the same as the equivalence point) refers to the point at which the indicator changes color in a colorimetric titration.

Answer 223

1. They will have more than one equivalence point and half equivalence point

Answer 224

1. The freezing point of a solution is **always lower** than that of the pure solvent. 2. The **freezing point depression** is given as ΔT_f = iK_fm where K_f is the molal freezing point depression constant, m is the molality of the solution, and i is the van’t Hoff factor equal to the number of particles the solute dissociates into. For nonelectrolytes, i = 1. For electrolytes, i = number of ions per formula.

Answer 225

**Pi = i M R T** M is molarity R is the gas constant and we will be using the same value as in the gas laws unit: 0.08206 L atm/mol K. i is the van’t Hoff factor equal to the number of particles the solute dissociates into. For nonelectrolytes, i = 1. For electrolytes, i = number of ions per formula. T is the thermodynamic (absolute) temperature _{PV=nRT gives}

Answer 226

1. An afferent neuron has a specialized ending that produces **graded potentials** that can **lead to action potentials** in response to a stimulus.

Answer 227

In other systems such as vision, taste, and hearing, a **specialized receptor cell** produces graded potentials that can trigger an action potential in an afferent neuron

Answer 228

Each afferent neuron receives signals from a **single** type of stimulus.

Answer 229

Frequency of action potentials.

Answer 230

The **skin, muscles, and joints** have receptors that can sense **touch, pressure, temperature, pain, or the position** of the body. The information gathered by these receptors leads to sensations referred to as **somatosensations**. _{Each receptor type responds primarily to only one type of stimulus. Mechanoreceptors are nerve endings that are encapsulated by connective tissue that sense touch and pressure. There are different types of encapsulated nerve endings that have different morphologies which allow them to respond to a specific kind of touch. Stretching of the connective tissue fibers of the encapsulated endings activates ion channels which can produce action potentials that signal to the central nervous system.} _{Posture and movement of body parts are sensed by muscle stretch mechanoreceptors, as well as mechanoreceptors present in skin, joints, tendons, and ligaments. Together they sense the amount of muscle stretch as well as the rate of muscle stretch. Vision and balance also play a role in the perception of where the body is in space, or proprioception.} _{Temperature is sensed in the skin using different types of thermoreceptors. Free nerve endings, which are processes of neurons, sense temperature using ion channels that are activated only at certain temperatures. A single sensory neuron only expresses a single kind of thermoreceptor. Thermoreceptors can also detect certain chemicals. For instance, cold-sensing thermoreceptors respond to menthol, while heat-sensing thermoreceptors respond to capsaicin (from chili peppers) and ethanol.} _{Pain is sensed by free nerve endings expressing nociceptors, which are receptors that sense extreme mechanical deformation, high temperatures, as well as chemicals released by damaged cells or immune cells.}

Answer 231

When light hits the cornea, it is bent, or refracted as it passes from air into the tissue. **This is the largest source of refraction and focusing by the eye** The light continues through the aqueous humor and is refracted as it travels through the lens, which can adjust to focus on objects a certain distance away. **Ciliary muscles** encircle the perimeter of the lens and **flatten the lens when the muscles relax** or **make the lens more round when the muscles contract**. A lens that is more round allows the eye to focus on closer objects.

Answer 232

_{The retina contains two types of photoreceptor cells, the rods and cones. Because the light-sensing portion of the photoreceptor cells faces the back of the retina, the light must travel through several layers of cells before it is detected.} Photopigment proteins (G-protein coupled receptors) in the plasma membrane of the photoreceptors contain **retinal**, a derivative of vitamin A that **changes its conformation in response to a photon of light** (Figure 31). The change in conformation of retinal affects the conformation of the photopigment protein **which starts a signal transduction cascade.** _{The signal transduction cascade reduces the amount of cGMP which causes a cGMP-gated cation channel to close (Figure 31). This hyperpolarizes the photoreceptor cell and eventually results in signaling to the central nervous system}

Answer 233

**Rods** Photoreceptor rod cells express rhodopsin photopigment protein and are **very sensitive to light**. As a result, they are used in **night vision**. **Many** rod photoreceptor cells **bind a single bipolar cell**. This convergence of signals translates into **low resolution vision** during conditions of low illumination **Cones** Photoreceptor cone cells express one of three different photopigment proteins called opsins. Cones are **less sensitive to light** and so are used in conditions of **high levels of illumination**. Bipolar cells bind **only one cone cell** so there is **high resolution vision** with cones. _{The three different opsins that are expressed by the three types of cones bind retinal in unique ways which leads to absorption of light at different wavelengths. The three opsins are sensitive to red, blue or green wavelengths of light. For instance, red light from a red object primarily hyperpolarizes cones expressing red-sensitive opsin. This activates red bipolar cells and ganglion cells. Colors other than red, blue, or green are perceived when combinations of different cones are stimulated. For instance, we perceive yellow when the red and green cones are both stimulated}

Answer 234

Sound transmission The outer ear, which consists of the pinna and external auditory canal, amplify and direct the sound to the middle ear (Figure 32). The middle ear is an air filled cavity with three bones, the malleus, incus, and stapes. The sound hits and deforms the tympanic membrane between the outer and middle ear (Figure 32). The three bones of the middle ear respond to the deformation of the tympanic membrane and amplify the vibration to the oval window on the cochlea of the inner ear. **Because the oval window is much smaller than the tympanic membrane, the vibrations are amplified.** This is important because in the inner ear, fluid is used to transmit the sound

Answer 235

Organ of Corti Within the cochlear duct, sitting on the basilar membrane is the organ of Corti, which contains the hair cells that serve as the receptor cells for sound. Stereocilia of the hair cells are embedded in a tectorial membrane. As the **basilar membrane bounces up and down, the stereocilia bend** (Figure 34). Bending the stereocilia on the hair cells **opens stretch-sensitive K+ channels** and K+ enters the cells due to the composition of the surrounding fluid. K+ entry **depolarizes** the hair cell and **neurotransmitter is released**. Bending in the other direction hyperpolarizes the cell and inhibits neurotransmitter release. After a hair cell activates the afferent neuron, axons from these neurons join to form the cochlear nerve. The region of the basilar membrane along the length of the cochlea that vibrates the most correlates with the frequency of the sound. As a result, the sensation of pitch is determined by which portion of the basilar membrane is activated. The louder the sound, the more vibration and the greater frequency of action potentials produced in the afferent neurons.

Answer 236

_{Organ of Corti} _{Within the cochlear duct, sitting on the basilar membrane is the organ of Corti, which contains the hair cells that serve as the receptor cells for sound.} _{Stereocilia of the hair cells are embedded in a tectorial membrane.} _{As the basilar membrane bounces up and down, the stereocilia bend (Figure 34). Bending the stereocilia on the hair cells opens stretch-sensitive K+ channels and K+ enters the cells due to the composition of the surrounding fluid.} _{K+ entry depolarizes the hair cell and neurotransmitter is released.} _{Bending in the other direction hyperpolarizes the cell and inhibits neurotransmitter release.} _{After a hair cell activates the afferent neuron, axons from these neurons join to form the cochlear nerve.} _{The region of the basilar membrane along the length of the cochlea that vibrates the most correlates with the frequency of the sound.} As a result, the sensation of **pitch is determined by which portion** of the basilar membrane is activated. The **louder** the sound, the more vibration and the **greater frequency of action potentials** produced in the afferent neurons.

Answer 237

The portions of the inner ear that sense movement of the head are called the **vestibular system**. The **semicircular canals** detect rotation of the head while the **otolith** organs detect linear movement of the head

Answer 238

Semicircular canals There are three semicircular canals in the inner ear that allow detection of head rotation along three perpendicular axes – nodding the head, shaking the head, and tipping the ear towards the shoulder (Figure 35). Each canal contains hair cells that move with the head as it rotates around a certain axis. Because **the fluid remains stationary, it bends the steriocilia of the hair cells** which causes **release of neurotransmitter** similar to hair cells of the auditory system.

Answer 239

Otolith organs The otolith organs contain sheets of hair cells that have **calcium carbonate crystals**, called otoliths, embedded in gel that surrounds the stereocilia of the hair cells. Since the otoliths are **heavier than the fluid** around the hair cells, they remain stationary and pull on the stereocilia during linear movements. _{The utricle contains hair cells that point straight up in a standing postion and respond to horizontal linear acceleration.} _{The saccule contains hair cells that are oriented at a 90 degree angle compared to those of the utricle (Figure 35).} _{This allows them to detect up and down motions}

Answer 240

_{Otolith organs} _{The otolith organs contain sheets of hair cells that have calcium carbonate crystals, called otoliths, embedded in gel that surrounds the stereocilia of the hair cells.} _{Since the otoliths are heavier than the fluid around the hair cells, they remain stationary and pull on the stereocilia during linear movements.} The **utricle** contains hair cells that point straight up in a standing postion and respond to horizontal linear acceleration. The **saccule** contains hair cells that are oriented at a 90 degree angle compared to those of the utricle (Figure 35). This allows them to detect up and down motions

Answer 241

TASTE _{Taste ligands dissolved in saliva bind to chemoreceptors on taste buds.} _{Receptor binding raises intracellular Ca++ causing the release of neurotransmitters and producing graded potentials.} _{This leads to the initiation of action potentials in the postsynaptic neuron.} 1. Taste buds can detect chemicals that can be categorized into five different flavors: **sweet, sour, salty, bitter, and umami**. Each type of chemical is detected by different receptors. 2. Each taste bud responds primarily to **one flavor at low concentrations** and **two or three at higher concentrations.**

Answer 242

SMELL Odors in the air are detected by chemoreceptors of olfactory neurons. **1. The olfactory neuron serves as the receptor cell as well as the afferent neuron.** Binding of an odorant receptor leads to activation of signal transduction pathways that open cation channels and lead to graded potentials. Each odorant binds a combination of odorant receptors that are specific for different parts of the molecule. It is the combination of activated receptors that leads to our perception of a smell of a particular substance

Answer 243

SMELL Odors in the air are detected by chemoreceptors of olfactory neurons. The olfactory neuron serves as the receptor cell as well as the afferent neuron. 1**. Binding of an odorant receptor leads to activation of signal transduction pathways that open cation channels and lead to graded potentials.** Each odorant binds a combination of odorant receptors that are specific for different parts of the molecule. It is the combination of activated receptors that leads to our perception of a smell of a particular substance

Answer 244

1. Oxidation is **losing** high energy electrons Oil Rig 2. Reduction is **gaining** high energy electrons

Answer 245

Reduction is a reduction of **charge** | (ie going more negative)

Answer 246

Oxidation is what **oxygen** would have done if it was present so in H₂O hydrogen is oxidised in HF hydrogen is oxidised

Answer 247

The oxidation state rounds up the partial charge and **pretends** that all the bonds are ionic. So you can see where the electrons have gone

Answer 248

**Rule 1: The oxidation number of an element in its free (uncombined) state is zero — for example, Al(s) or Zn(s). O₂** Rule 2: The oxidation number of a monatomic (one-atom) ion = the charge on the ion, for example: Na⁺ = +1 Rule 3: The sum of all oxidation numbers in a neutral compound =zero. The sum of all oxidation numbers in a polyatomic ion = the charge on the ion _{This rule often allows chemists to calculate the oxidation number of an atom that may have multiple oxidation states, if the other atoms in the ion have known oxidation numbers.} Rule 4: The oxidation number of an alkali metal (IA family) in a compound is +1; the oxidation number of an alkaline earth metal (IIA family) in a compound is +2. Rule 5: The oxidation number of oxygen in a compound is usually –2. peroxides (for example, hydrogen peroxide), then the oxygen has an oxidation number of –1. If the oxygen is bonded to fluorine, the number is +1. Rule 6: The oxidation state of hydrogen in a compound is usually +1. If the hydrogen is part of a binary metal hydride (compound of hydrogen and some metal), then the oxidation state of hydrogen is –1. Rule 7: The oxidation number of fluorine is always –1. Chlorine, bromine, and iodine usually have an oxidation number of –1, unless they’re in combination with an oxygen or fluorine.

Answer 249

Rule 1: The oxidation number of an element in its free (uncombined) state is zero — for example, Al(s) or Zn(s). O₂ **Rule 2: The oxidation number of a monatomic (one-atom) ion = the charge on the ion, for example: Na⁺ = +1** Rule 3: The sum of all oxidation numbers in a neutral compound =zero. **The sum of all oxidation numbers in a polyatomic ion = the charge on the ion** _{This rule often allows chemists to calculate the oxidation number of an atom that may have multiple oxidation states, if the other atoms in the ion have known oxidation numbers.} Rule 4: The oxidation number of an alkali metal (IA family) in a compound is +1; the oxidation number of an alkaline earth metal (IIA family) in a compound is +2. Rule 5: The oxidation number of oxygen in a compound is usually –2. peroxides (for example, hydrogen peroxide), then the oxygen has an oxidation number of –1. If the oxygen is bonded to fluorine, the number is +1. Rule 6: The oxidation state of hydrogen in a compound is usually +1. If the hydrogen is part of a binary metal hydride (compound of hydrogen and some metal), then the oxidation state of hydrogen is –1. Rule 7: The oxidation number of fluorine is always –1. Chlorine, bromine, and iodine usually have an oxidation number of –1, unless they’re in combination with an oxygen or fluorine.

Answer 250

Rule 1: The oxidation number of an element in its free (uncombined) state is zero — for example, Al(s) or Zn(s). O₂ Rule 2: The oxidation number of a monatomic (one-atom) ion = the charge on the ion, for example: Na⁺ = +1 **Rule 3: The sum of all oxidation numbers in a neutral compound =zero.** **The sum of all oxidation numbers in a polyatomic ion = the charge on the ion** _{This rule often allows chemists to calculate the oxidation number of an atom that may have multiple oxidation states, if the other atoms in the ion have known oxidation numbers.} Rule 4: The oxidation number of an alkali metal (IA family) in a compound is +1; the oxidation number of an alkaline earth metal (IIA family) in a compound is +2. Rule 5: The oxidation number of oxygen in a compound is usually –2. peroxides (for example, hydrogen peroxide), then the oxygen has an oxidation number of –1. If the oxygen is bonded to fluorine, the number is +1. Rule 6: The oxidation state of hydrogen in a compound is usually +1. If the hydrogen is part of a binary metal hydride (compound of hydrogen and some metal), then the oxidation state of hydrogen is –1. Rule 7: The oxidation number of fluorine is always –1. Chlorine, bromine, and iodine usually have an oxidation number of –1, unless they’re in combination with an oxygen or fluorine.

Answer 251

Rule 1: The oxidation number of an element in its free (uncombined) state is zero — for example, Al(s) or Zn(s). O₂ Rule 2: The oxidation number of a monatomic (one-atom) ion = the charge on the ion, for example: Na⁺ = +1 Rule 3: The sum of all oxidation numbers in a neutral compound =zero. The sum of all oxidation numbers in a polyatomic ion = the charge on the ion _{This rule often allows chemists to calculate the oxidation number of an atom that may have multiple oxidation states, if the other atoms in the ion have known oxidation numbers.} **Rule 4: The oxidation number of an alkali metal (IA family) in a compound is +1;** **the oxidation number of an alkaline earth metal (IIA family) in a compound is +2.** Rule 5: The oxidation number of oxygen in a compound is usually –2. peroxides (for example, hydrogen peroxide), then the oxygen has an oxidation number of –1. If the oxygen is bonded to fluorine, the number is +1. Rule 6: The oxidation state of hydrogen in a compound is usually +1. If the hydrogen is part of a binary metal hydride (compound of hydrogen and some metal), then the oxidation state of hydrogen is –1. Rule 7: The oxidation number of fluorine is always –1. Chlorine, bromine, and iodine usually have an oxidation number of –1, unless they’re in combination with an oxygen or fluorine.

Answer 252

Rule 1: The oxidation number of an element in its free (uncombined) state is zero — for example, Al(s) or Zn(s). O₂ Rule 2: The oxidation number of a monatomic (one-atom) ion = the charge on the ion, for example: Na⁺ = +1 Rule 3: The sum of all oxidation numbers in a neutral compound =zero. The sum of all oxidation numbers in a polyatomic ion = the charge on the ion _{This rule often allows chemists to calculate the oxidation number of an atom that may have multiple oxidation states, if the other atoms in the ion have known oxidation numbers.} Rule 4: The oxidation number of an alkali metal (IA family) in a compound is +1; the oxidation number of an alkaline earth metal (IIA family) in a compound is +2. **Rule 5: The oxidation number of oxygen in a compound is usually –2. peroxides (for example, hydrogen peroxide), then the oxygen has an oxidation number of –1.** **If the oxygen is bonded to fluorine, the number is +1.** Rule 6: The oxidation state of hydrogen in a compound is usually +1. If the hydrogen is part of a binary metal hydride (compound of hydrogen and some metal), then the oxidation state of hydrogen is –1. Rule 7: The oxidation number of fluorine is always –1. Chlorine, bromine, and iodine usually have an oxidation number of –1, unless they’re in combination with an oxygen or fluorine.

Answer 253

Rule 1: The oxidation number of an element in its free (uncombined) state is zero — for example, Al(s) or Zn(s). O₂ Rule 2: The oxidation number of a monatomic (one-atom) ion = the charge on the ion, for example: Na⁺ = +1 Rule 3: The sum of all oxidation numbers in a neutral compound =zero. The sum of all oxidation numbers in a polyatomic ion = the charge on the ion _{This rule often allows chemists to calculate the oxidation number of an atom that may have multiple oxidation states, if the other atoms in the ion have known oxidation numbers.} Rule 4: The oxidation number of an alkali metal (IA family) in a compound is +1; the oxidation number of an alkaline earth metal (IIA family) in a compound is +2. Rule 5: The oxidation number of oxygen in a compound is usually –2. peroxides (for example, hydrogen peroxide), then the oxygen has an oxidation number of –1. If the oxygen is bonded to fluorine, the number is +1. **Rule 6: The oxidation state of hydrogen in a compound is usually +1.** **If the hydrogen is part of a binary metal hydride (compound of hydrogen and some metal), then the oxidation state of hydrogen is –1.** Rule 7: The oxidation number of fluorine is always –1. Chlorine, bromine, and iodine usually have an oxidation number of –1, unless they’re in combination with an oxygen or fluorine.

Answer 254

Rule 1: The oxidation number of an element in its free (uncombined) state is zero — for example, Al(s) or Zn(s). O₂ Rule 2: The oxidation number of a monatomic (one-atom) ion = the charge on the ion, for example: Na⁺ = +1 Rule 3: The sum of all oxidation numbers in a neutral compound =zero. The sum of all oxidation numbers in a polyatomic ion = the charge on the ion _{This rule often allows chemists to calculate the oxidation number of an atom that may have multiple oxidation states, if the other atoms in the ion have known oxidation numbers.} Rule 4: The oxidation number of an alkali metal (IA family) in a compound is +1; the oxidation number of an alkaline earth metal (IIA family) in a compound is +2. Rule 5: The oxidation number of oxygen in a compound is usually –2. peroxides (for example, hydrogen peroxide), then the oxygen has an oxidation number of –1. If the oxygen is bonded to fluorine, the number is +1. Rule 6: The oxidation state of hydrogen in a compound is usually +1. If the hydrogen is part of a binary metal hydride (compound of hydrogen and some metal), then the oxidation state of hydrogen is –1. **Rule 7: The oxidation number of fluorine is always –1. Chlorine, bromine, and iodine usually have an oxidation number of –1, unless they’re in combination with an oxygen or fluorine.**

Answer 255

**Weak** acid and its conjugate base **Weak** base and its conjugate acid _{Key is that there is a substantial amount of acid and base available at equilibrium to soak up any added acid or base}

Answer 256

1. Write the half reactions for Fe⁰ - 2e^- -\> Fe⁺²_{(write it his way!)} 2H⁺ + 2e^- -\> H₂⁰ 2. Fe oxidised by H _OIL 3. H reduced by Fe _RIG 4. Fe is the reducing agent 5. H is the oxidising agent

Answer 257

Cathode is the **+ve** terminal and the **sink** of electrons Anode is the **-ve** terminal and the **source** of electrons [padlet](http://padlet.com/davidofbuderim/esCeKfPVHp)

Answer 258

The salt bridge is viscous (a gel) so would stay in the bridge if only subject to gravity. The Cl_- gets attracted into the +ve Zn side and **keeps the solution neutral** Likewise K₊ to the Cu side As Zn jumps into solution the solution would become more and more positively charged. Eventually the current would stop flowing to the Cu and go back into the Zn solution.

Answer 259

The standard reduction potential is the **tendency for a chemical species to be reduced**, and is measured in **volts** at standard conditions. The more positive the potential is the more likely it will be reduced. It is written in the form of a reduction half reaction. eg Cu²⁺ + 2e^- -\> Cu Standard reduction or oxidation potentials can be determined experimentally using a SHE (standard hydrogen electrode). _{Universally, hydrogen has been recognized as having reduction and oxidation potentials of zero. Therefore, when the standard reduction and oxidation potential of chemical species are measured, it is actually the difference in the potential from hydrogen. By using a galvanic cell in which one side is a SHE, and the other side is half cell of the unknown chemical species, the potential difference from hydrogen can be determined using a voltmeter.} Standard reduction potentials are used to determine the standard cell potential. The standard reduction cell potential and the standard oxidation cell potential can be combined to determine the overall Cell Potentials of a galvanic cell

Answer 260

The standard reduction potential is the tendency for a chemical species to be reduced, and is measured in volts at standard conditions. The more positive the potential is the **more likely it will be reduced.** It is written in the form of a reduction half reaction. eg Cu²⁺ + 2e^- -\> Cu Standard reduction or oxidation potentials can be determined experimentally using a SHE (standard hydrogen electrode). _{Universally, hydrogen has been recognized as having reduction and oxidation potentials of zero. Therefore, when the standard reduction and oxidation potential of chemical species are measured, it is actually the difference in the potential from hydrogen. By using a galvanic cell in which one side is a SHE, and the other side is half cell of the unknown chemical species, the potential difference from hydrogen can be determined using a voltmeter.} Standard reduction potentials are used to determine the standard cell potential. The standard reduction cell potential and the standard oxidation cell potential can be combined to determine the overall Cell Potentials of a galvanic cell

Answer 261

The standard reduction potential is the tendency for a chemical species to be reduced, and is measured in volts at standard conditions. The more positive the potential is the more likely it will be reduced. It is written in the form of a reduction half reaction. eg Cu²⁺ + 2e^- -\> Cu Standard reduction or oxidation potentials can be determined **experimentally** using a SHE (**standard hydrogen electrode**). _{Universally, hydrogen has been recognized as having reduction and oxidation potentials of zero. Therefore, when the standard reduction and oxidation potential of chemical species are measured, it is actually the difference in the potential from hydrogen. By using a galvanic cell in which one side is a SHE, and the other side is half cell of the unknown chemical species, the potential difference from hydrogen can be determined using a voltmeter.} Standard reduction potentials are used to **determine the standard cell potential.** The standard reduction cell potential and the standard oxidation cell potential can be **combined** to determine the overall Cell Potentials of a galvanic cell

Answer 262

ΔG⁰ = -nF E⁰cell nF E^∘cell= RT lnK ΔG⁰ = RT lnK

Answer 263

ΔG⁰ = -nF E⁰_cell The maximum amount of work that can be produced by an electrochemical cell (wmax) is equal to the product of the cell potential (E^∘cell) and the total charge transferred during the reaction (nF = _{moles of electrons x Coulombs per mole of electrons}) The change in free energy (ΔG) is also a measure of the maximum amount of work that can be performed during a chemical process (ΔG = wmax).

Answer 264

**nF E^∘_cell= RT lnK** We can use the relationship between ΔG^∘ and the equilibrium constant K, to obtain a relationship between E^∘cell and K. Recall that for a general reaction of the type aA+bB→cC+dD, the standard free-energy change and the equilibrium constant are related by the following equation: ΔG°=−RTlnK Given the relationship between the standard free-energy change and the standard cell potential ΔG^∘=−nFE^∘_cell , we can write −nFE^∘cell=−RTlnK Rearranging this equation gives above

Answer 265

Unfortunately, these criteria apply only to systems in which all reactants and products are present in their standard states, a situation that is seldom encountered in the real world

Answer 266

The Effect of Concentration on Cell Potential: The Nernst Equation - **arguably the most important relationship in electrochemistry** **nF E_cell= nF E^∘_cell−RT lnQ** Recall that the actual free-energy change for a reaction under nonstandard conditions, ΔG, is given as follows: ΔG=ΔG°+RTlnQ We also know that ΔG = −nFE_cell and ΔG° = −nFE°_cell. Substituting and dividing both sides of this equation by −nF we obtain above

Answer 267

Galvanic cell Reduction at the Cathode Oxidation at the Anode

Answer 268

[electrolytic cell](http://padlet.com/davidofbuderim/esCeKfPVHp)

Answer 269

An [electrolytic cell](http://padlet.com/davidofbuderim/esCeKfPVHp)is a cell which requires an **outside electrical source** to initiate the redox reaction. **The process of how electric energy drives the nonspontaneous reaction is called electrolysis.** Whereas the galvanic cell used a redox reaction to make electrons flow, the electrolytic cell uses electron movement (in the source of electricity) to cause the redox reaction. In an electrolytic cell, electrons are forced to flow in the opposite direction

Answer 270

**Galvanic: turns chemical energy into electrical energy** **Electrolytic Cell: turns electrical energy into chemical energy** The most common form of Electrolytic cell is the rechargeable battery (cell phones, mp3's, etc) or electroplating. While the battery is being used in the device it is a galvanic cell function (using the redox energy to produce electricity). While the battery is charging it is an electrolytic cell function (using outside electricity to reverse the completed redox reaction).

Answer 271

1. A graded potential is a transient change in the membrane potential that decreases in magnitude as it spreads out along the plasma membrane of the neuron and is proportional to the intensity of the stimulus. 2. Graded potentials can stimulate or inhibit neurons and have **no refractory period**, or time period when the cell cannot respond to a stimulus after the first change in potential

Answer 272

1. An action potential is an electrical signal like graded potentials but they differ in several ways. **Action potentials are large changes in membrane potential that have a similar pattern of membrane potential change**. In this way, an action potential is an all-or-none phenomenon because either there is a large change in membrane potential if the stimulus was adequate or there is little change in membrane potential. In addition, action potentials have the same intensity as they travel along a membrane – they **do not diminish over distance**.

Answer 273

At the beginning of an action potential the cell which was at resting membrane potential has a graded potential that causes the membrane to be depolarized If the depolarization from the graded potential reaches a certain voltage, called the **threshold**, then enough voltage-gated Na+ channels will be opened to start an action potential (**stage 2**). Once enough Na+ channels are open, **Na+ starts rushing into** the cell due to the net negative charge inside the cell and the excess of Na+ outside the cell. This causes the membrane potential to increase (stage 2) and **surpass 0 mV** due to the concentration gradient of Na+. The cell is so permeable to Na+ that the membrane potential quickly comes close to the equilibrium potential for Na+. Right before the membrane potential reaches the equilibrium potential for Na+, the Na+ channels inactivate and the slower opening voltage-gated K+ channels open. When the K+ channels open, there is an excess of positive charge and K+ inside the cell (a positive membrane potential) so K+ leaves the cell and travels down its concentration and electrical gradients. This lowers the membrane potential (**stage 3**) and it approaches the equilibrium potential for K+, which is below resting potential (**stage 4**). The K+ channels start to close and the membrane returns to the resting potential (**stage 5**).

Answer 274

1. Once the Na+ channels have inactivated, the membrane must repolarize before the channel returns to the closed state and can be opened again. This means that **there is a refractory period** that prevents another action potential from occurring before the first one has ended. 2. However, because of the refractory period, the action potential travels in **one direction** along the axon and not in two directions. In addition, each action potential that is produced down the axon will be **identical** and will not diminish over time or distance

Answer 275

1. In either case, the graded potentials can start in the dendrites or cell body and if it is strong enough travel to the **axon initial segment,** where the neuron has the highest concentration of voltage-gated ion channels and the lowest threshold, to start an action potential. The initial segment is the beginning of the axon that connects to the neuronal cell body at the axon hillock. 2. Because a neuron can have many dendrites and have many other neurons contacting the dendrites or cell body, the axon hillock and initial segment can **integrate those signals** by requiring that signals reach a **threshold** before an action potential is formed. The **strength**, **frequency** and **location** of a stimulus received by a neuron will determine if threshold is reached because graded potentials are formed, not action potentials.

Answer 276

_{In the human body, axons can be quite long (from the spinal cord to the tip of the toe)}. In order for an action potential to travel quickly along an axon that may be one meter long, **some axons are myelinated**. _{Myelin is an insulator that is made up of many layers of specialized plasma membrane that is formed by Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.} The Schwann cells and oligodendrocytes lay the myelin along the axons with **regularly spaced gaps called nodes of Ranvier**. The myelin speeds conduction along an axon by insulating it and preventing leaking of ions in the area around an action potential. This allows the effects of the action potential, or the change in membrane potential, to be **detected further down the axon** in the neighboring node where there is a concentration of ion channels. In a myelinated axon, the action potential jumps from node to node allowing it to **travel more quickly and more efficiently**

Answer 277

1. **Myelination** and **diameter** (larger is faster) The diameter of an axon also determines how quickly action potentials travel down its length. Larger diameter axons have less resistance so action potentials travel more quickly along their length. This is exploited by the body. Neurons that sense touch have large diameter axons while pain and itch neurons have small diameter axons

Answer 278

Neurons signal to one another through a specialized junction called a **synapse**. _{The synapse is where the electrical signal from one neuron (presynaptic neuron) is transmitted to another neuron (postsynaptic neuron).} Depending on the role of a particular neuron, it can receive signals from many presynaptic neurons (**convergence**) or it can send signals to many postsynaptic neurons (**divergence**). The presynaptic neuron causes a graded potential to occur in the postsynaptic neuron. The graded potential can depolarize the postsynaptic membrane, which makes the potential closer to threshold, and is called an excitatory postsynaptic potential (Figure 26, synapses 1 and 2). Alternatively, the graded potential can hyperpolarize the postsynaptic membrane, which makes the membrane potential farther from threshold, and is called an inhibitory postsynaptic potential (Figure 26, synapse 3). Since presynaptic neurons cause graded potentials in postsynaptic neurons, spatial and temporal summation of signals from multiple synapses can occur so the postsynaptic neuron can integrate information

Answer 279

_{Neurons signal to one another through a specialized junction called a synapse. The synapse is where the electrical signal from one neuron (presynaptic neuron) is transmitted to another neuron (postsynaptic neuron).} Depending on the role of a particular neuron, it can 1. receive signals from many presynaptic neurons **(convergence)** or it can 2. send signals to many postsynaptic neurons **(divergence**). _{The presynaptic neuron causes a graded potential to occur in the postsynaptic neuron. The graded potential can depolarize the postsynaptic membrane, which makes the potential closer to threshold, and is called an excitatory postsynaptic potential (Figure 26, synapses 1 and 2).} _{Alternatively, the graded potential can hyperpolarize the postsynaptic membrane, which makes the membrane potential farther from threshold, and is called an inhibitory postsynaptic potential (Figure 26, synapse 3). Since presynaptic neurons cause graded potentials in postsynaptic neurons, spatial and temporal summation of signals from multiple synapses can occur so the postsynaptic neuron can integrate informationNeuron}

Answer 280

The presynaptic neuron causes a **graded potential** to occur in the postsynaptic neuron. The graded potential can depolarize the postsynaptic membrane, which makes the potential closer to threshold, and is called an excitatory postsynaptic potential (Figure 26, **synapses 1 and 2**). **Alternatively, the graded potential can hyperpolarize** the postsynaptic membrane, which makes the membrane potential farther from threshold, and is called an inhibitory postsynaptic potential (Figure 26, **synapse 3**). Since presynaptic neurons cause graded potentials in postsynaptic neurons, **spatial and temporal summation of signals from multiple synapses** can occur so the postsynaptic neuron can integrate information

Answer 281

_{One example of neurons integrating information is during lateral inhibition of sensory neurons.} In order to discern the exact point of contact of a stimulus such as a pencil, neighboring neurons must be inhibited. For instance in Figure 27, the pencil is depressing the skin so that three sensory neurons are firing. However, the neuron in the middle, neuron 2, is firing more frequently because the pencil is in the middle of its receptive field. Branches from the axons of all three neurons converge on neighboring neurons. However, since neuron 2 is firing action potentials most frequently, its firing is affected the least by the inhibition. Lateral inhibition leads to reduction of the firing of neurons 1 and 3 and the sensation that the pencil is depressing only the field of neuron 2 (Figure 27). This allows for **more precise determination of the stimulus site and type**.

Answer 282

Most synapses in the mammalian nervous system transmit between the presynaptic and postsynaptic neurons using chemicals called **neurotransmitters**. As the action potential from the presynaptic neuron travels to the end of the axon, calcium is released from voltage-gated calcium channels and causes vesicles full of neurotransmitters to fuse with the plasma membrane and dump their contents into the space between the two neurons called the synaptic cleft. The neurotransmitters diffuse across the synaptic cleft and either directly or indirectly activate ion channels on the postsynaptic neuron to cause a graded potential. In an excitatory synapse, ion channels are opened that let positive ions into the cell causing a graded potential that depolarizes the membrane and may or may not be sufficient to reach threshold (excitatory postsynaptic potential). In an inhibitory synapse, chloride enters the cell or potassium leaves the cell causing a graded potential that hyperpolarizes the membrane and moves the membrane potential farther from threshold (inhibitory postsynaptic potential).

Answer 283

Most synapses in the mammalian nervous system transmit between the presynaptic and postsynaptic neurons using chemicals called neurotransmitters. **As the action potential from the presynaptic neuron travels to the end of the axon, calcium is released from voltage-gated calcium channels and causes vesicles full of neurotransmitters to fuse with the plasma membrane and dump their contents into the space between the two neurons called the synaptic cleft.** The neurotransmitters diffuse across the synaptic cleft and either directly or indirectly activate ion channels on the postsynaptic neuron to cause a graded potential. In an excitatory synapse, ion channels are opened that let positive ions into the cell causing a graded potential that depolarizes the membrane and may or may not be sufficient to reach threshold (excitatory postsynaptic potential). In an inhibitory synapse, chloride enters the cell or potassium leaves the cell causing a graded potential that hyperpolarizes the membrane and moves the membrane potential farther from threshold (inhibitory postsynaptic potential).

Answer 284

Most synapses in the mammalian nervous system transmit between the presynaptic and postsynaptic neurons using chemicals called neurotransmitters. As the action potential from the presynaptic neuron travels to the end of the axon, calcium is released from voltage-gated calcium channels and causes vesicles full of neurotransmitters to fuse with the plasma membrane and dump their contents into the space between the two neurons called the synaptic cleft. **The neurotransmitters diffuse across the synaptic cleft and either directly or indirectly activate ion channels on the postsynaptic neuron to cause a graded potential.** In an excitatory synapse, ion channels are opened that let positive ions into the cell causing a graded potential that depolarizes the membrane and may or may not be sufficient to reach threshold (excitatory postsynaptic potential). In an inhibitory synapse, chloride enters the cell or potassium leaves the cell causing a graded potential that hyperpolarizes the membrane and moves the membrane potential farther from threshold (inhibitory postsynaptic potential).

Answer 285

Most synapses in the mammalian nervous system transmit between the presynaptic and postsynaptic neurons using chemicals called neurotransmitters. As the action potential from the presynaptic neuron travels to the end of the axon, calcium is released from voltage-gated calcium channels and causes vesicles full of neurotransmitters to fuse with the plasma membrane and dump their contents into the space between the two neurons called the synaptic cleft. The neurotransmitters diffuse across the synaptic cleft and either directly or indirectly activate ion channels on the postsynaptic neuron to cause a graded potential. **1. An excitatory synapse is a synapse in which an action potential in a presynaptic neuron increases the probability of an action potential occurring in a postsynaptic cell.** **2. In an excitatory synapse, ion channels are opened that let positive ions into the cell causing a graded potential that depolarizes the membrane and may or may not be sufficient to reach threshold (excitatory postsynaptic potential).** In an inhibitory synapse, chloride enters the cell or potassium leaves the cell causing a graded potential that hyperpolarizes the membrane and moves the membrane potential farther from threshold (inhibitory postsynaptic potential).

Answer 286

Most synapses in the mammalian nervous system transmit between the presynaptic and postsynaptic neurons using chemicals called neurotransmitters. As the action potential from the presynaptic neuron travels to the end of the axon, calcium is released from voltage-gated calcium channels and causes vesicles full of neurotransmitters to fuse with the plasma membrane and dump their contents into the space between the two neurons called the synaptic cleft. The neurotransmitters diffuse across the synaptic cleft and either directly or indirectly activate ion channels on the postsynaptic neuron to cause a graded potential. An excitatory synapse is a synapse in which an action potential in a presynaptic neuron increases the probability of an action potential occurring in a postsynaptic cell. In an excitatory synapse, ion channels are opened that let positive ions into the cell causing a graded potential that depolarizes the membrane and may or may not be sufficient to reach threshold (excitatory postsynaptic potential). **1. Inhibitory synapse -A synapse in which an action potential in the presynaptic cell reduces the probability of an action potential occurring in the postsynaptic cell.** **2. In an inhibitory synapse, chloride enters the cell or potassium leaves the cell causing a graded potential that hyperpolarizes the membrane and moves the membrane potential farther from threshold (inhibitory postsynaptic potential).**

Answer 287

The nervous system contains many types of neurotransmitters along with their respective receptors. There are two main types of synapses that are not only found in the central nervous system but also in the periphery. In **cholinergic synapses** the presynaptic neuron releases acetylcholine as the neurotransmitter and it is received by one of two main types of receptors in the postsynaptic neuron or cell. Skeletal muscle and brain express **nicotinic receptors** which are ion channels that are gated by acetylcholine. In heart, smooth muscle and glands, **muscarinic receptors** bind acetylcholine which starts a signal transduction pathway that regulates ion channels. **Adrenergic synapses** release either norepinephrine or epinephrine into the synaptic cleft. The norepinephrine or epinephrine binds to one of two classes of receptors, alpha-adrenergic or beta-adrenergic receptors. Both types of receptors use signal transduction to affect the postsynaptic cell which can be in the heart, smooth muscle, or a gland

Answer 288

**Somatic** motor neurons excite only skeletal muscle and are responsible for most of our voluntary movements. The **enteric** neurons connect to neurons in the wall of the intestinal tract that control many processes there. The **sympathetic and parasympathetic** divisions are important for controlling many processes for body homeostasis The somatic nervous system and autonomic nervous system also differ in their anatomy. In the somatic nervous system, neurons with cell bodies in the central nervous system send axons to the skeletal muscle they innervate. In the autonomic nervous system, a neuron with a cell body in the central nervous system synapses with a second neuron whose cell body is in a ganglion, or cluster of neuronal cell bodies in the periphery. The second neuron sends an axon to the target organ

Answer 289

1. The ganglia for the sympathetic system are for the most part **next to the spinal cord** 2. The ganglia for the parasympathetic system are usually **very close to or within the target organs**.

Answer 290

_{Many organs are innervated by the parasympathetic and sympathetic nerves, or bundles of axons. In most cases this allows one system to activate the organ and the other system to inhibit it.} 1.2. In general, the **parasympathetic** system is activated during periods of **rest or digestion** while the **sympathetic** system is most active during the **fight or flight** situations. _{The sympathetic system prepares us for fighting by increasing the heart rate, releasing glucose from the liver, and dilating our pupils.}In addition, the sympathetic system can divert blood from the skin and digestive system to the heart, brain and skeletal muscles. 3. The **sympathetic** branch of the autonomic nervous system can be thought of as the **gas pedal** on a car while the **parasympathetic** branch is like the **brake**. _{This dual control of systems that cause opposing actions allows for fine control of an organ’s activity and overall body homeostasis.}

Answer 291

1. The boiling point of a solution is **higher(nonvolatile solute)** / **lower (volatile solute)** than that of the pure solvent. 2. The **boilingpoint depression** is given as ΔTf = iK_bm where K**f** is the molal boiling point depression constant, m is the molality of the solution, and i is the van’t Hoff factor equal to the number of particles the solute dissociates into. For nonelectrolytes, i = 1. For electrolytes, i = number of ions per formula.

Answer 292

The efferent portion of the peripheral nervous system consists of the **somatic** nervous system and the **autonomic** nervous system. _{The autonomic nervous system controls the function of glands, smooth muscle, cardiac muscle, and the neurons of the GI tract.} _{It is composed of two neurons in series that can either excite or inhibit the target organ.} _{In contrast, the somatic nervous system contains single neurons that excite skeletal muscles.} _{The movements controlled by the somatic nervous system can be voluntary or involuntary (reflexes)}

Answer 293

The efferent portion of the peripheral nervous system consists of the somatic nervous system and the autonomic nervous system. The **autonomic** nervous system controls the function of **glands, smooth muscle, cardiac muscle, and the neurons of the GI tract**. It is composed of two neurons in series that can either excite or inhibit the target organ. In contrast, the somatic nervous system contains single neurons that excite skeletal muscles. The movements controlled by the somatic nervous system can be voluntary or involuntary (reflexes)

Answer 294

The efferent portion of the peripheral nervous system consists of the somatic nervous system and the autonomic nervous system. The autonomic nervous system controls the function of glands, smooth muscle, cardiac muscle, and the neurons of the GI tract. It is composed of two neurons in series that can either excite or inhibit the target organ. In contrast, the **somatic** nervous system contains **single neurons that excite skeletal muscles.** The movements controlled by the somatic nervous system can be voluntary or involuntary (reflexes)

Answer 295

The axons of motor neurons are myelinated and have large diameters for fast conduction of action potentials. As the axon approaches a skeletal muscle fiber (muscle cell) it usually branches to form synapses with **anywhere from three to one thousand muscle fibers**. _{However, each muscle fiber is usually innervated by only a single neuron.} _{A motor unit consists of a neuron and all of the muscle fibers it innervates.} _{A single neuron innervates fibers from only one muscle and the innervated muscle fibers are usually spread throughout the muscle}

Answer 296

_{The axons of motor neurons are myelinated and have large diameters for fast conduction of action potentials.} _{As the axon approaches a skeletal muscle fiber (muscle cell) it usually branches to form synapses with anywhere from three to one thousand muscle fibers.} _{However, each muscle fiber is usually innervated by only a single neuron.} 1. A motor unit consists of **a neuron and all of the muscle fibers it innervates.** A single neuron innervates fibers from only one muscle and the innervated muscle fibers are usually spread throughout the muscle

Answer 297

The portion of the skeletal muscle fiber plasma membrane that synapses with the motor neuron axon is called the **motor end plate**. Once an action potential arrives at the axon terminal, the depolarization of the membrane opens voltage-gated calcium channels (Figure 36). An increase in intracellular calcium at the terminal causes release of acetylcholine vesicles into the neuromuscular junction. The acetylcholine binds nicotinic channels at the motor end plate which causes them to open and allow sodium to enter (Figure 36). The sodium entry triggers voltage-gated sodium channels near the motor end plate, initiating an action potential which is propagated in all directions along the plasma membrane of the muscle fiber

Answer 298

The portion of the skeletal muscle fiber plasma membrane that synapses with the motor neuron axon is called the motor end plate. 1. Once an action potential arrives at the axon terminal, the depolarization of the membrane opens **voltage-gated calcium channels** (Figure 36). _{An increase in intracellular calcium at the terminal causes release of acetylcholine vesicles into the neuromuscular junction.} _{The acetylcholine binds nicotinic channels at the motor end plate which causes them to open and allow sodium to enter (Figure 36).} _{The sodium entry triggers voltage-gated sodium channels near the motor end plate, initiating an action potential which is propagated in all directions along the plasma membrane of the muscle fiber}

Answer 299

_{The portion of the skeletal muscle fiber plasma membrane that synapses with the motor neuron axon is called the motor end plate.} _{Once an action potential arrives at the axon terminal, the depolarization of the membrane opens voltage-gated calcium channels (Figure 36).} 1. An increase in intracellular calcium at the terminal causes **release of *_acetylcholine vesicles_* into the neuromuscular junction**. The acetylcholine binds nicotinic channels at the motor end plate which causes them to open and allow sodium to enter (Figure 36). The sodium entry triggers voltage-gated sodium channels near the motor end plate, initiating an action potential which is propagated in all directions along the plasma membrane of the muscle fiber

Answer 300

_{The portion of the skeletal muscle fiber plasma membrane that synapses with the motor neuron axon is called the motor end plate.} _{Once an action potential arrives at the axon terminal, the depolarization of the membrane opens voltage-gated calcium channels (Figure 36).} _{An increase in intracellular calcium at the terminal causes release of acetylcholine vesicles into the neuromuscular junction.} 1. The acetylcholine binds **nicotinic channels** at the motor end plate which causes them to **open and allow** **sodium** to enter (Figure 36). The sodium entry triggers voltage-gated sodium channels near the motor end plate, initiating an action potential which is propagated in all directions along the plasma membrane of the muscle fiber

Answer 301

_{The portion of the skeletal muscle fiber plasma membrane that synapses with the motor neuron axon is called the motor end plate.} _{Once an action potential arrives at the axon terminal, the depolarization of the membrane opens voltage-gated calcium channels (Figure 36).} _{An increase in intracellular calcium at the terminal causes release of acetylcholine vesicles into the neuromuscular junction.} _{The acetylcholine binds nicotinic channels at the motor end plate which causes them to open and allow sodium to enter (Figure 36).} 1. The sodium entry triggers **voltage-gated sodium channels** near the motor end plate, initiating an **action potential** which is propagated in all directions along the plasma membrane of the muscle fiber

Answer 302

SPINAL CORD ANATOMY 1. The cell bodies of the neurons that innervate skeletal muscle of the body are found in the **ventral horn of the spinal cord** (Figure 37, blue). _{The neurons that innervate the skeletal muscle of the head are in the brainstem.} _{In the body, sensory signals come into the spinal cord from the dorsal root ganglia, which contain the cell bodies of sensory neurons (Figure 37, red). These neurons can excite motor neurons in the spinal cord.} _{Motor neuron axons travel through tissues as nerves and synapse on skeletal muscle cells.} _{Excitation of motor neurons causes acetylcholine to be released at the neuromuscular junction causing contraction of the muscle. The muscle relaxes when the motor neuron is no longer excited}

Answer 303

SPINAL CORD ANATOMY _{The cell bodies of the neurons that innervate skeletal muscle of the body are found in the ventral horn of the spinal cord (Figure 37, blue).} _{The neurons that innervate the skeletal muscle of the head are in the brainstem.} In the body, sensory signals come into the spinal cord from the **dorsal root ganglia**, which contain the **cell bodies** of sensory neurons (Figure 37, red). These neurons can **excite motor** neurons in the spinal cord. Motor neuron axons travel through tissues as nerves and synapse on skeletal muscle cells. Excitation of motor neurons causes acetylcholine to be released at the neuromuscular junction causing contraction of the muscle. The muscle relaxes when the motor neuron is no longer excited

Answer 304

SPINAL CORD ANATOMY _{The cell bodies of the neurons that innervate skeletal muscle of the body are found in the ventral horn of the spinal cord (Figure 37, blue).} _{The neurons that innervate the skeletal muscle of the head are in the brainstem.} _{In the body, sensory signals come into the spinal cord from the dorsal root ganglia, which contain the cell bodies of sensory neurons (Figure 37, red). These neurons can excite motor neurons in the spinal cord.} _{Motor neuron axons travel through tissues as nerves and synapse on skeletal muscle cells.} Excitation of motor neurons causes **acetylcholine** to be released at the neuromuscular junction causing **contraction** of the muscle. The muscle **relaxes** when the motor neuron is no longer excited

Answer 305

_Two types of lower motor neurons_ The portion of a skeletal muscle that controls **posture** and **movement**, the **extrafusal** muscle fibers, are innervated by **alpha** motor neurons. _{A specialized type of skeletal muscle fiber, the intrafusal muscle cell, resides in the muscle spindle in the interior of the muscle (Figure 38). The intrafusal muscle fibers are innervated by gamma motor neurons.} _{During muscle contraction, alpha and gamma motor neurons are coactivated.} _{Stretching of the intrafusal fibers in the muscle spindle is sensed by stretch receptors and sent via afferent sensory neurons to the spinal cord. This allows for monitoring of the length of the muscle which helps control muscle tone.}

Answer 306

Two types of lower motor neurons _{The portion of a skeletal muscle that controls posture and movement, the extrafusal muscle fibers, are innervated by alpha motor neurons.} _{A specialized type of skeletal muscle fiber, the intrafusal muscle cell, resides in the muscle spindle in the interior of the muscle (Figure 38). The intrafusal muscle fibers are innervated by gamma motor neurons.} During muscle contraction, **alpha and gamma motor neurons** are **coactivated**. S_{tretching of the intrafusal fibers in the muscle spindle is sensed by stretch receptors and sent via afferent sensory neurons to the spinal cord. This allows for monitoring of the length of the muscle which helps control muscle tone.}

Answer 307

Two types of lower motor neurons _{The portion of a skeletal muscle that controls posture and movement, the extrafusal muscle fibers, are innervated by alpha motor neurons.} _{A specialized type of skeletal muscle fiber, the intrafusal muscle cell, resides in the muscle spindle in the interior of the muscle (Figure 38). The intrafusal muscle fibers are innervated by gamma motor neurons.} _{During muscle contraction, alpha and gamma motor neurons are coactivated.} Stretching of the **intrafusal** fibers in the muscle spindle is sensed by stretch receptors and sent via **afferent sensory neurons** to the spinal cord. This allows for monitoring of the **length** of the muscle which helps control muscle tone.

Answer 308

Two types of muscle sensory receptors _{In order for the body to be able to control muscle contraction properly, there must be feedback about the contractile status of individual muscles.} The muscle **spindle** is an important muscle sensory receptor that provides information about muscle **length** and the **rate of change** of muscle length. _{In addition, Golgi tendon organs are encapsulated sensory receptors situated in tendons near the junction with the muscle (Figure 38). They detect changes in muscle tension instead of changes in muscle length.} _{Both types of sensory receptors send information to the spinal cord and the brain that is usually subconscious.}

Answer 309

Two types of muscle sensory receptors _{In order for the body to be able to control muscle contraction properly, there must be feedback about the contractile status of individual muscles.} _{The muscle spindle is an important muscle sensory receptor that provides information about muscle length and the rate of change of muscle length.} In addition, **Golgi tendon organs** are encapsulated sensory receptors situated in tendons near the junction with the muscle (Figure 38). They detect changes in muscle **tension** instead of changes in muscle length. _{Both types of sensory receptors send information to the spinal cord and the brain that is usually subconscious.}

Answer 310

Two types of muscle sensory receptors _{In order for the body to be able to control muscle contraction properly, there must be feedback about the contractile status of individual muscles.} _{The muscle spindle is an important muscle sensory receptor that provides information about muscle length and the rate of change of muscle length.} _{In addition, Golgi tendon organs are encapsulated sensory receptors situated in tendons near the junction with the muscle (Figure 38). They detect changes in muscle tension instead of changes in muscle length.} Both types of sensory receptors send information to the spinal cord and the brain that is usually **subconscious**.

Answer 311

Muscle Stretch Reflex. If a muscle spindle within a muscle is quickly stretched, the **muscle stretch reflex** causes **contraction** of the muscle as well as nearby muscles. This is what occurs when the patellar tendon is struck during a physical exam (Figure 39). _{The afferent sensory neuron relays the stretch signal from the muscle spindle to its cell body in the dorsal root of the spinal cord. The sensory neuron synapses with the motor neuron in the spinal cord that controls that muscle.} _{In addition, the sensory neuron activates an inhibitory neuron which inhibits the motor neuron (reducing its likelihood of firing an action potential) leading to the muscle on the opposite side of the limb, causing it to relax (Figure 39).} _{The muscle spindle reflex is important in allowing maintenance of the length of a certain muscle.}

Answer 312

Muscle Stretch Reflex. _{If a muscle spindle within a muscle is quickly stretched, the muscle stretch reflex causes contraction of the muscle as well as nearby muscles. This is what occurs when the patellar tendon is struck during a physical exam (Figure 39).} The **afferent sensory neuron** relays the stretch signal from the muscle spindle to its cell body in the **dorsal root** of the spinal cord. The sensory neuron synapses with the **motor neuron** in the spinal cord that controls that muscle. I_{n addition, the sensory neuron activates an inhibitory neuron which inhibits the motor neuron (reducing its likelihood of firing an action potential) leading to the muscle on the opposite side of the limb, causing it to relax (Figure 39).} _{The muscle spindle reflex is important in allowing maintenance of the length of a certain muscle.}

Answer 313

Muscle Stretch Reflex. _{If a muscle spindle within a muscle is quickly stretched, the muscle stretch reflex causes contraction of the muscle as well as nearby muscles. This is what occurs when the patellar tendon is struck during a physical exam (Figure 39).} _{The afferent sensory neuron relays the stretch signal from the muscle spindle to its cell body in the dorsal root of the spinal cord. The sensory neuron synapses with the motor neuron in the spinal cord that controls that muscle.} 1. In addition, the sensory neuron activates an **inhibitory neuron which inhibits** the motor neuron (reducing its likelihood of firing an action potential) leading to the muscle on the opposite side of the limb, causing it to relax (Figure 39). 2. The muscle spindle reflex is important in allowing maintenance of the **length** of a certain muscle. **e.g holding a drink**

Answer 314

Golgi Tendon Reflex. 1. If the Golgi tendon organs of a muscle are stretched and stimulated, muscle **contraction** is inhibited through inhibition of the motor neuron leading to that muscle. 2. This is because the afferent neuron activates an **inhibitory** neuron which is synapsing with the **motor** neuron (Figure 40). _{In addition, the opposing muscle is stimulated to contract through the interaction of an excitatory interneuron with the afferent neuron (Figure 40).} _{The Golgi tendon reflex acts to protect muscles and tendons from damage due to excessive tension. In addition, they may play a role in equalizing the load across different parts of a muscle.}

Answer 315

Golgi Tendon Reflex. _{If the Golgi tendon organs of a muscle are stretched and stimulated, muscle contraction is inhibited through inhibition of the motor neuron leading to that muscle.} _{This is because the afferent neuron activates an inhibitory neuron which is synapsing with the motor neuron (Figure 40).} 1. In addition, the opposing muscle is stimulated to contract through the interaction of an **excitatory interneuron** with the afferent neuron (Figure 40). 2. The Golgi tendon reflex acts to **protect** muscles and tendons from damage due to excessive **tension**. _{In addition, they may play a role in equalizing the load across different parts of a muscle.}

Answer 316

Withdrawal Reflexes. _{A withdrawal reflex occurs when a part of the body such as a portion of a limb is subjected to a painful stimulus.} 1. The **flexor** reflex causes contraction of one muscle and relaxation of the opposing muscle to move that portion of the body away from the insult. _{A short time after the flexor reflex initiates, the crossed extensor reflex initiates on the opposite side of the body.} _{This reflex allows for the opposite side of the body to support the body’s weight or to push the body out of the way of the painful stimulus.}

Answer 317

Withdrawal Reflexes. _{A withdrawal reflex occurs when a part of the body such as a portion of a limb is subjected to a painful stimulus.} _{The flexor reflex causes contraction of one muscle and relaxation of the opposing muscle to move that portion of the body away from the insult.} A short time after the flexor reflex initiates, the **crossed extensor reflex** initiates on the **opposite** side of the body. This reflex allows for the opposite side of the body to **support the body’s weight** or to **push the body out of the way** of the painful stimulus.

Answer 318

Locomotion _{Walking and running require the legs to alternate between forward flexion (the swing phase) and backward extension (the stance phase).} _{The repetition of this pattern is synchronized with the other leg so that the two legs remain in opposite phases.} In most animals, if the spinal cord is separated from the brain the four legs can still make coordinated walking motions. This is accomplished through **central pattern generators** which are oscillatory neural circuits of lower motor neurons in the spinal cord. _{Even though these circuits control the basic movements of walking, they are greatly influenced by the brain. For instance, running occurs when the brain causes the central pattern generators to shorten the stance phase.} _{In addition, posture and goal-directed locomotion require input from the brain.} _{However, the central pattern generators allow relatively simple modifications by the brain to control a very complicated process such as locomotion}

Answer 319

_Two types of lower motor neurons_ _{The portion of a skeletal muscle that controls posture and movement, the extrafusal muscle fibers, are innervated by alpha motor neurons.} A specialized type of skeletal muscle fiber, the **intrafusal** muscle cell, resides in the muscle spindle in the interior of the muscle (Figure 38). The intrafusal muscle fibers are innervated by **gamma** motor neurons. _{During muscle contraction, alpha and gamma motor neurons are coactivated.} _{Stretching of the intrafusal fibers in the muscle spindle is sensed by stretch receptors and sent via afferent sensory neurons to the spinal cord. This allows for monitoring of the length of the muscle which helps control muscle tone.}

Answer 320

Two types of muscle sensory receptors _{In order for the body to be able to control muscle contraction properly, there must be feedback about the contractile status of individual muscles.} _{The muscle spindle is an important muscle sensory receptor that provides information about muscle length and the rate of change of muscle length.} In addition, **Golgi tendon organs** are encapsulated sensory receptors situated in tendons near the junction with the muscle (Figure 38). They detect changes in muscle **tension** instead of changes in muscle length. _{Both types of sensory receptors send information to the spinal cord and the brain that is usually subconscious.}

Answer 321

number of motor units activated

Answer 322

increased the number of **myofibrils** in his biceps.

Answer 323

**A contraction** of the biceps and **relaxation** of the triceps

Answer 324

contracted

Answer 325

the low resolution of night vision

Answer 326

the frequency of action potential production

Answer 327

yes, the stimulus required would be greater

Answer 328

both A and B

Answer 329

both A and D

Answer 330

A. myosin ATPase Skeletal muscle fibers are classified into one of three types distinguished by the **speed of their myosin ATPase and preferred metabolism**: fast, glycolytic fibers fatigue quickly fast, oxidative, glycolytic fibers resist fatigue slow, oxidative fibers resist fatigue The main feature of muscle contraction is the interaction of actin, myosin and ATP. [This fundamental process of contraction is regulated by the tropomyosin-troponin-Ca2+ system](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 331

[A. thin filament (actin)](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 332

[B. intracellular organelle that stores calcium ions](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 333

[C. a temporal summation of individual contractions leading to maximal tension.](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 334

A. [Acetylcholinesterase inhibitor slows the removal of acetylcholine thereby increasing receptor occupancy and end plate potentials](http://padlet.com/davidofbuderim/pbszkbg7y942).

Answer 335

B. number of motor units activated and the frequency of their activation.

Answer 336

E. A, B and C A. Cardiac muscle is a striated fiber containing the same arrangements of contractile filaments as skeletal muscle _{Smooth muscle is an involuntary, non-striated type associated with blood vessels and visceral organs} _{Smooth muscle regulates air flow in lungs}

Answer 337

**A. Attachment permits the filament to pull against the cell surface during contraction thereby shortening the entire cell.** Dystrophin is a protein located between the sarcolemma and the outermost layer of myofilaments in the muscle fiber (myofiber). It is a cohesive protein, linking actin filaments to another support protein that resides on the inside surface of each muscle fiber’s plasma membrane (sarcolemma). This support protein on the inside surface of the sarcolemma in turn links to two other consecutive proteins for a total of three linking proteins. The final linking protein is attached to the fibrous endomysium of the entire muscle fiber. **Dystrophin supports muscle fiber strength**, and the **absence of dystrophin reduces muscle stiffness, increases sarcolemmal deformability, and compromises the mechanical stability of costameres and their connections to nearby myofibrils**; as shown in recent studies where biomechanical properties of the sarcolemma and its links through costameres to the contractile apparatus were measured,[5] and helps to prevent muscle fiber injury. **Movement of thin filaments (actin) creates a pulling force on the extracellular connective tissue that eventually becomes the tendon of the muscle.**

Answer 338

[A. Thin filament (actin)](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 339

[B. Thick filaments (myosin)](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 340

[A. Thin filament (actin) only](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 341

[B. Thick filament (myosin)](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 342

[A. I band shortens](http://padlet.com/davidofbuderim/coz0oorilmez) Upon muscle contraction, the A-bands do not change their length (1.85 micrometer in mammalian skeletal muscle), whereas the I-bands and the H-zone shorten

Answer 343

A. Yes. Sarcomeres shorten due to sliding of the thin and thick filaments past each other.

Answer 344

D. A, B, and C

Answer 345

[A. results in sustained contractions](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 346

[A. longer action potential due to slower repolarization](http://padlet.com/davidofbuderim/mrpkwftiahga) Voltage-gated K+ channels (Kv channels), present in all animal cells, open and close upon changes in the transmembrane potential. Kv channels are one of the key components in generation and propagation of electrical impulses in nervous system. Upon changes in transmembrane potential, these channels open and allow passive flow of K+ ions from the cell to **restore the membrane potential**.

Answer 347

[always reach threshold](http://padlet.com/davidofbuderim/4ova3k99hh1l) Pacemaker cells exhibit an unstable resting membrane potential leading to rhythmic states of depolarization followed by repolarization

Answer 348

[kinetics of the myosin ATPase](http://padlet.com/davidofbuderim/4ova3k99hh1l) MYOSIN ATPase has a slow rate of hydrolysis. It hydrolyzes ATP at about 10% of the rate observed in skeletal muscle. Consequently smooth muscle produces slow, sustained contractions using only 10% of the ATP that skeletal muscle would require for the same work

Answer 349

number of cross bridges formed

Answer 350

B. decreased airway resistance in the lung. [myosin light chain kinase -\> activating smooth muscle](http://padlet.com/davidofbuderim/4ova3k99hh1l)

Answer 351

A. single unit smooth muscle MULTI-UNIT smooth muscle fibers are innervated independently. The fibers are not connected by gap junctions. Depolarization of one fiber is followed by contraction of that fiber only. These fibers are richly innervated by the autonomic nervous system. Nervous stimuli and hormones cause contraction (or relaxation) of these fibers, not stretch. The smooth muscle of the lung airways, in the walls of large arteries, and attached to the hair of the skin are multi-unit fibers. SINGLE UNIT smooth muscle fibers are connected by gap junctions. Depolarization of one fiber triggers synchronous depolarization throughout the bundle followed by contraction of the fiber bundle. That is, many fibers act as one sheet. Single unit fibers are found in the walls of small blood vessels, the GI tract, and uterus where stretching of one fiber creates a coordinated contraction

Answer 352

D. Ca++ dependent myosin phosphorylation In smooth muscle, coupling between the membrane action potentials and contraction is mediated by calcium ions (Ca++). Calcium regulates the thick filament (myosin) to enable cross bridge formation and contraction.

Answer 353

E. A and C A. Phasic contractions are single twitches that can summate to a fused tetanus. C. Tonic contractions are continuous contractions exhibited by single unit smooth muscle

Answer 354

D. B and C B. ligand gated Ca++ channels C. mechano gated Ca++ channels

Answer 355

MYOSIN ATPase has a slow rate of hydrolysis. It hydrolyzes ATP at about 10% of the rate observed in skeletal muscle. Consequently smooth muscle produces **slow, sustained contractions using only 10%** of the ATP that skeletal muscle would require for the same work

Answer 356

TONIC CONTRACTION = sustained contracted state over time without fatigue. PHASIC CONTRACTION = graded force generated by increasing stimulus up to fused tetanus.

Answer 357

MEMBRANE ACTIVATION Contraction of smooth muscle, like skeletal muscle, is dependent on a rise of cytosolic Ca++ due to changes in the plasma membrane. However, smooth muscle **does not have T tubules**. Instead **Ca++ enters from the ECF by diffusion through calcium channels in the plasma membrane**. These Ca++ channels include: **voltage-gated channels, ligand-gated channels and mechano-gated channels**. The inputs that regulate contraction include: Autonomic nervous system via voltage gated Ca++ channels. Hormones via ligand-gated Ca++ channels. Stretch via mechano-gated Ca++ channels. At any one time, multiple inputs, some excitatory and others inhibitory, can be activated in a single cell. The net effect is dependent on the relative intensity of these inputs. Note that the intracellular Ca++ of smooth muscle can increase (or decrease) due to changes in the membrane potential from graded depolarization, hyperpolarization, or an action potential

Answer 358

MEMBRANE ACTIVATION Contraction of smooth muscle, like skeletal muscle, is dependent on a rise of cytosolic Ca++ due to changes in the plasma membrane. However, smooth muscle does not have T tubules. Instead Ca++ enters from the ECF by diffusion through calcium channels in the plasma membrane. These Ca++ channels include: voltage-gated channels, ligand-gated channels and mechano-gated channels. The inputs that regulate contraction include: **Autonomic nervous system via voltage gated Ca++ channels**. Hormones via ligand-gated Ca++ channels. Stretch via mechano-gated Ca++ channels. At any one time, multiple inputs, some excitatory and others inhibitory, can be activated in a single cell. The net effect is dependent on the relative intensity of these inputs. Note that the intracellular Ca++ of smooth muscle can increase (or decrease) due to changes in the membrane potential from graded depolarization, hyperpolarization, or an action potential

Answer 359

MEMBRANE ACTIVATION Contraction of smooth muscle, like skeletal muscle, is dependent on a rise of cytosolic Ca++ due to changes in the plasma membrane. However, smooth muscle does not have T tubules. Instead Ca++ enters from the ECF by diffusion through calcium channels in the plasma membrane. These Ca++ channels include: voltage-gated channels, ligand-gated channels and mechano-gated channels. The inputs that regulate contraction include: Autonomic nervous system via voltage gated Ca++ channels. **Hormones via ligand-gated Ca++ channels.** Stretch via mechano-gated Ca++ channels. At any one time, multiple inputs, some excitatory and others inhibitory, can be activated in a single cell. The net effect is dependent on the relative intensity of these inputs. Note that the intracellular Ca++ of smooth muscle can increase (or decrease) due to changes in the membrane potential from graded depolarization, hyperpolarization, or an action potential

Answer 360

MEMBRANE ACTIVATION Contraction of smooth muscle, like skeletal muscle, is dependent on a rise of cytosolic Ca++ due to changes in the plasma membrane. However, smooth muscle does not have T tubules. Instead Ca++ enters from the ECF by diffusion through calcium channels in the plasma membrane. These Ca++ channels include: voltage-gated channels, ligand-gated channels and mechano-gated channels. The inputs that regulate contraction include: Autonomic nervous system via voltage gated Ca++ channels. Hormones via ligand-gated Ca++ channels. **Stretch via mechano-gated Ca++ channels.** At any one time, multiple inputs, some excitatory and others inhibitory, can be activated in a single cell. The net effect is dependent on the relative intensity of these inputs. Note that the intracellular Ca++ of smooth muscle can increase (or decrease) due to changes in the membrane potential from graded depolarization, hyperpolarization, or an action potential

Answer 361

MEMBRANE ACTIVATION Contraction of smooth muscle, like skeletal muscle, is dependent on a rise of cytosolic Ca++ due to changes in the plasma membrane. However, smooth muscle does not have T tubules. Instead Ca++ enters from the ECF by diffusion through calcium channels in the plasma membrane. These Ca++ channels include: voltage-gated channels, ligand-gated channels and mechano-gated channels. The inputs that regulate contraction include: Autonomic nervous system via voltage gated Ca++ channels. Hormones via ligand-gated Ca++ channels. Stretch via mechano-gated Ca++ channels. **At any one time, multiple inputs, some excitatory and others inhibitory, can be activated in a single cell. The net effect is dependent on the relative intensity of these inputs.** Note that the intracellular Ca++ of smooth muscle can increase (or decrease) due to changes in the membrane potential from graded depolarization, hyperpolarization, or an action potential

Answer 362

[Some smooth muscle exhibits spontaneous contractile activity](http://padlet.com/davidofbuderim/4ova3k99hh1l)in the absence of either nerve or hormonal stimuli. The plasma membranes of these fibers do not maintain a stable resting membrane potential. Instead the resting membrane potential gradually drifts towards threshold where it triggers an action potential (Figure 49). Following repolarization the membrane again begins to depolarize. This is property is called pacemaker activity. Pacemakers are found within the GI tract.

Answer 363

While the battery is **being used in the device it is a galvanic cell** function (using the redox energy to produce electricity). While the battery is **charging it is an electrolytic cell** function (using outside electricity to reverse the completed redox reaction). Galvanic: turns chemical energy into electrical energy Electrolytic Cell: turns electrical energy into chemical energy

Answer 364

All three types of muscle contain the contractile proteins, **myosin and actin,** contract to generate force, and share 3 common principles: Sliding filament mechanism in which myosin filaments bind to and pull actin filaments as a basis for shortening. Regulation of contractile proteins by calcium ions. Changes in membrane potential lead to a rise in intracellular calcium resulting in contraction (E-C coupling)

Answer 365

[padlet](http://padlet.com/davidofbuderim/coz0oorilmez)

Answer 366

[Muscle Tension](http://padlet.com/davidofbuderim/coz0oorilmez) The mechanical response of a single muscle fiber to a single action potential is called a **twitch**. Following an action potential there is brief period before tension, the force exerted on an object, develops. This is known as the latent period. The action potential of a single impulse lasts only 2 milliseconds. The associated contraction time (twitch) lasts for 10-100 milliseconds. This means that repeated stimulation of a skeletal muscle will cause **summation of the contractions until there is no relaxation and fused tetanus is reached** (Figure 45). Not all muscle fibers have the same contraction times. Some fast fibers contract in 10 milliseconds; slower fibers take 100 milliseconds or longer. The duration depends on the SR-ATPase activity.

Answer 367

Length-Tension Relationship. The maximal amount of force (tension) a muscle can generate is determined by the **degree of overlap of the thick and thin filaments** (Figure 46). The basal state and slightly stretched state provide optimal force generation (Figure 46). Because the muscle is anchored to bone within the body, conditions of excess stretch or non-overlap and excess contraction are avoided. However, with injury, irreversible damage to the actin and myosin filaments can occur.

Answer 368

Skeletal Muscle Metabolism Muscle fibers depend on **ATP to produce force**. There are three pathways a muscle fiber uses to make ATP. 1. Creatine phosphate converts ADP to ATP in a single, fast reaction. As a result, 4 moles of ATP are produced per minute from creatine phosphate. However, the stores of creatine phosphate are limited so they are used up in the first 10 seconds of intense exercise. Creatine phosphate is the primary source of ATP during a short, high intensity activity such as the 100 meter dash. 2. Anaerobic metabolism burns glucose as well as the large stores of muscle glycogen (a glucose polymer) to produce lactic acid and ATP in the absence of oxygen. Since only glycolysis is used, 2.5 moles of ATP can be produced per minute. Anaerobic metabolism is used during the first 1.5 minutes of high intensity activity and is the primary source of ATP for the 400 meter dash. 3. Aerobic metabolism uses glycogen, blood glucose, or fatty acids to produce ATP, CO2, and water in the presence of oxygen. Only 1 mole of ATP is made per minute but the available fuel sources are limited only in extreme circumstances. Aerobic metabolism is the primary source of ATP during endurance activities such as a marathon.

Answer 369

Skeletal Muscle Metabolism Muscle fibers depend on ATP to produce force. There are **three pathways** a muscle fiber uses to make ATP. 1. **Creatine phosphate** converts ADP to ATP in a single, fast reaction. As a result, 4 moles of ATP are produced per minute from creatine phosphate. However, the stores of creatine phosphate are limited so they are used up in the first 10 seconds of intense exercise. Creatine phosphate is the primary source of ATP during a short, high intensity activity such as the 100 meter dash. 2. **Anaerobic metabolism** burns glucose as well as the large stores of muscle glycogen (a glucose polymer) to produce lactic acid and ATP in the absence of oxygen. Since only glycolysis is used, 2.5 moles of ATP can be produced per minute. Anaerobic metabolism is used during the first 1.5 minutes of high intensity activity and is the primary source of ATP for the 400 meter dash. 3. **Aerobic metabolism** uses glycogen, blood glucose, or fatty acids to produce ATP, CO2, and water in the presence of oxygen. Only 1 mole of ATP is made per minute but the available fuel sources are limited only in extreme circumstances. Aerobic metabolism is the primary source of ATP during endurance activities such as a marathon.

Answer 370

Skeletal Muscle Metabolism Muscle fibers depend on ATP to produce force. There are three pathways a muscle fiber uses to make ATP. 1. Creatine phosphate converts ADP to ATP in a single, fast reaction. As a result, 4 moles of ATP are produced per minute from creatine phosphate. However, the stores of creatine phosphate are limited so they are used up in the first **10 seconds** of intense exercise. Creatine phosphate is the primary source of ATP during a short, high intensity activity such as the **100 meter dash**. 2. Anaerobic metabolism burns glucose as well as the large stores of muscle glycogen (a glucose polymer) to produce lactic acid and ATP in the absence of oxygen. Since only glycolysis is used, 2.5 moles of ATP can be produced per minute. Anaerobic metabolism is used during the first 1.5 minutes of high intensity activity and is the primary source of ATP for the 400 meter dash. 3. Aerobic metabolism uses glycogen, blood glucose, or fatty acids to produce ATP, CO2, and water in the presence of oxygen. Only 1 mole of ATP is made per minute but the available fuel sources are limited only in extreme circumstances. Aerobic metabolism is the primary source of ATP during endurance activities such as a marathon.

Answer 371

Skeletal Muscle Metabolism Muscle fibers depend on ATP to produce force. There are three pathways a muscle fiber uses to make ATP. 1. Creatine phosphate converts ADP to ATP in a single, fast reaction. As a result, 4 moles of ATP are produced per minute from creatine phosphate. However, the stores of creatine phosphate are limited so they are used up in the first 10 seconds of intense exercise. Creatine phosphate is the primary source of ATP during a short, high intensity activity such as the 100 meter dash. 2. Anaerobic metabolism burns glucose as well as the large stores of muscle glycogen (a glucose polymer) to produce lactic acid and ATP in the absence of oxygen. Since only glycolysis is used, 2.5 moles of ATP can be produced per minute. Anaerobic metabolism is used during the **first 1.5 minutes of high intensity** activity and is the primary source of ATP for the **400 meter dash**. 3. Aerobic metabolism uses glycogen, blood glucose, or fatty acids to produce ATP, CO2, and water in the presence of oxygen. Only 1 mole of ATP is made per minute but the available fuel sources are limited only in extreme circumstances. Aerobic metabolism is the primary source of ATP during endurance activities such as a marathon.

Answer 372

Skeletal Muscle Metabolism Muscle fibers depend on ATP to produce force. There are three pathways a muscle fiber uses to make ATP. 1. Creatine phosphate converts ADP to ATP in a single, fast reaction. As a result, 4 moles of ATP are produced per minute from creatine phosphate. However, the stores of creatine phosphate are limited so they are used up in the first 10 seconds of intense exercise. Creatine phosphate is the primary source of ATP during a short, high intensity activity such as the 100 meter dash. 2. Anaerobic metabolism burns glucose as well as the large stores of muscle glycogen (a glucose polymer) to produce lactic acid and ATP in the absence of oxygen. Since only glycolysis is used, 2.5 moles of ATP can be produced per minute. Anaerobic metabolism is used during the first 1.5 minutes of high intensity activity and is the primary source of ATP for the 400 meter dash. 3. Aerobic metabolism uses glycogen, blood glucose, or fatty acids to produce ATP, CO2, and water in the presence of oxygen. Only 1 mole of ATP is made per minute but the available fuel sources are **limited only in extreme circumstances**. Aerobic metabolism is the primary source of ATP during endurance activities such as a **marathon**.

Answer 373

Skeletal muscle fibers are classified into one of three types distinguished by the speed of their myosin ATPase and preferred metabolism: * *fast, glycolytic fibers** fatigue quickly * *fast, oxidative, glycolytic fibers** resist fatigue * *slow, oxidative fibers** resist fatigue Fast fibers undergo cross-bridge cycling about 4 times faster than slow fibers. Oxidative fibers contain lots of mitochondria for aerobic metabolism during tasks that require endurance. Glycolytic fibers use only small amounts of oxygen and are larger in diameter than oxidative fibers. As a result of their larger diameter, each glycolytic fiber can produce more tension than an oxidative fiber. Most skeletal muscles include all three fiber types. However, each motor unit contains only a single type of muscle fiber. Motor units containing slow, oxidative fibers contain fewer fibers than motor units containing fast fibers. Recruitment is the process of activating different types of muscle fibers within a fascicle in response to need. Recruitment starts with slow, oxidative fibers that do not provide a lot of force but can provide fine muscle control. If more tension is needed, fast-oxidative-glycolytic fibers can be recruited. Finally, fast, glycolytic fibers that fatigue rapidly increase tension the most dramatically are recruited.

Answer 374

Skeletal muscle fibers are classified into one of three types distinguished by the speed of their myosin ATPase and preferred metabolism: * *fast, glycolytic fibers** fatigue quickly * *fast, oxidative, glycolytic fibers** resist fatigue * *slow, oxidative fibers** resist fatigue Recruitment is the process of activating different types of muscle fibers within a fascicle in response to need. Recruitment **starts with slow, oxidative fibers** that do not provide a lot of force but can provide fine muscle control. **If more tension is needed, fast-oxidative-glycolytic fibers can be recruited**. **Finally, fast, glycolytic fibers** that fatigue rapidly increase tension the most dramatically are recruited.

Answer 375

relaxation

Answer 376

λ = c / f

Answer 377

Light (of appropriate intensity and frequency) incident upon a metal ejects a photoelectron [padlet](http://padlet.com/davidofbuderim/oqqr8a6oa1vs)

Answer 378

E-C coupling ([excitation-contraction coupling](http://padlet.com/davidofbuderim/coz0oorilmez)) (Figure 44) refers to the electrical events which trigger a contraction. Each skeletal muscle is innervated by an alpha motor neuron. An action potential arriving at the neuromuscular junction releases the neurotransmitter acetylcholine from the

Answer 379

In skeletal muscle, Ca++ is stored within the cell in a **membrane bound compartment** called the **sarcoplasmic reticulum** (SR). The SR wraps around myofibrils. Ca++ is released from the SR into the cytoplasm in response to an electrical signal (action potential). The action potential opens a voltage gated channel in the T tubule (invagination of the plasma membrane) which is adjacent to the SR (Figure 44). This voltage gated channel is called the dihydropyridine receptor. Activation of the dihydropyridine receptor in turn opens a Ca++ channel (ryanodine receptor) on the SR and Ca++ enters the cytoplasm (Figure 44). Ca++ is taken back up into the SR from the cytoplasm by the SR CaATPase.

Answer 380

Equilibrium potentials Due to the concentration gradient of ions across the plasma membrane of cells, the intracellular fluid has a small excess of negative charge compared to the extracellular fluid. The separation of charge has the potential to do work. As a result, the magnitude of the charge difference between the inside and outside of the cell is referred to as the **membrane potential and measured in millivolts**. If there is an excess of negative charges on the inside of the cell, the membrane potential is negative. If the excess charge on the inside of the cell is positive, the membrane potential is positive. The **membrane potential** of a cell under specific conditions is determined by the **concentration of ions inside and outside of the cell** and by the **permeability of the membrane for those ions**

Answer 381

1. Bicarbonate ion 2. Carbonic acid which dissociates into bicarbonate and proton

Answer 382

B. 1.4 Liters

Answer 383

C. increased thickness of the alveolar capillary membrane

Answer 384

A. 8.28 Liters/min

Answer 385

B. The compliance of the lung is decreased

Answer 386

B. functional residual capacity is greater than normal due to increased lung compliance.

Answer 387

D. lung to collapse inward and the chest wall to spring outward

Answer 388

C. alveolar pressure will be equal to atmospheric pressure.

Answer 389

C. the sum of residual volume and vital capacity.

Answer 390

B. The amount of O2 carried by Hb in the blood will not rise appreciably

Answer 391

A. increased due to the rise in temperature and fall in pH

Answer 392

B. increase

Answer 393

A, B and C

Answer 394

High lung volume

Answer 395

end of inspiration

Answer 396

A arterioles that perfuse the lung alveoli

Answer 397

B left shifted indicating higher affinity for O2

Answer 398

A increased

Answer 399

B PaCO2 and PaO2 to show little or no change from resting values.

Answer 400

B PaCO2 to decrease

Answer 401

[padlet](http://padlet.com/davidofbuderim/m81s0oga0rtp)

Answer 402

[Sulfide](https://docs.google.com/spreadsheets/d/1BJ2kdjusZqnTeGS627uXN_9zgGdSW2Edye9oP8oEgi0/edit#gid=1870605008) R-S-R [Thiol R-SH](https://docs.google.com/spreadsheets/d/1BJ2kdjusZqnTeGS627uXN_9zgGdSW2Edye9oP8oEgi0/edit#gid=844983111)

Answer 403

[Alkyl Halide](https://docs.google.com/spreadsheets/d/1BJ2kdjusZqnTeGS627uXN_9zgGdSW2Edye9oP8oEgi0/edit#gid=1351463628) R-X [Acyl halide](https://docs.google.com/spreadsheets/d/1BJ2kdjusZqnTeGS627uXN_9zgGdSW2Edye9oP8oEgi0/edit#gid=876923948) sim ketone

Answer 404

Amine Nitro Nitrile Imine Amide Enamine [google doc for functional groups](https://docs.google.com/spreadsheets/d/1BJ2kdjusZqnTeGS627uXN_9zgGdSW2Edye9oP8oEgi0/edit#gid=1298515092)

Answer 405

[padlet](http://padlet.com/davidofbuderim/m81s0oga0rtp) 1. The side with more moles of gas

Answer 406

[padlet](http://padlet.com/davidofbuderim/m81s0oga0rtp) 1. Reactants

Answer 407

[padlet](http://padlet.com/davidofbuderim/m81s0oga0rtp) 1. None - doesn't change the partial pressures of the reactants and products so is not a disturbance

Answer 408

1. A C=C bond is a **reaction hot spot** in a molecule. It should be the site of a lot of **chemical action**

Answer 409

What does the term "nucleophilic substitution" imply ? A nucleophile is an **electron** rich species that will react with an **electron** poor species A substitution implies that one group **replaces** another. Nucleophilic substitution reactions occur when an electron rich species, the nucleophile, reacts at an electrophilic saturated C atom attached to an electronegative group (important), the leaving group The electrophilic C can be recognised by looking for the polar σ bond due to the presence of an electronegative substituent (esp. C-Cl, C-Br, C-I and C-O) Nucleophilic substitution reactions are an important class of reactions that allow the interconversion of functional groups. Of particular importance are the reactions of alkyl halides (R-X) and alcohols (R-OH) For alcohols, the range of substitution reactions possible can be increased by utilising the tosylates (R-OTs), an alternative method of converting the -OH to a better leaving group.

Answer 410

_{What does the term "nucleophilic substitution" imply ?} _{A nucleophile is an electron rich species that will react with an electron poor species
A substitution implies that one group replaces another.} Nucleophilic substitution reactions occur when an **electron rich species, the nucleophile**, reacts at an **electrophilic saturated C atom** attached to an **electronegative** group (important), the **leaving** group _{The electrophilic C can be recognised by looking for the polar σ bond due to the presence of an electronegative substituent (esp. C-Cl, C-Br, C-I and C-O)} _{Nucleophilic substitution reactions are an important class of reactions that allow the interconversion of functional groups.} _{Of particular importance are the reactions of alkyl halides (R-X) and alcohols (R-OH)} _{For alcohols, the range of substitution reactions possible can be increased by utilising the tosylates (R-OTs), an alternative method of converting the -OH to a better leaving group.}

Answer 411

_{What does the term "nucleophilic substitution" imply ?} _{A nucleophile is an electron rich species that will react with an electron poor species
A substitution implies that one group replaces another.} _{Nucleophilic substitution reactions occur when an electron rich species, the nucleophile, reacts at an electrophilic saturated C atom attached to an electronegative group (important), the leaving group} The electrophilic C can be recognised by looking for the **polar σ bond** due to the presence of an **electronegative** substituent (esp. C-Cl, C-Br, C-I and C-O) _{Nucleophilic substitution reactions are an important class of reactions that allow the interconversion of functional groups.} _{Of particular importance are the reactions of alkyl halides (R-X) and alcohols (R-OH)} _{For alcohols, the range of substitution reactions possible can be increased by utilising the tosylates (R-OTs), an alternative method of converting the -OH to a better leaving group.}

Answer 412

What does the term "nucleophilic substitution" imply ? Nucleophilic substitution reactions are an important class of reactions that allow the **interconversion** of **functional groups**. _{Of particular importance are the reactions of alkyl halides (R-X) and alcohols (R-OH)} _{For alcohols, the range of substitution reactions possible can be increased by utilising the tosylates (R-OTs), an alternative method of converting the -OH to a better leaving group.}

Answer 413

What does the term "nucleophilic substitution" imply ? Of particular importance are the reactions of **alkyl halides (R-X)** and alcohols **(R-OH)** _{For alcohols, the range of substitution reactions possible can be increased by utilising the tosylates (R-OTs), an alternative method of converting the -OH to a better leaving group.}

Answer 414

Some smooth muscle exhibits [spontaneous contractile activity](http://padlet.com/davidofbuderim/4ova3k99hh1l)in the absence of either nerve or hormonal stimuli. The plasma membranes of these fibers do not maintain a stable resting membrane potential. Instead the resting membrane potential gradually drifts towards threshold where it triggers an action potential (Figure 49). Following repolarization the membrane again begins to depolarize. This is property is called pacemaker activity. ## Footnote **Pacemakers are found within the GI tract.**

Answer 415

SINGLE VERSUS MULTI-UNIT FIBERS Smooth muscle fibers do not have a specific neuro-muscular junction. Instead as the autonomic nerve nears a bundle of smooth muscle, it divides into many branches each containing a series of swellings (called varicosities) filled with vesicles of neurotransmitters. **MULTI-UNIT smooth muscle** fibers are innervated independently. The fibers are not connected by gap junctions. Depolarization of one fiber is followed by contraction of that fiber only. These fibers are richly innervated by the autonomic nervous system. Nervous stimuli and hormones cause contraction (or relaxation) of these fibers, not stretch. The smooth muscle of the lung airways, in the walls of large arteries, and attached to the hair of the skin are multi-unit fibers. **SINGLE UNIT smooth muscle** fibers are connected by gap junctions. Depolarization of one fiber triggers synchronous depolarization throughout the bundle followed by contraction of the fiber bundle. That is, many fibers act as one sheet. Single unit fibers are found in the walls of small blood vessels, the GI tract, and uterus where stretching of one fiber creates a coordinated contraction

Answer 416

In smooth muscle, coupling between the membrane action potentials and contraction is mediated by calcium ions (Ca++). Calcium regulates the **thick filament (myosin)** to enable cross bridge formation and contraction.

Answer 417

[cardiac muscle cell](http://padlet.com/davidofbuderim/djz4ork23k1n)

Answer 418

CONDUCTING cardiac muscle cells **are ~ 1% of the cardiac** muscle cells. These are large diameter cells that do not produce tension, instead they are specialized for excitation. They constitute a network in the heart known as a conduction system. They are connected to the contractile cells by gap junctions. The conducting fibers are filled mostly with glycogen and have few myofilaments. These cells are the intrinsic pacemakers. We will deal with their action potentials in the next lecture.

Answer 419

CONTRACTILE cardiac muscle cells are **slow oxidative muscle fibers**. These fibers form the walls of the heart, shorten and produce tension. They use glucose and fatty acids as substrates.

Answer 420

The Henderson-Hasselbalch approximation allows us one method to approximate the pH of a buffer solution pH = pKa + log ([A−] / [HA]) HA is the acid, A- is the conjugate base [padlet](http://padlet.com/davidofbuderim/i21vv5axnfrq) [derivation](http://www.chemteam.info/AcidBase/HH-Equation.html)

Answer 421

The Henderson-Hasselbalch approximation allows us one method to approximate the pH of a buffer solution pH = pKa + log ([A−] / [HA]) HA is the acid, A- is the conjugate base [padlet](http://padlet.com/davidofbuderim/i21vv5axnfrq) [derivation](http://www.chemteam.info/AcidBase/HH-Equation.html)

Answer 422

ELECTRICAL – CONTRACTION (E-C) COUPLING As in skeletal muscle, contraction in cardiac muscle is dependent on the entry of _Ca++ from the **T tubule** (Figure 51)._ Depolarization of the T tubule membrane opens the voltage gated Ca++ channels (dihydropyridine receptor), permitting the entry of a small amount of Ca++. This Ca++ opens the Ca++ gated Ca++ channel (ryanodine receptor) on the sarcoplasmic reticulum (SR) thereby releasing a lot of Ca++ into the cytoplasm. In turn, Ca++ binds to troponin which unmasks the actin (thin filament), cross bridges form, and shortening occurs. With repolarization of the T tubule membrane, no further Ca++ enters the cells and the SR CaATPase removes Ca++ from the cytoplasm. This removal of Ca++ ends the contractile cycle and the muscle relaxes

Answer 423

[ELECTRICAL – CONTRACTION (E-C) COUPLING](http://padlet.com/davidofbuderim/djz4ork23k1n) As in skeletal muscle, contraction in cardiac muscle is dependent on the entry of Ca++ from the T tubule (Figure 51). 1. Depolarization of the T tubule membrane opens the voltage gated Ca++ channels (dihydropyridine receptor), permitting the entry of a small amount of Ca++. 2. This Ca++ opens the Ca++ gated Ca++ channel (ryanodine receptor) on the sarcoplasmic reticulum (SR) thereby releasing a lot of Ca++ into the cytoplasm. 3. In turn, Ca++ binds to troponin which unmasks the actin (thin filament), cross bridges form, and shortening occurs. With repolarization of the T tubule membrane, no further Ca++ enters the cells and the SR CaATPase removes Ca++ from the cytoplasm. This removal of Ca++ ends the contractile cycle and the muscle relaxes

Answer 424

[ACTION POTENTIAL OF CONTRACTILE CARDIAC CELLS](http://padlet.com/davidofbuderim/djz4ork23k1n) The action potential of the contractile cardiac muscle fiber (Figure 52) is longer in duration (200-220 msec) than that seen in skeletal muscle (2 msec). In cardiac cells there are four phases to the action potential. Phase 0, voltage gated Na+ channels open. Phase 1, voltage gated Na+ channels inactivate and voltage gated K+ channels open. Phase 2 (plateau), voltage gated Ca++ channels open and voltage gated K+ channels remain open. Phase 3, only voltage gated K+ channels are open and cells repolarize. Phase 4, all of the voltage gated channels are closed and the resting membrane potential is restored by the Na/K ATPase. Note that the entry of Ca++ in phase 2 is essential for initiating contraction and triggering the opening of the Ca++ gated Ca++ release channel (ryanodine receptor). One other point, each action potential results in one contraction. One contraction (twitch) is ~250 msec, almost the same duration as the action potential (200 msec). This is due to the prolonged plateau phase 2.

Answer 425

[REFRACTORY PERIOD AND ABSENCE OF TETANUS](http://padlet.com/davidofbuderim/djz4ork23k1n) Absolute refractory period of the cardiac muscle action potential refers to the time interval when the voltage gated sodium channels are inactivated. **The absolute refractory period lasts ~180 msec.** **The action potential lasts 200-220 msec.** **A single contraction is 250 msec.** _{Recall that these voltage gated Na+ channels must undergo a conformational change from an “inactivated” state to a “closed” state before they can reopen and initiate another action potential. As a consequence of phase 2, the voltage gated Na+ channels remain “inactivated” for an extended period of time and do not “close” until repolarization in phase 3 (~180 msec). No amount of stimulus can cause an action potential during the absolute refractory period.} An important point regarding the refractory period is that contractions cannot sum and therefore **there is no fused tetanus (summed contractions).** Fused tetanus in the heart would lead to death as it would prevent the rhythmic pumping of blood.

Answer 426

the twitch would be shorter the SR Ca+2-ATPase pumps Ca++ back into the Sarcoplasmic Reticulum

Answer 427

C fused tetanus would be reached later than an untreated fiber the SR Ca+2-ATPase pumps Ca++ back into the Sarcoplasmic Reticulum

Answer 428

B slow-oxidative, fast-oxidative, fast-glycolytic Skeletal muscle fibers are classified into one of three types distinguished by the speed of their myosin ATPase and preferred metabolism: fast, glycolytic fibers fatigue quickly fast, oxidative, glycolytic fibers resist fatigue slow, oxidative fibers resist fatigue Recruitment is the process of activating different types of muscle fibers within a fascicle in response to need. Recruitment starts with slow, oxidative fibers that do not provide a lot of force but can provide fine muscle control. If more tension is needed, fast-oxidative-glycolytic fibers can be recruited. Finally, fast, glycolytic fibers that fatigue rapidly increase tension the most dramatically are recruited.

Answer 429

A both cardiac muscle and single-unit smooth muscle

Answer 430

troponin–tropomyosin complexes

Answer 431

[always reach threshold](http://padlet.com/davidofbuderim/4ova3k99hh1l)

Answer 432

L = m v r (v is tangential to r) L = ρ r (ρ is tangential to r) L = m ω r²

Answer 433

[four graphs showing results of the photoelectric effect](http://padlet.com/davidofbuderim/oqqr8a6oa1vs)

Answer 434

[Rydberg equation](http://padlet.com/davidofbuderim/oqqr8a6oa1vs) 2. Photoelectric effect / emission spectra

Answer 435

Answer 1: B. Bradycardia Answer 2: C. His Bundle-Purkinje

Answer 436

1. B pressure differences between the heart chambers

Answer 437

B. His stroke volume decreases to 33 ml

Answer 438

Answer 1: B. increased systemic pressure (after load)

Answer 439

Answer 2: B. aortic valve opens

Answer 440

Answer 3: D. aortic valve closes

Answer 441

Answer 4: A. Yes, each is 60 mls

Answer 442

Answer 5: B. No. Black loop EJ = 60/120 x 100 = 50%; Red loop EJ = 60/150 x 100 = 40%

Answer 443

Answer 1: C. local vasodilation due to the build up of metabolites.

Answer 444

Answer 2: A. Resistance increases

Answer 445

Answer 3: A. MAP increases

Answer 446

Answer 4: A. Afterload is increased Afterload is the pressure against which the heart must work to eject blood during systole (systolic pressure). The lower the afterload, the more blood the heart will eject with each contraction. Like contractility, changes in afterload will raise or lower the Starling curve relating stroke volume index to LAP. The effect of afterload on stroke colume is due to the fact that the maximum pressure that the heart can develop is smaller at lower ventricular volumes. Therefore, if the systolic pressure is lower, the heart will be able to contract to a smaller volume at the end of systole. This will result in an improved stroke volume. Conversely, if the systolic pressure is higher, the heart will be unable to contract to as small a vollume at the end of systole and the stroke volume index will be decreased.

Answer 447

Answer 1: B. Decreased firing of the carotid baroreceptors

Answer 448

Answer 2: C. increased metabolites in the IS surrounding the muscle

Answer 449

Answer 3: B. Lower capillary hydrostatic pressure

Answer 450

Answer 4: A. Increases

Answer 451

A. thin walled vessels which permit exchange of materials between blood and interstitial fluid. Well done!

Answer 452

D. A and B Well done!

Answer 453

C. pressure Well done!

Answer 454

E. A, B, C, and D Well done!

Answer 455

B. decreased vessel diameter Well done!

Answer 456

D. A and B Well done!

Answer 457

B. K+ Well done!

Answer 458

D. Ca++ influx and K+ efflux Well done!

Answer 459

C. stroke volume Well done!

Answer 460

B. Increased parasympathetic stimulation Well done!

Answer 461

B. increased parasympathetic stimulation of nodal fibers Well done!

Answer 462

B. QRS complex Well done!

Answer 463

C. T Wave Well done!

Answer 464

A. P wave Well done!

Answer 465

E. unchanged Well done!

Answer 466

D. B and C Well done!

Answer 467

C. arterioles Well done!

Answer 468

C. reflex vasoconstriction of the peripheral blood vessels occurs Well done!

Answer 469

D. A and B Well done!

Answer 470

C. increases the force of contraction Well done!

Answer 471

[padlet-electrical conduction in the heart](http://padlet.com/davidofbuderim/gpf807lxm9f9)

Answer 472

[Pacemaker cells](http://padlet.com/davidofbuderim/gpf807lxm9f9) have the unique property of being able to generate action potentials spontaneously (i.e. without input from the nervous system). They can generate an action potential because their resting membrane potential (- 60mV) is unstable. This potential exists because the pacemaker cells have unusual channels that are permeable to both Na + and K+. These channels are called If channels. _{The "f" is derived from the fact that they were originally called "funny" channels because the If channels are Na+ channels with unusual properties}. When the If channels opens, the influx of Na+ exceeds the efflux of K + and the net influx of positive charges slowly depolarizes the cell. As the membrane potential becomes more positive, the If channels close and the Ca++ channels open transiently, which further depolarize the cell. When the threshold potential is reached, a burst of Ca++ channels open, more Ca++ rushes in, and a steep phase of depolarization (Phase2) occurs (Figure 56). At the peak of the action potential, K+ channels open, K+ rushes out of the cell and the cell repolarizes

Answer 473

[Pacemaker cells](http://padlet.com/davidofbuderim/gpf807lxm9f9) have the unique property of being able to generate action potentials spontaneously (i.e. without input from the nervous system). They can generate an action potential because their resting membrane potential (- 60mV) is unstable. This potential exists because the pacemaker cells have **unusual channels that are permeable to both Na + and K+**. These channels are **called If channels**. _{The "f" is derived from the fact that they were originally called "funny" channels because the If channels are Na+ channels with unusual properties}. When the If channels opens, the influx of Na+ exceeds the efflux of K + and the net influx of positive charges slowly depolarizes the cell. As the membrane potential becomes more positive, the If channels close and the Ca++ channels open transiently, which further depolarize the cell. When the threshold potential is reached, a burst of Ca++ channels open, more Ca++ rushes in, and a steep phase of depolarization (Phase2) occurs (Figure 56). At the peak of the action potential, K+ channels open, K+ rushes out of the cell and the cell repolarizes

Answer 474

The pacemaker cells set the rate of the heartbeat. They are anatomically distinct from the contractile cells because they have no organized sarcomeres and therefore do not contribute to the contractile force of the heart. There are several different pacemakers in the heart but the **sinoatrial node (SA)** is the fastest. **In normal hearts, the SA node is the pacemaker**. The other conduction tissue (AV), Bundle of His and Purkinje Fibers will take over in disease states according to their speed of depolarization (AV \> bundle of His \>Purkinje).

Answer 475

HEART RATE (HR) can be modulated by **autonomic nervous stimulation**. Increased **parasympathetic** stimulation of muscarinic receptors on the heart **slows the firing of the SA node**. Parasympathetic stimulation does so by delaying the closing of K+ channels (efflux). The increased K+ efflux further hyperpolarizes the cells and slows the opening of the If channels. In contrast, **sympathetic stimulation speeds heart rate by shortening the time to threshold.** Sympathetic stimulation increases Na influx via the If channels and closes the K channels

Answer 476

MYOCARDIAL CONTRACTILE CELLS are tightly linked to one another by **intercalated discs, specialized adhesive junctions, which ensure transmission of force** from one myocardial cell to an adjacent cell. The cells also contain **gap junctions that facilitate transmission of electrical impulses** from cell to cell. Myocardial contractile cells have a resting membrane potential of approximately -85 millivolts (mV). Depolarization occurs when the permeability to sodium increases, and sodium flows into the cell (Phase 0, Figure 57). As the membrane potential reaches about +20 mV, the voltage gated sodium channels inactivate. The muscle cell begins to repolarize as K+ leaves the cell through open voltage gated K+ channels (Phase 1). At this membrane potential, voltage gated Ca++ channels open causing the action potential to flatten as the K+ efflux balances the Ca++ influx. The plateau (Phase 2) ends when Ca ++ channels close and K+ efflux exceeds Ca++ influx. In Phase 3, K+ efflux repolarizes the muscle cell. The resting membrane potential is maintained by the activity of the Na-K ATPase (Phase 4)

Answer 477

Myocardial contractile cells have a resting membrane potential of approximately -85 millivolts (mV). Depolarization occurs when the permeability to sodium increases, and sodium flows into the cell (Phase 0, Figure 57). As the membrane potential reaches about +20 mV, the voltage gated sodium channels inactivate. The muscle cell begins to repolarize as K+ leaves the cell through open voltage gated K+ channels (Phase 1). At this membrane potential, voltage gated Ca++ channels open causing the action potential to flatten as the K+ efflux balances the Ca++ influx. The plateau (Phase 2) ends when Ca ++ channels close and K+ efflux exceeds Ca++ influx. In Phase 3, K+ efflux repolarizes the muscle cell. The resting membrane potential is maintained by the activity of the Na-K ATPase (Phase 4)

Answer 478

An ECG recording is the **sum of all of the electrical potentials** generated by all the cells of the heart at any instance in time. Each deflection (wave) of the ECG **represents either depolarization or repolarization** of the specific parts of the heart. Because depolarization occurs before mechanical contraction, the waves of depolarization can be associated with contraction and relaxation of the atria and the ventricles. A typical ECG recording and the waves are shown below (Figure 58). The P wave corresponds to depolarization of the atria. The QRS complex corresponds to depolarization of the ventricles. The T wave corresponds to repolarization of the ventricle.

Answer 479

_{An ECG recording is the sum of all of the electrical potentials generated by all the cells of the heart at any instance in time.} _{Each deflection (wave) of the ECG represents either depolarization or repolarization of the specific parts of the heart.} _{Because depolarization occurs before mechanical contraction, the waves of depolarization can be associated with contraction and relaxation of the atria and the ventricles.} [A typical ECG recording](http://padlet.com/davidofbuderim/gpf807lxm9f9) and the waves are shown below (Figure 58). The P wave corresponds to depolarization of the atria. The QRS complex corresponds to depolarization of the ventricles. The T wave corresponds to repolarization of the ventricle.

Answer 480

1. Normally each heart beat starts in the pacemaker cells of the **sinoatrial (SA) node** located **in the right atria**. 2. From the SA node, the wave of depolarization moves through **both atria (P wave), resulting in atrial contraction.** 3. The impulse then passes **through the intranodal pathways** connecting the SA node with the **atrioventricular node (AV node)**. At the AV node the **impulse slows** allowing the **atria to contract before the ventricles depolarize**. 4. The impulse then passes from the AV node through specialized conducing tissue known as the Bundle of His. The Bundle of His branches (left and right) within the septum that separates the ventricles and then into the Purkinje fiber system, which carry the impulse through the ventricular walls (QRS complex). This specialized conduction system ensures that the ventricles contract in a synchronized fashion and results in a contraction that begins at the apex (tip) of the heart. This is important because blood is ejected through the valves (pulmonic and aorta) that are located at the base of the heart (at the A-V junction).

Answer 481

Carbohydrates can be represented by the stoichiometric formula **(CH₂O)n,** where n is the number of carbons in the molecule. Therefore, the ratio of carbon to hydrogen to oxygen is 1:2:1 in carbohydrate molecules. The origin of the term “carbohydrate” is based on its components: carbon (“carbo”) and water (“hydrate”). Carbohydrates are classified into three subtypes: monosaccharides, disaccharides, and polysaccharides.

Answer 482

The **right side of the heart has a thin muscular wall and works at low pressures**. Contraction of the right ventricle (RV) pumps blood into the pulmonary circulation (lungs) where oxygen is taken up and carbon dioxide is eliminated. The **left side of the heart has a thicker muscular wall and works at higher pressures.** Contraction of the left ventricle (LV) pumps blood into the systemic circulation for delivery to the limbs and to all of the organs. The right atrium (RA) receives blood returning from the systemic circulation; the left atrium (LA) receives blood from the lungs (Figure 59). Total amount of blood circulating is ~5 liters/ minute

Answer 483

The right side of the heart has a thin muscular wall and works at low pressures. Contraction of the right ventricle (RV) pumps blood into the pulmonary circulation (lungs) where oxygen is taken up and carbon dioxide is eliminated. The left side of the heart has a thicker muscular wall and works at higher pressures. Contraction of the left ventricle (LV) pumps blood into the systemic circulation for delivery to the limbs and to all of the organs. The right atrium (RA) receives blood returning from the systemic circulation; the left atrium (LA) receives blood from the lungs (Figure 59). **Total amount of blood circulating is ~5 liters/ minute**

Answer 484

1. Note that blood enters and leaves the ventricles at the base (A-V junction). 2. That means that the ventricles must contract from the bottom (apex) upward to expel the blood from the base

Answer 485

[Four valves are embedded within the cardiac skeleton between the atria and ventricles.](http://padlet.com/davidofbuderim/gpf807lxm9f9) These valves respond passively to pressure gradients. The pulmonic and aortic valves open when the ventricles contract and close with relaxation. The pulmonic and aortic valves prevent back flow from the arteries into the relaxing ventricles. The AV valves (mitral and tricuspid) close once the ventricles fill. These two valves are closed during contraction of the ventricles and ejection of blood and therefore experience high pressures. To prevent the mitral and tricuspid valves from prolapse (being pushed into the atria) they are tethered to the ventricle wall via tendon like cords and the papillary muscles. The pulmonic and aortic valves do not have tendons to resist prolapse, instead they are semilunar valves (cup like in shape) which fill with blood when closed. These two valves are closed during relaxation and passive filling of the ventricles

Answer 486

[Pressure-volume loop ABCD depicts changes in left ventricle in one beat.](http://padlet.com/davidofbuderim/gpf807lxm9f9) The ventricle fills between A-B. Interval B-C depicts isovolumic contraction. Interval C-D depicts ejection. Interval D-A depicts isovolumic relaxation

Answer 487

CARDIAC OUTPUT (CO) is the **volume of blood ejected by one ventricle in a period of time.** Cardiac output is one measure of the effectiveness of the heart as a pump. It dynamically adjusts by **changing either the heart rate or stroke volume or both**. **Cardiac output = stroke volume x heart rate** **CO= SV x HR** For an average resting heart rate of 70 beats per min (bpm) and a stroke volume of 70 mL per beat, the CO = ~ 5L/min. The average total volume of blood circulating in the body is ~ 5L. Therefore, each ventricle pumps all of the blood of the body through it in only one minute.

Answer 488

EJECTION FRACTION (EF) describes the efficiency of the heart. It is Stroke volume(SV) divided by end diastolic volume (EDV) times 100. **EF (%) = SV/ EDV x 100** During strenuous exercise, CO can increase to 30-35 L/min. What parameter (stroke volume or heart rate) limits this increase in CO? [Answer: heart rate.] As heart rate increases, the time for contraction and relaxation of the cardiac muscle shorten; the filling time limits CO.

Answer 489

**PRELOAD is the degree of stretch of the myocardium before contraction**. An **increase in venous return (filling) will increase preload** and thus increase the force of contraction. [Consider the P-V loop depicted in Figure 63.](http://padlet.com/davidofbuderim/gpf807lxm9f9) An increase in preload (filling) will move the EDV to the right along the X axis and increase the pressure generated (Y axis). The heart (depicted as ABCD) when filled to an EDV of 140 ml, generates a systolic pressure of 180 mmHg. The “red curved” line in Figure 63 depicts the force generated for each increase in EDV for this particular heart.

Answer 490

Four factors can increase venous return (EDV): 1. Skeletal muscle pump in which contraction of leg muscles surrounding the veins aids in returning blood to the heart. 2. Respiratory pump in which deep breathing expands the chest and decreases the intra-thoracic cavity pressure. 3. Sympathetic nervous system activation leads to greater constriction of the arterial vessels and large veins which moves the blood to the heart. 4. Increase in blood volume as in blood doping.

Answer 491

C. is represented by the T wave on the electrocardiogram (ECG).

Answer 492

changes in pressure in adjacent chambers

Answer 493

Sinoatrial (SA) node

Answer 494

PR interval

Answer 495

filtration; absorption

Answer 496

increasing the stroke volume

Answer 497

(ii) \> (i)

Answer 498

decreased firing

Answer 499

Available electrons = (valence electrons) Needed electrons = (to fill shells) Shared electrons = (needed - available) Bonds = (1/2 shared electrons) Draw the bonds and fill in lone pairs as required

Answer 500

single bond = 1 electron domain Lone pair = 1 electron domain Double bond = 1 electron domain Triple bond = 1 electron domain 2. Electrons in a single domain cannot be separated spatially =\> bond angles

Answer 501

[table](http://www.ptable.com/)

Answer 502

[table](http://www.ptable.com/)

Answer 503

[table](http://www.ptable.com/)