All 02 cards Flashcards
(554 cards)
1
Q
What are the two properties that influence whether a particle can permeate the membrane?
A
1) Solubility of that particles to lipids. 2) Size of the molecule.
2
Q
What is the typical movement of Ca+ and Na+ at resting membrane potential?
A
They flow inward, causing depolarization.
3
Q
What is osmolarity?
A
The concentration of osmotically active particles present in a solution.
4
Q
Why do large and complex animals require a functional cardiovascular system?
A
Because they have to maintain their high metabolism
5
Q
Describe temporal summation:
A
Neurotransmitter are release close together in time.
6
Q
What are waxes?
A
Highly nonpolar and impermable compound that are plastic at room temperature.
7
Q
What is the difference in terms of action between paracrine and endocrine action?
A
Paracrines are local messengers, cover short distances and are distributed by simple diffusion whereas endocrine action is long distance and rely on the transport of the blood
8
Q
Describe neurohormones:
A
Hormones released into the blood by neurosecretory neurons.
9
Q
Describe monosaccharides
A
They are single and simple sugar used to assemble larger polymers.
10
Q
What are the two properties that influence whether a particle can permeate the membrane?
A
1) Solubility of that particles to lipids. 2) Size of the molecule.
11
Q
What is osmosis?
A
The net diffusion of water down its concentration gradient through a selectively permeable molecule.
12
Q
Describe the mitchondrion
A
Is where the energy stored in the bonds of carbohydrates and fatty acid is converted into a useful form for the cell.
13
Q
What are the features found in SOME prokaryotic cells?
A
1) Cell wall 2) Internal membrane 3) Flagella 4) Fimbriae and pili 5) Cytoskeleton
14
Q
Describe chemical equilibrium:
A
Chemical equilibrium is reached when the rate of the forward reaction is equal to the rate of the reverse reaction.
15
Q
Describe active driving forces:
A
Require cell to expend energy in the form of ATP to transport substances across the membrane.
16
Q
What is the general formula of carbohydrates?
A
Cx(H2O)y. The carbon atoms are bonded with both hydrogen atoms and hydroxyl groups.
17
Q
State the functions of the lipid bilayer:
A
1- It forms the basic sctructure of the plasma membrane 2- Its hydrophobic interior serves as a barrier between the inside and the outside of the cell. 3-It’s responsable for the fluidity of the membrane.
18
Q
Describe the active site in the cleft:
A
The active site is the region that exhibit the highest degree of complementarity with the shape of the substrate and participate to the strongest interaction with it.
19
Q
Describe secondary active transport:
A
Energy is required but not used directly to produce movement against concentration gradient. The transfer of a solute across the membrane is coupled with the transfer of the ion that supplies the driving force.
20
Q
Describe isolated system:
A
Isolated system cannot exchange either energy or matter with the sorroundings.
21
Q
If ΔG=0
A
The reaction is at thermal equilibrium
22
Q
What happens a few days before mestruation?
A
The anterior pituitary begins to increase secretion of FSH and LH.
23
Q
What’s a substrate?
A
Substrate is a molecule whose reaction is catalysed by an enzyme.
24
Q
Describe the structure of hemoglobin:
A
Is a protein consisting of 4 polypeptide groups sorrounded by a heme group that can reversibly bind to a O2 molecule.
25
What are the properties of the plasma membrane?
1- Forms the outer boundary of the cell 2- It's selectively permeable 3- Controls the entrance of nutrients and exit of waste products. 4- Mantain the difference in concentration between the inside and the outside of the cell. 5- Particippiate in the joining of cells to form tissues and organs. 6- Allow cells to interact in different ways with the same extracellular fluid.
26
What are the two hormones responsable for the correct function of molting in arthropods?
-PTTH -Juvenile hormone
27
Describe the backbone of DNA and RNA:
Is a chain of sugars and phosphate groups linked by phosphodiester linkages.
28
Describe antiport:
Solute and Na+ move in opposite directions.
29
Describe primary active transport:
Energy is directly required to move a substance against its concentrationg gradient.
30
What is the primary target of ADH?
The kidney
31
Where are the receptos for lipophilic hormones located?
They can pass through the plasma membrane and bind to specific receptors inside the cell.
32
What's energy change?
Energy change is the difference between the energy consumed by the breaking of bonds and the energy release by the formation of bonds.
33
Describe the characteristics of a closed circulatory system:
It contains the circulatory fluid in a continous system of vessels so that blood cels and large molecules remains in the system while water and small molecules leak out the capillaries.
34
Describe facilitated diffusion:
It doesn't require energy and use a carrier to facilitate the transfer of a substance down its concentration gradient.
35
What are the reasons why oxygen can be obtained more easily from air than from water?
1) O2 content of air is much higher than O2 in water. 2) Diffuses 8000 more rapidly in water than in the air. 3) More energy is required to move water than air because water is more dense.
36
Describe amino sugars:
An hydroxyl group is replace with an amino group.
37
What are the three different forms of cell adhesion?
-CAMs -Extracellular Matrix -Specialized cell junctions.
38
Describe the roles of microfilaments:
1) Allow the cell or part of it to move. 2) Determine and stabilize the cell shape. They are assembled by actin monomers.
39
Describe sugar phosphate
A phospate group is added to an hydroxyl group.
40
Describe the 3rd law of thermodynamics:
The entropy, S, of a perfect crystal at the absolute zero is 0.
41
What are polymers?
Polymers are long molecules constructed by the repetition of simple units called monomers.
42
What are polymers?
Polymers are long molecules constructed by the repetition of simple units called monomers.
43
Describe what happens at the half life of 1st order reactions:
For 1st order reaction the half life remain constant with time.
44
Describe the second law of thermodynamics:
The enthropy of an isolated system increase for any spontaneous change.
45
Why do only specific target cells respond to a hormone?
Because only target cells have receptors for binding with that particular hormone.
46
How are monosaccharides divided according to the number of carbon atoms?
-3 carbon sugars (Glyceraldehyde) -Pentoses: They have 5 carbon atoms -Hexoses: Structural isomers with 6 carbons and general structural formula C6H12O6.
47
Describe the cyclic structure of monosaccharides
The ring structure is more common and stable. It's formed when the hydroxyl group of the fifth carbon reacts with the carbonyl group. It shows a novel functional group: the hemiacetal group.
48
What is reduction?
Reduction is gain of electrons.
49
Describe diffusion down an electrical gradient:
A difference in charge across two adjacent areas promotes the movements of ions toward the area with opposite charge.
50
What is the diffusion limit?
The rate of a reaction if every collision by a reactant molecule resulted in the reaction producing the product.
51
Describe spatial summation:
At least two presynaptic neuron fire together and their excitatory presynpatic potential sum up.
52
Describe the pituitary gland:
Is a small endocrine gland located in a bony cavity at the base of the brain just below the hypotalamus.
53
What is the function of membrane-bound enzymes?
They control specific chemical reactions.
54
What's the half life of a reaction?
The time taken for a concentration of a given reactant to reach half of its value.
55
Describe inhibition:
An inhibitory synapse has a reverse potential below threshold so it keeps Vm lower.
56
What are the three major roles of Sertoli's cells?
-They provide nutrients for the developing sperm. -They form a bloo-testes barrier. -Provide a regulated fluid which allows later stages of development of sperm.
57
What are thee factors that influce the plasma concentrations of hormones:
1) The hormone rate of secretion into the blood. 2) The rate of metabolic activation or conversion. 3) For lipophilic hormones the extenct of binding to the plasma membrane. 4) Its rate of removal from the blod by metabolic inactivation and excretion in the urine.
58
How is genetic information encoded in the DNA?
Is encoded as the sequence of bases.
59
Why are CAMs important?
Because they hepl regulating cell shape, growth and differentiation and allow the cell to adapt to its immediate sorroundings.
60
Describe the relation between exergonic and endergonic reactions in human body.
In human body, Gibbs free energy released by exergonic reaction is used to force endergonic reactions.
61
What are the three roles of carbohydrates?
1- They are a source of energy 2- They can transport energy in complex organisms 3- The serve as carbon skeleton for other molecules.
62
What are the properties of spontaneus reactions?
Spontaneus reaction occurs without the input of energy and once started they proceeds to completion.
63
What does mestruation marks?
The beginning of both uterine and ovarian cycles.
64
Describe the peacemaker activity:
The membrane potential slowly depolarize showing a peacemaker potential, until it reaches the threshold and an action potential is then generated.
65
Describe kinesin:
It carries protein laden vesicles from one part to another walking along a microtubule by a repeated series of shape changes.
66
If Km is small...
The substrate binds strongly to the active site and the substrate is readily converted to products, even at low substrate concentration
67
Describe saturated fatty acids:
The alkyl chain contains only C-C single bonds and it's a straight line. They pack together tightly due to Van der Waals forces and thus they're solid at room temperature and have higher melting points. Animal fats.
68
What are the 3 types of system?
1) Open system 2) Closed System 3) Isolated system
69
What are the three different types of fatty acids?
1-Saturarted 2-Monounsaturated 3-Polyunsaturated
70
Describe viviparity:
Animals retain the embryo within the mother's body.
71
What's the difference between ribose and deoxyribose?
Deoyribose sugar differs from Ribose sugar in Lacking an Oxygen atom at the 2nd carbon position.
72
What's the tendency of ΔS?
ΔS tends to be positive due to random thermal motion at molecular level.
73
What are the two different kinds of membrane carbohydrates?
Glycoproteins and glycolipids and they form the glycocalix.
74
Describe the plant cell wall and its major roles:
Is a semirigd structure outside the plasma membrane with 3 major roles: 1) It provides support for the cell and limits its volume by remaining rigid- 2) It acts as a barrier to infection of fungi and other disease causing microorganisms. 3) It contributes to plant form by growing as plant cells grow.
75
What are the two main functions of excretory organs?
1) Osmoregulation. 2) Secrete waste product while reabsorbing valuable filtered solutes.
76
What is endocrinology:
The study of homeostatic chemical adjustment and other activites accomplished by hormones.
77
Why is Km important?
It tells us about the strength of the interaction between the substrate and the enzyme.
78
What's work?
Work is energy dispersed as non random motion
79
How is the ester linkage formed?
Through a condensation reaction between the carboxyl group of the fatty acid and a hydroxyl group of the glycerol.
80
What are the two types of energy?
1) Kinetic Energy 2) Potential Energy (Gravitational and chemical)
81
Describe chemoheterotrophs
The energy source of chemoheterotrophs are chemical bonds and the carbon source are organic compounds.
82
What are the main characteristics of circulation in crocodilians?
-Two complete separated ventricle, they have two aortas. -When is breathing the resistance in pulmonary circulation is low and so all the blood flow in the pulmonary circuit. -When is not breathing polmunary vessles constrict and blood from the right ventricle flow from Aorta.
83
Describe Glycerophospholipids:
They have a backbone of glycerol just like triglycerides but they differ because one of the three fatty acids is replaced with a phosphodiester group.
84
State the functions of the lipid bilayer:
1- It forms the basic sctructure of the plasma membrane 2- Its hydrophobic interior serves as a barrier between the inside and the outside of the cell. 3-It's responsable for the fluidity of the membrane.
85
What are macromolecules?
Macromolecules are polymers with molecular weight exceeding 1000.
86
Describe hypertonic condition:
The osmolarity of the inside is lower than the osmolarity of the outside therefore water diffuse out of the cell causing the cell to shrink.
87
Describe endocytosis:
The plasma membrane pinch-off forming a membrane-enclosed vesicle so that the engulfed material is trapped within the cell.
88
Progesterone always...
Inhibits
89
What is the two possible structural configuration of monosaccharides?
-Straight chain -Ring (Cyclic)
90
What are the roles of the cytoskeleton?
It support the cell and help it maintains its shape. It holds organeless in their position or move them. It interacts with the extracellular structures, helping anchor the cell in place.
91
What does selectively permeable means?
That the plasma membrane permits some particles to pass through while excluding other particles.
92
What are the three different kind of polysaccharides?
-Starch -Glycogen -Cellulose
93
Describe the rate of the reaction:
The rate of the reaction describe how fast does a reaction occurs (how fast the concentration of reactants decrease and the concentration of products increase)
94
What is a sinatrial node (SN)?
Is a cluster of autorhytmic cells located on the wall of the right atrium where the action potential is generated.
95
What is the main role of ADH?
To control the amount of fluid loss in the urine.
96
Describe the function of the posterior pituitary:
Is an extension of the hypotalamus. It doesn't produce any hormone, it simpy stores and releases vasopressin and oxytocin.
97
Describe efferent neurons:
Carry instructions to effector organs.
98
Describe peripheral membrane proteins:
Polar molecules that don't penetrate the membrane, instead they adhere tightly to the cytoplasmic or extracellular surface.
99
What are the two kinds of active driving forces?
-Carrier mediated transports -Vesicular transport
100
What are lipids?
Hydrocarbons insoluble in water because they are non-polar.
101
Describe oviparity:
The animal lays eggs in the environment and their embryos develop outside their mother body.
102
Describe vesicular transport:
Requires energy for vesicle formation and movement outside the cell.
103
Illustrate the cell theory by Schleiden and Schwann
-Cells are the basic structural and physiological units of all organisms. -Cells are both distinct entities and buildin blocks of more complex organisms.
104
What are the two functions of DNA that constitute the central dogma of molecular biology?
1- DNA can repdroduce itslef (Replication). 2- DNA copies its information into RNA (transcription) and RNA can specify a sequence of amino acids in a polypeptide (translation).
105
What are channels?
Water filed pathways that serve as conduits that allow water molecules and ions to flow passively through the lipid bilayer.
106
What are the two kinds of bases?
**Py**rimidines (CUT the **Pie**) and **Pur**ines (**Pure** As Gold).
107
What is the overall process of sexual reproduction?
Require the joining of two haploid cells (gametes) to form a diploid zygote.
108
Describe steroids:
Tetracyclic compounds made up of a series of alkyl rings linked by shared carbon.
109
How are lipophilic hormones transported into the blood?
They cannot dissolve in blood and are therefore bound to specific proteins.
110
Describe phototrophs in general
Phototrophs capture energy from the sun and use it to oxidise H2O or H2S to release high energy electrons.
111
Describe anabolism and its characteristics
Anabolism is a process by which large and complex molecules are built up from smaller components. -Biosynthetic and reductive -Energy is required to create bonds -Diverging
112
Describe dynamic equilibrium:
A dynamic equilibrium which can be described as the probability of molecule being at one state or another at any given time.
113
What are the two characteristics of oligosaccharides?
They may have additional functional groups which give them special properties and they may be covalently bonded to proteins and lipids on the cell surface acting as recognition signals.
114
Describe the 1st law of thermodynamics:
The internal energy of an isolated system is constant
115
What are the 6 events of fertilization?
1) The egg and sperm must chemically recognize each other 2) The sperm is activated, enabling it to gain access to the plasma membrane of the egg. 3) The plasma membrane of the egg fuses with the Plasma membrane of the sperm. 4) The egg blocks entry of additional sperm 5) The egg is metabolically activated and stimulated to start development. 6) The egg and sperm nuclei fuse to create the diploid nucleus of the zygote.
116
What are the two kinds of bases?
**Py**rimidines (CUT the **Pie**) and **Pur**ines (**Pure** As Gold).
117
What are the two types of cardiac cells (describe them)
1) Contractile cells: don't initiate the action potential and they do the mechanical work of pumping the blood out. 2) Autorhythmic cells: don't contract, they initiate and conduct the action potential and they display a peacemaker activity.
118
What are the two forms of active transport?
-Primary active transport -Secondary active transport
119
What are the two types of passive forces?
-Diffusion down a concentration gradient -Diffusion down an electrical gradient
120
Describe Na+-K+ pump roles:
-It helps estabilish the Na+ and K+ concentration gradient across the plasma membrane. -It regulates the cell volume by controlling the concentration of solutes inside the cell. -The energy used to drive the pump indircetly serves as energy for secondary active transports.
121
Describe cell adhesion molecules (CAM)
They can either protrude from the outer membrane surface and form hooks and loops or span the plasma membrane where they serve as structural link between the outer membrane surface and its extracellular sorroundings.
122
Describe flagella in prokaryotic cells:
A complex motor protein spins a flagellum made of flagellin on its axis like a propeller.
123
How are marine fishes compared to their environment?
They're hyposomotic which means higher internal concentration of water but lower internal concentration of salt. Salt will tend to diffuse into the body whereas water will tend to flow out.
124
If ΔG is negative...
The reaction is spontaneous
125
What is a nucleotide?
A unit of the polynucleotide composed of a nucleoside (a sugar and an amino base) and a phosphate group.
126
Describe ammonia:
Is toxic, freely soluble in water and easily removed across skin and gills in aquatic animals.
127
What's sorrounding?
Sorrounding is everything else in contact with the system.
128
Describe monosaccharides
They are single and simple sugar used to assemble larger polymers.
129
Describe photoheterotrophs
The energy source for photoheterotroph is the sun and the carbon source are organic compoounds.
130
What are transmembrane proteins?
They are integral proteins that extend through the entire thickness of the lipid bilayer one or several times.
131
132
Describe the function of dynein:
Motion of cilia and flagella results from the sliding of the microtubules doublets past each other and this movement is driven by dynein.
133
Where is the AP conducted once is generated?
-It is conducted across the atrium through using the interatrial pathway. -It is conduceted across the ventricles through th atriventricular line.
134
What is summation?
Graded potential can summate to reach threshold.
135
Describe the outer membrane of mitochondria
The outer membrane is permeable to most molecules and this is why the intermembrane space has similar characteristics to the cytoplasm.
136
What are polysaccharides?
Polymers of hundreds or thousands of monosaccharides.
137
Describe the anterior pituitary:
Consists of glandular epithelia tissue which are then released in response to hypophysiotropic hormones.
138
Describe chemotrophs in general:
Chemotrophs oxidise organic compounds to release high energy electrons.
139
What's Michaelis Constant (Km)?
Is the concentration of substrate required for an enzyme to operate at half its maximum velocity.
140
What are the four kind of biomolecules?
-Proteins -Carbohydrates -Lipids -Nucleic Acid
141
What are the three different kind of polysaccharides?
-Starch -Glycogen -Cellulose
142
What are docking marker acceptors?
They are located on the inner membrane surface and allow the docking of vesicles for exocytosis
143
Describe the third stage of metabolism:
The acetyle group of Acetyl CoA enter the Kreb's cycle where it is completely oxidise to CO2 and H2O.
144
What are the 5 parameters that affect Flick's Law of Diffusion?
1) The magnitued of the concentration gradient 2) The surface of area across which diffusion takes place 3) The lipid solubility of the substance. 4) Molecular weight of the substance 5) Distance through which diffusion must take place (thickness of the membrane).
145
What does bond breaking do?
Bond breaking consumes energy
146
What's Boltzman probability?
Is the probability that the system will have an enthalphy H at a specific temperature T.
147
What are nucleic acids?
Polymers of four different kinds of nucleotide specialized in the storage and transmission of genetic information.
148
Describe starch:
Is a polysaccharide of glucose linked by α-glycosidic linkages. It's the principal energy storage in plants.
149
What are the three ways to describe oxidation?
1) Oxidation is joining with an Oxygen 2) Oxidation is losing an hydrogen 3) Oxidation is losing an electron
150
What are the four kind of biomolecules?
-Proteins -Carbohydrates -Lipids -Nucleic Acid
151
Why are the chains of fatty acids hydrophobic?
Because they contain C-H and C-C bonds which have low electronegativity and are nonpolar.
152
What are the two forms of active transport?
-Primary active transport -Secondary active transport
153
If ΔH is positive...
If ΔH is positive the reaction is endothermic, the system acquire energy and become less stable.
154
What are the 3 means of control of hormone secretion:
1) Negative-feedback control. 2) Neuroendocrine reflexes 3) Diurnal (circadian) Rhythms.
155
What are the 5 functions of the extracellular matrix:
1) Holds the cell tissue in position. 2) It contributes to the physical properties of cartilage. 3) It helps filter materials passing between different tissues. 4) It helps orienting the cell movements during embryonic development. 5) It plays a rle in chemical signalling between cells.
156
Describe regeneration:
Pieces of organism can regenerate complete individuals
157
What's endergonic reaction?
A reaction that requires Gibbs free energy (ΔG\>0). It's non spontaneous and reactants favored.
158
What is an action potential?
A sudden change in Vm due to movement of ions.
159
State three aspects that affect the efficiency of these transport:
1) Specificty 2) Saturation 3) Competition
160
What happen in case of water deprivation?
Water deprivation results in an increase in osmolarity which stimulate the hypothalamus to produce more ADH.
161
What does Enthalphy measures?
Enthalpy measures the energy change in a system.
162
What's a phosphodiester group?
Is a phosphate group modified by the addition of different substituent group.
163
Describe desmosomes:
Adhering jucntions that anchor cells together.
164
What are oligosaccharides?
Polymers of 3 to 20 simple sugars.
165
What happens to phospholipids in acqueous environment?
They thend to form a lipid bilayer.
166
What happens during the first 12 days of ovarian cycle?
Estrogen exerts negative feedback on gonadotropin release.
167
What are the two main kind of hormones based on their chemical classificatio?
1) Hydrophilic 2) Lipophilic
168
What are the three different type of cell junctions?
1) Tight junctions 2) Gap Junctions 3) Desmosomes.
169
What are the two forms of carrier-mediated transport:
1) Facilitated diffusion. 2) Active transport.
170
Describe oxidative phosphorylation
High energy electrons are used to reduce O2 and H2O and this energy is used to create an electrochemical gradient across the membrane that then generates the energy required to synthesise ATP.
171
How are hydrophilic hormones transported into the blood?
They simply dissolve in blood.
172
What are the two types of respiration?
-Internal respiration: Generate ATP -External respiration: Provides the O2 and remove CO2
173
If Km is large...
The substrate binds less strongly to the enzyme and needs high concentration of substrate to catalyse effectively the formation of products.
174
Describe monounsaturated fatty acids:
Their alkyl chain contains one C=C double bond that causes the structure to bend.
175
What are the two units that constitute a desmosome:
A pair of plaques and a strong filament containing cadherin that extend across the space between the two cells attaching the plaques at both sides.
176
What's a phosphodiester group?
Is a phosphate group modified by the addition of different substituent group.
177
Describe statistical thermodynamics:
It also consider microscopic properties of matter and it refers to the probabilities of things happening at a molecular level.
178
What's internal energy?
Internal energy is the total energy within a system
179
An inorganic or organic compound or ion that is required by an enzyme before the enzyme can catalyze its reaction is called a...
**cofactor**
An example of a cofactor is NAD+
180
Describe vesicular transport:
Requires energy for vesicle formation and movement outside the cell.
181
If ΔH is negative...
If ΔH is negative the reaction is exothermic, system loses energy and become more stable.
182
What is neurotransmission?
The process that generates action and graded potential.
183
Describe compotetition of carrier mediated transports:
Several closelsy related compounds may compoter for the same carriers and the presence of both diminishes the rate of transfer of either.
184
What are the reason for the drop from 160mmHg to 100mmHg from the atmosphere to the lungs?
1) The airways are moist, the air from the outside become saturated with water reducing the partial pressure. 2) Fresh inspired air is mixed with a volume of air from the previous breath
185
What are docking marker acceptors?
They are located on the inner membrane surface and allow the docking of vesicles for exocytosis
186
What are electron carriers?
Are intermediate of redox reaction in the metabolic pathways of the cell.
187
What are the two stages of the chemiosmotic process?
Electron transport and ATP synthesis \*Oxidative phosphorylation).
188
How is energy stored in the chemiosmotic gradient used to synthesize ATP?
Protons flow back through ATP synthase causing the rotor to turn and such a conformation change lead to ATP synthesis.
189
How are monosaccharides divided according to the number of carbon atoms?
-3 carbon sugars (Glyceraldehyde) -Pentoses: They have 5 carbon atoms -Hexoses: Structural isomers with 6 carbons and general structural formula C6H12O6.
190
Describe the 0 law of thermodynamics:
If the body A is in thermal equilibrium with the body B and the body B is in thermal equilibrium with body C then the body A is in thermal equilibrium with the body C.
191
What are carotenoids?
Lipids that act as light absorbing pigments.
192
Describe Non-competitive inhibition:
Occurs when binding of an inhibitor affects the catalytic rate rather than the binding affinity of for the substrate. The substrate and the inhibitor bind at different site on the enzyme.
193
What happens to phospholipids in an aqueous environment?
They tend to form a lipid bilayer with hydrophilic heads pointing outward. The water is excluded from the hydrophilic core.
194
Describe endocytosis:
The plasma membrane pinch-off forming a membrane-enclosed vesicle so that the engulfed material is trapped within the cell.
195
Describe the peculiarity of the outward movement of K+
It moves outward because concentration gradient exceed electrical gradient.
196
What are the two types of passive forces?
-Diffusion down a concentration gradient -Diffusion down an electrical gradient
197
Describe the ascending and descending components of the countercurrent system:
Filtrate in the descending limb become progressively more concentrated as it loses water. The ascending filtrate pumps out salt and become hyposmotic.
198
Describe the three key steps of spermatogenesis:
1) Initial proliferation of male germ cells into spermatogonia proceeds by mitosis. 2) Primary spermatocytes undergo the first meiotic division to form secondary spermatocyte. 3) Second meiotic division produces four haploid spermatids for each primary spermatocyte.
199
Describe complementary base pairing:
Thymine will always pairs with Adenine, forming two hydrogen bonds. Guanine will always pair with Cytosine forming three hydrogen bonds.
200
What is the main function of the contraction of the heart?
It create a pressure gradient required to move blood along the vessels.
201
Describe paracrines:
Local chemical messengers whose effect is exerted only on neighbouring cells in the immediate sorroundings of the receptors.
202
What happens if the membrane is permeable to a molecule
Molecules move down their concentration gradient (from high concentration to low concentration).
203
Why are enzyimes highly specific?
Because the shape of the cleft is complementary to the shape of the substrate so that only the substrate can fit into it.
204
If reduction potential is less than zero (is negative)...
It means that the reduced form of the compound has lower affinity for electrons than hydrogen.
205
What's a reaction mechanism?
A reaction mechanism is an educated guess about the way a reaction occurs
206
What is the reaction from which macromolecules are usually broken down?
Hydrolisis breaks down polymers to their simple units by adding water to the system (energy is released)
207
What are the two components of the extracellular matrix:
1) A fibrous protein called collagen. 2) A matrix of glycroproteins.
208
What is the typical movement of K+ at resting membrane potential?
It flows outward, causing hyperpolarization.
209
Why are glycogen and cellulose good at storing energy?
Because they can both be hydrolized readily into glucose monomers which is then broken down to release energy.
210
Describe the electron transport
Electron from NADH enter complex I while electrons from FADH2 enter complex II. Electrons are then handed down from higher to lower redox potentials and finally they are transfere to O2 to form H2O.
211
What's Gibbs free energy?
Gibbs free energy is the energy produced which is free to do work.
212
What are the 5 components of the endomembrane system?
1) The plasma membrane 2) Nuclear envelope 3) Endoplasmic reticulum 4) Golgi Apparatus 5) Lysosomes and vacuoles.
213
Why are phospholipids amphipathic?
Because the two fatty acids tails are hydrophobic (repel water and tend to aggregate) while the phosphate functional group has a negative electric charge thus it's hydrophilic.
214
What is a hormone?
A chemical mediator that is secreted by endocrine cells into the blood, where it is then transported to target cells.
215
How are freshwater fishes compared to their environment?
They are hyperosmotic which means they have lower internal concentratio of water but higher internal concentration of salt. Water will tend to flow in whereas salt will tend to flow out.
216
What are Vitamins?
Small molecules that cannot be synthetized by the body and must be acquired in diet.
217
Describe symport:
Solute and Na+ move in the same direction.
218
Describe carrier mediated transports:
A carrier protein spans the thickness of the plasma membrane and undergoes specific conformational change that allow the transport of substances.
219
What are the three ways by which CO2 is transported in the blood?
1) As bicarbonate ions (70%) 2) Binded with hemoglobin (20%) 3) Carried in a solution of plasma (5%).
220
What are the two roles of the membrane sorrounding the organelles in the eukaryotic cells?
1) Keeps the organelle's molecules away from other molecules in the cell, to prevent inappropriate reactions. 2) Act as a traffic regulator, letting important raw material into the organelle
221
Describe desmosomes:
Adhering jucntions that anchor cells together.
222
If ΔG is positive....
The reaction is non-spontaneous.
223
What are glycolipids?
Lipids that contain a sugar group instead of a fatty acid.
224
What are amines and how are they divided?
Amino-acid derivates and can be either catecholamines or indoleamines.
225
Why are glycogen and cellulose good at storing energy?
Because they can both be hydrolized readily into glucose monomers which is then broken down to release energy.
226
What are the five functions of vacuoles:
1) Storage 2) Structure 3) Reproduction 4) Digestion 5) Contractile vacuoles.
227
What's metabolism?
All the chemical changes as food nutrients are processed by an organism to release Gibbs free energy and form complex chemicals constituent of the living cell.
228
How do lipophilic hormones alter cell's proteins/function?
They function mainly by activating specific genes in target cell to cause formation of new intracellular proteins which in turn produce the desired effect.
229
Why are phospholipids amphipathic?
Because the two fatty acids tails are hydrophobic (repel water and tend to aggregate) while the phosphate functional group has a negative electric charge thus it's hydrophilic.
230
Describe polyunsaturated fatty acids:
Their alkyl chain contain more than one C=C double bond and thus they are bent. They cannot pack together and they're liquid at room temperature and have lower melting point. Plant oils.
231
State all the characteristics of RNA;
-Its pentose sugar is ribose. -It has Uracil as a base instead of Thymine. -RNA is single-stranded.
232
Describe afferent neurons:
Inform the central nervous system about condition of both internal and external environment.
233
Describe microtubules:
The large diameter components of the cytoskeleton. 1) They form a rigid internal skeleton. 2) They act as a framework along which moto proteins can move.
234
What are the two factors that determine the membrane potential of the cells?
-Selective permeability to certain ions -Concentration gradient of permeant ions across the membrane.
235
What are the four components of negative-feedback control?
1) Variable, which is detected by a 2) Sensor. The information is then sent to 3) Integrator which compare the desired value to the actual value and if the value is not correct the 4) effector will generate a stimulus to modify the variable.
236
What is osmosis?
The net diffusion of water down its concentration gradient through a selectively permeable molecule.
237
What is the nuclear envelope?
Is a double membrane that separates the DNA from the cytoplasm.
238
Describe hypotonic condition:
The osmolarity of the inside is greater than the osmolarity of the outside therefore water diffuse into the cell and the cell swell.
239
What's the difference between ribose and deoxyribose?
Deoyribose sugar differs from Ribose sugar in Lacking an Oxygen atom at the 2nd carbon position.
240
Describe the features of the chloroplasts:
They contain the green photopigment chlorophyll and are the sites of photosynthesis.
241
Describe secondary active transport:
Energy is required but not used directly to produce movement against concentration gradient. The transfer of a solute across the membrane is coupled with the transfer of the ion that supplies the driving force.
242
What are the two kinds of membrane proteins?
1- Integral membrane proteins 2- Peripheral membrane proteins.
243
What are the two functions of DNA that constitute the central dogma of molecular biology?
1- DNA can repdroduce itslef (Replication). 2- DNA copies its information into RNA (transcription) and RNA can specify a sequence of amino acids in a polypeptide (translation).
244
What are the two main kinds of hypophysiotropic hormones?
-Stimulatory -Inhibitory.
245
What's a catalyst?
A catalyst is a chemical species that lower the activation energy barrier, speeding up the rate of the reaction and it's itself unchanged at the end of the reaction.
246
What is the mechanism that freshwater fishes developed to cope with their environment?
They have to conserve salt concentration by uptaking salt from the environment and they produce a lot of diluted urine.
247
What is copulation? (Sohaib has to answer this question, no matter whose turn is)
The physical joining of male and female accessory sex organs.
248
Why are progesterone and estrogen crucial?
-For the maintainance of the uterine lining -They send negative feedback to the anterior pituitary to inhibit gonadotropin release.
249
Describe cellulose:
Is a polysaccharide of glucose with β-glycosidic linkages, thus is more stable and an excellent structural component. Is the major component of plant cell wall.
250
What are the two forms of vesicular transport?
1) Exocytosis 2) Endocytosis
251
What are waxes?
Highly nonpolar and impermable compound that are plastic at room temperature.
252
What is Metabolism?
Metabolism is the sum of all biochemical reactions taking place in the cell (the sum of all anabolic and catabolic reactions)
253
What are macromolecules?
Macromolecules are polymers with molecular weight exceeding 1000.
254
What is the function of membrane-bound enzymes?
They control specific chemical reactions.
255
What are the three different forms of cell adhesion?
-CAMs -Extracellular Matrix -Specialized cell junctions.
256
What are the two different kinds of membrane carbohydrates?
Glycoproteins and glycolipids and they form the glycocalix.
257
What is a lipid bilyaer?
Is a double layer of lipid molecules with an hydrophobic inner core.
258
What is respiratory homeostasis?
Systems monitor and responds to any chanes in the partial pressure of gasses.
259
Describe active transport
It requires energy to transfer molecules against the concentration gradient.
260
What are fatty acids?
They are long nonpolar hydrocarbon chains and have an acidic polar carboxyl group.
261
Describe diurnal (circadian) rhythms:
The secretion rates of many hormones fluctuate up and down as a function of time.
262
What generates the upstroke of the action potential?
The upstroke is generated by an entrance of Na+ that cause a depolarization.
263
What are carotenoids?
Lipids that act as light absorbing pigments.
264
What are the three components of any cardiovascular system?
1) A muscular pump (the heart) 2) A fluid (blood) 3) A series of conduits (blood vessels)
265
What are carriers?
They can either facilitate the trnasport of a specific molecules or couple transport of a molecule with the transport of a solute
266
What happens when the AP leaves the atriventricular line?
It's conducted down the bundle of His which goes down through the septum. The bundle of His then subdivide into Purkinje fibers that conduct the action potential to the ventricular muscle causing it to contract.
267
Describe integral membrane proteins:
They are noncovalently embedded in the phospholipid bilayer by their hydrophobic regions.
268
What are glycolipids?
Lipids that contain a sugar group instead of a fatty acid.
269
What happens if the membrane is impermeable to a molecule
No diffusion takes place across the membrane even if a concentration gradient exists.
270
What are the four components of all neurons?
-An input region (Dendrites) -An integrative region (Soma and axon hillock) -A conductile region (Axon) -An output region (Axon terminals)
271
What are carriers?
They can either facilitate the trnasport of a specific molecules or couple transport of a molecule with the transport of a solute
272
Describe the structure of the lipid bilayer
It has a trilaminar structure with the hydrophobic tails buried in teh centre of the bilayer away from water and the hydrophilic heads lined up on both sides in contact with water.
273
What are final electron acceptors?
The final product of a metabolic pathway that allows the regeneration of electron carriers.
274
Describe catabolism and its characteristics
Catabolism is the process by which large molecules are decomposed into smaller molecules. -It is degradative and oxidative -It liberates energy stored in the bonds of large molecules -Converging
275
What is osmolarity?
The concentration of osmotically active particles present in a solution.
276
What is the effect of parasympatetric stimulation?
The heart rate decrease due to two effects: 1) Hyperpolarisation of the SA node. 2) Decrease the rate of spontaneous depolarisation
277
What are the two important implications of the cell theory?
1) Studying cell biology is the same as studying life. 2) Life is continuous: all cells in our body come from a single cell.
278
Why is catabolism converging?
Because a great variety of different compounds re used to produce the same products.
279
Describe hypotonic condition:
The osmolarity of the inside is greater than the osmolarity of the outside therefore water diffuse into the cell and the cell swell.
280
Describe the characteristics of an open circulatory system:
The extracellular fluid is the circulatory fluid and is called hemolymph. Hemolymph leaves the vessels of circulatory system, percolate through the cells and tissues and then flow back into the vessels.
281
What are passive driving forces?
Forces that do not require cells to spend energy to produce movement.
282
What happens if the membrane is impermeable to a molecule
No diffusion takes place across the membrane even if a concentration gradient exists.
283
State all the characteristics of RNA;
-Its pentose sugar is ribose. -It has Uracil as a base instead of Thymine. -RNA is single-stranded.
284
How do marine vertebrates cope with excess of salt int their bodies?
They excrete the excess of salt through their kidneys and through salt glands.
285
What are the 4 parameters that affect diffusion?
1- Size of the molecules 2- Size of the sorroundings 3- Shape of the molecules and temperatures 4- Diffusion coefficient
286
What is a glycosidic link?
A glycosidic link is the result of a condensation reaction between a hydroxyl group on one sugar and a hydroxyl group on another sugar.
287
What is DNA?
Deoxyribonucleic acid, a polynucleotide that encodes hereditary information and passes it from generation to generation.
288
Why are cells small?
Small cell size is a practical necessity arising from the change in the surface area-to-volume ratio.
289
Describe photoautotrophs
The energy source of photoautotroph is the sun and the carbon source is CO2.
290
State three aspects that affect the efficiency of these transport:
1) Specificty 2) Saturation 3) Competition
291
Describe parthenogenesis:
Development of unfertilized eggs.
292
State all the characteristics of the nucleus:
-It contains the chromosomes -It is bounded by the nuclear envelope. -Is the location od DNA replication and transcription.
293
Describe specificty of carrier mediated transports:
Each carrier is specialise to transport specific substances.
294
Describe polyunsaturated fatty acids:
Their alkyl chain contain more than one C=C double bond and thus they are bent. They cannot pack together and they're liquid at room temperature and have lower melting point. Plant oils.
295
What are the main characteristics of circulation in fishes?
Fishes have 4 chambers. -An atrium recevise blood from the body and pumps it into the ventricle -The ventriclule pumps blood to the gills where gases are exchanged. -Gasses are then collected in the aorta. -Unidirectional
296
Describe graded potential:
It doesn't travel as far as action potential, instead it dissipates due to current leaks out of the axon. It can reach threshold (and thus fire AP) only if summated.
297
What are the 6 different functions of hormones:
1) Regulating metabolism, water and electrolyte balance. 2) Inducing adaptive changes to help the body cope with stressful situations. 3) Promoting smooth, sequential growth in development. 4) Controlling sexual differentiation and development.
298
What are aquaporins?
Specific channels for water located on the plasma membrane
299
What are the 4 different kind of carbohydrates according to the number of monomers?
1-Monosaccharides 2-Disaccharides 3-Oligosaccharides 4-Polysaccharides
300
What's tonicity?
The effect that a solution has on the cell volume.
301
Describe tight junctions:
Adjacent cells bind firmly with one another at points of direct contact to seal of the passageway betweent cells.
302
What is gas solubility:
How soluble a gas is within the body.
303
Describe specificty of carrier mediated transports:
Each carrier is specialise to transport specific substances.
304
Describe the cyclic structure of monosaccharides
The ring structure is more common and stable. It's formed when the hydroxyl group of the fifth carbon reacts with the carbonyl group. It shows a novel functional group: the hemiacetal group.
305
Describe the synthesis of ADH:
Is produced in the supraoptic nuclei in the hypothalamus as a pre-prohormone and is then store in the posterior pituitary.
306
Describe exocytosis:
Membrane enclosed vesicles formed within the cells fuse with the plasma membrane releasing its content to the exterior.
307
State all the characteristics of DNA:
1- Its pentose sugar is deoxyribose. 2-It's double-stranded and the two strands form a double helix and are antiparallel (they run in opposite direction).
308
Describe monounsaturated fatty acids:
Their alkyl chain contains one C=C double bond that causes the structure to bend.
309
Why are the chains of fatty acids hydrophobic?
Because they contain C-H and C-C bonds which have low electronegativity and are nonpolar.
310
Describe the function of juvenile hormone:
Is release continously and as long as it's present the insects molt into another juvenile individual.
311
Describe Na+-K+ pump roles:
-It helps estabilish the Na+ and K+ concentration gradient across the plasma membrane. -It regulates the cell volume by controlling the concentration of solutes inside the cell. -The energy used to drive the pump indircetly serves as energy for secondary active transports.
312
What are the three roles of carbohydrates?
1- They are a source of energy 2- They can transport energy in complex organisms 3- The serve as carbon skeleton for other molecules.
313
Describe compotetition of carrier mediated transports:
Several closelsy related compounds may compoter for the same carriers and the presence of both diminishes the rate of transfer of either.
314
What are the other roles for nucleotides?
-ATP (Energy transducer in biochemical reactions) -GTP (Energy source in protein synthesis) -cAMP (Essential to the action of hormones and transmission of information in the nervous system).
315
Describe uric acid:
Nitrogenous end product of protein metabolis and is a semisolid excreta.
316
What are driving forces?
Even if a particle can permeate the membrane or pass trhough a channel some force is needed to move it across the membrane.
317
What's a cleft?
The site at which the substrate binds to the enzyme
318
What are the two distinct forms of secondary active transport?
Symport and Antiport.
319
Describe the inner membrane of mitochondria
The inner membrane is impermeable to most molecules and contain proteins for the electron transport chain
320
Describe the second stage of metabolism:
In the second stage of metabolism, the small molecules produced in the previous stage enter the cell and are converted into a small number of simple molecules. The products of this stager are: 2-Carbon Acetyl CoA and some ATP.
321
Describe open system:
Open system can exchange both energy and matter with the sorroundings
322
What are the two kinds of active driving forces?
-Carrier mediated transports -Vesicular transport
323
What are driving forces?
Even if a particle can permeate the membrane or pass trhough a channel some force is needed to move it across the membrane.
324
Describe budding:
New individuals are formed as the outgrowth or buds from the body of older animals
325
What's energy?
Energy is the capacity to do a work.
326
Describe chitin:
A polymer of N-acetylglucosamine.
327
Describe glycogen:
Is a polysaccharide of glucose and the form of energy storage in animals. Is water-insoluble and resist osmotic pressure.
328
State the seven functions of membrane proteins:
1) Ligand Binding Receptor 2) Cell Adhesion Molecules (CAM) 3) Channels 4) Carriers and pumps 5) Membrane-bound enzymes 6) They participate to intracellular signaling 7) Docking marker acceptor
329
What are transmembrane proteins?
They are integral proteins that extend through the entire thickness of the lipid bilayer one or several times.
330
What is the evolutionary tendency of closed circulatory systems?
is toward a separation between the oxygenated and deoxygenated blood and respective circuits.
331
Why do NADH and FADH2 need to be re-oxidised?
Because they're present in small amount to is important to recycled them in order to keep the metabolism in function.
332
What are the two units that constitute a desmosome:
A pair of plaques and a strong filament containing cadherin that extend across the space between the two cells attaching the plaques at both sides.
333
State and describe the two different membranes of the mitochondria:
-Outer membrane: small and protective and not really selective. -Inner membrane: much more selective and contains proteins that participate in cellular respiration.
334
What are the three different types of tonic condition?
-Isotonic -Hypotonic -Hypertonic
335
What does bond formation do?
Bond formation release energy
336
What are nucleic acids?
Polymers of four different kinds of nucleotide specialized in the storage and transmission of genetic information.
337
What are lipids?
Hydrocarbons insoluble in water because they are non-polar.
338
What's potential chemical energy?
Energy stored in molecules by virtue of their bond.
339
State the three different types of carbohydrates that can be obtained when a functional group is added:
1-Sugar phosphate 2-Amino sugar 3-Chitin
340
How does a fall in blood volume stimulates the production of ADH?
It promotes ADH secretion by stopping depolarization of pressure receptor.
341
Describe urea:
Is soluble ini water, is a product of ammonia detoxification.
342
What are fatty acids?
They are long nonpolar hydrocarbon chains and have an acidic polar carboxyl group.
343
What's a transition state?
Is an high energy species whose chemical character is between reactant and products. Transition state is the highest energy species that exists during the course of the reaction.
344
What are respiratory pigments?
Molecules that binds to O2 where pO2 is high and release it where pO2 is low.
345
What are the three different places where you can find robosomes?
1- Free in the cytoplasm 2- Attached to endoplasmic reticulum 3- Inside the mitochondria and chloroplast
346
What happens in case of water ingestion?
The osmoreceptor on the hypothalamus perceive a decrease of the osmolarity and reduce ADH production.
347
What are the two possible ways in which complementary base pairing can occur in RNA?
1- Between different regions of the same RNA polymer. 2-Between RNA and DNA (Adenine will pair with both thymine and uracil).
348
Describe absolute refractory period:
No stimulus, however strong, can fire a second action potential.
349
Describe the first stage of metabolism
In the first stage of metabolism macromolecules are degraded to their monomeric units. It occurs outside the cell n the process of digestion.
350
What is a hormone?
Is a chemical mediator that is released into the blood by an endocrine cell and is transported by the blood to its specific target cell.
351
What are the two conditions for a non spontaneous reaction to (not) occur?
-Reduction potential has to be negative and ΔG has to be positive.
352
Describe the process of positive cooperativity:
At low pO2 values only one subunit will bind to hemoglobin and this cause the molecule to change its quaternary structure and make it easier for the other subunits to bind to oxygen.
353
Describe the overall function of the endoplasmic reticulum and the golgi apparatus:
Are compartments in which cells in synthesize some proteins.
354
What are the two possible ways in which complementary base pairing can occur in RNA?
1- Between different regions of the same RNA polymer. 2-Between RNA and DNA (Adenine will pair with both thymine and uracil).
355
Describe isotonic condition:
The osmolarity of the inside is equal to the osmolarity of the outside so there's no net movement of water and no change in volume of the cell.
356
What are the two types of driving forces?
Active and passive driving forces.
357
What are the key features of ALL prokaryotic cell?
1- A plasma membrane 2- A nucleoid 3- Cytoplasm
358
State the three different types of carbohydrates that can be obtained when a functional group is added:
1-Sugar phosphate 2-Amino sugar 3-Chitin
359
What are the two things necessary for movement across the membrane?
1) Pathway 2) Driving forces
360
Describe saturation of carrier mediated transports:
A limited number of carrier binding sites are availabel within a particular plasma membrane for a specific substance. This limit is know as the transport maximum.
361
Describe the electrical gradient:
A difference in charge across the membrane resulting from the unbalanced presence of protons (intermembrane space is more positively charged than the matrix).
362
Describe interneurons:
Integrate afferent information and generate afferent response.
363
Where are the receptors of hydrophilic peptides hormoes located?
Since they canot permeate the plasma membrane the bind to specific receptors located on the plasma membrane.
364
What are the three different type of cell junctions?
1) Tight junctions 2) Gap Junctions 3) Desmosomes.
365
What are the two things necessary for movement across the membrane?
1) Pathway 2) Driving forces
366
Describe simple diffusion:
Molecules within a particular species tend to evenly distributed over time.
367
What is a lipid bilyaer?
Is a double layer of lipid molecules with an hydrophobic inner core.
368
What's enzyme inhibition?
Reduction of the rate of an enzyme catalysed reaction.
369
Describe sugar phosphate
A phospate group is added to an hydroxyl group.
370
What is the only way for macromolecules to enter or exit the nucleus?
Through nuclear pores located on the nuclear envelope.
371
Describe amino sugars:
An hydroxyl group is replace with an amino group.
372
What is autorhythmicity?
The contraction of the heart is triggered by an action potential that generate itself.
373
Describe the structure of the lipid bilayer
It has a trilaminar structure with the hydrophobic tails buried in teh centre of the bilayer away from water and the hydrophilic heads lined up on both sides in contact with water.
374
How do hydrophilic hormones alter cell's proteins/function?
Surface-binding hydrophilic hormones function by activating a second messenger pathway. This direction directly alter the activity of pre-existing intracellular proteins to produce the desired effect.
375
What are the three blood conduction that stimulates the production of ADH?
1) Blood pressure 2) Blood volume 3) Cardiac output.
376
Describe saturated fatty acids:
The alkyl chain contains only C-C single bonds and it's a straight line. They pack together tightly due to Van der Waals forces and thus they're solid at room temperature and have higher melting points. Animal fats.
377
What are the two kinds of membrane proteins?
1- Integral membrane proteins 2- Peripheral membrane proteins.
378
What is the resting membrane potential?
Is the electrial potential across the membrane generated by the diffusion of ions down their concentration gradient.
379
What is the mechanism that marine fishes developed to cope with their environment?
Marine fishes have to constantly drink seawater and excrete salt through the gills, the produce a smallo amount of concentrated urine.
380
Describe the nucleus
The nucleus contains most of the cell genetic material.
381
Describe phospholipids:
They have a phosphate group that links a substituent group to a glycerlo unit (this form the hydrophilic and polar head) and two fatty acids chains (that form the hydrophobic and nonpolar tails).
382
What are the three different types of tonic condition?
-Isotonic -Hypotonic -Hypertonic
383
What are the two types of circuits?
-Pulmonary circuit: blood is pumped from the heart to the lungs. -Systemic circuit: blood is pumped from the heart to the rest of the body.
384
Describe the cell wall of the prokaryotic cells:
A robust layer outside the plasma membrane providing structural integrity and protection.
385
Describe the lysosomes:
Lysosomes conain digestive enzymes and they are site where macromolecules are hydrolyzed into their monomers.
386
Describe competitive inhibition:
Competitive inhibitors have a structure that is similar to that of the substrate and binds to the active site of an enzyme to form an enzyme-inhibitor complex.
387
What's the tendency of ΔH?
ΔH tends to be negative due to the natural tendency to fall to lower energy state.
388
What's tonicity?
The effect that a solution has on the cell volume.
389
What are the two conditions for a spontaneous redox reaction to occur?
-Reduction potential has to be positive and ΔG has to be negative.
390
What are the 5 parameters that affect Flick's Law of Diffusion?
1) The magnitued of the concentration gradient 2) The surface of area across which diffusion takes place 3) The lipid solubility of the substance. 4) Molecular weight of the substance 5) Distance through which diffusion must take place (thickness of the membrane).
391
State all the characteristics of DNA:
1- Its pentose sugar is deoxyribose. 2-It's double-stranded and the two strands form a double helix and are antiparallel (they run in opposite direction).
392
Describe Ligand Binding Receptor
Sites that recognize and bind with specific extracellular chemical messengers.
393
State the properties of the lipid bilayer:
1- Is fluid because phospholipids are not held togeterh by covalent bonds. 2- Cholesterlo contributes to both the fluidity and the stability of the membrane. 3- The phospholipids are constantly moving 4- The phospholipid bilayer is impermeable to charged molecules and water soluble molecules.
394
State the two most important differences between the eukaryotic and prokaryotic cells:
-Eukaryotic are larger and prokaryotic cells -Eukaryotic cell contain membrane-bound organelles
395
What is the function of the valves between the chambers?
Prevent the backflow of blood between contraction and rilaxation.
396
Estrogen at high levels...
Stimulates
397
Describe the backbone of DNA and RNA:
Is a chain of sugars and phosphate groups linked by phosphodiester linkages.
398
Describe heat capacity:
Heat capacity is the quantity of heat energy (q) we need to add to the system in order to increase its temperature.
399
What does Entrhopy measures?
Enthropy measures the ways in which energy is distributed within a system.
400
What's an exergonic reaction?
A reaction that release Gibbs free energy (ΔG\<0). It's spontaneous and products favored.
401
Describe lipophilic hormones and how are they divided:
High lipid solube and are poorly soluble in water. They can be either thyroid hormones or steroid hormones.
402
What are the three different types of fatty acids?
1-Saturarted 2-Monounsaturated 3-Polyunsaturated
403
What are the properties of the action of the endocrine system?
Controls process that require duration rather than speed, aimed at maintaing homeostasis.
404
What is the effect of sympathetic stimulation of the heart?
The sympathetic nervous system speeds up heart rate by giving input at the AS node. Noradrenaline is release and cause an accelleration of activation of K channels and this decrease the K permeability. Thresholds is reached much quicker.
405
Describe what happens at the half life of 0th order reaction:
For 0th order reaction the half life decreases as the concentrations of reactants decreases.
406
What are the two distinct forms of secondary active transport?
Symport and Antiport.
407
What are the two gradients formed as a result of electron transport?
1) Chemiosmotic gradient 2) Electrical Gradient
408
What are the other roles for nucleotides?
-ATP (Energy transducer in biochemical reactions) -GTP (Energy source in protein synthesis) -cAMP (Essential to the action of hormones and transmission of information in the nervous system).
409
What is the property of non-spontaneus reactions?
Non-spontaneus reaction require energy to start and proceed.
410
What happens during day 12/14 of the ovarian cycle?
Estrogen exerts positive feedback on the pituitary. This cause a sourge in release of LH.
411
What are the two main components of gas exchange system?
1) Specialized body surfaces area to move gas from environment to the body 2) Mechanisms that ventilate the environment side with air or water and perfuse the internal with extracellular fluid.
412
What are the two main components of extracellular structures in general:
1) A prominent fibrous molecule. 2) A gel like medium in which fibres are embedded.
413
What are triglycerides?
Compound composed of the three carbon alcohol glycerol linked to three fatty acids via ester linkages.
414
What are the two functions of membrane carbohydrates?
1) They act as self identity markers that enable cells to identify and interact with one another. 2) They have a role in tissue growth and prevent cells to trespass across the boundary of neighbouring tissues.
415
Which are the three steps involved in metabolism?
1-Digestion 2-Reduction of small molecules into simple units. 3-Oxidation of acetyl group from Acetyl CoA to form CO2 and H2O (Citric Acid Cycle).
416
Describe chitin:
A polymer of N-acetylglucosamine.
417
What is the electrochemical gradient?
Is the net effect of simultanoeus chemical and electrical gradient on the movement of ions across the membrane.
418
What is degenerancy?
Degenerancy (w) is the number of different way in which the system can adapt to the enthalpy.
419
What are Vitamins?
Small molecules that cannot be synthetized by the body and must be acquired in diet.
420
Describe hypertonic condition:
The osmolarity of the inside is lower than the osmolarity of the outside therefore water diffuse out of the cell causing the cell to shrink.
421
What are aquaporins?
Specific channels for water located on the plasma membrane
422
What are enzymes?
Enzymes are highly efficient and specialized catalysts for one or more chemical reaction in a living system.
423
Describe the two subunits of ATP synthase
F1 subunit protrudes into the mitochondrial matrix while F0 subunit is hydrophobic and remain in the inner membrane (it contains the proton channel).
424
What are the main characteristics of circulation in birds and mammals?
They have four chambers with completely separated pulmonary and systemic circuits. -Oxygenated and deoxygenated blood cannot mix. -Respiratory gas exchange is maximised. -The two circuits can operate at different pressures.
425
What are Hydrophilic hormones and how are they divided?
Hormones that are highly soluble in water and have low lipid solubility. They are peptides or amines.
426
What are the two main characteristics of positive feedback?
1) Time limitation 2) Intensification of stress.
427
What are the 4 different kind of carbohydrates according to the number of monomers?
1-Monosaccharides 2-Disaccharides 3-Oligosaccharides 4-Polysaccharides
428
Describe fimbriae and pili in prokaryotic cells:
Hairlike structure used for adherence and movement.
429
Describe simple diffusion:
Molecules within a particular species tend to evenly distributed over time.
430
What are the two ways of dealing with osmotic changes?
1) Osmoregulation: maintain the body isosmotic state by regulating the ECF to protect the ICF 2) Osmoconformation: tolerate changes in osmotic movement.
431
Describe glycogen:
Is a polysaccharide of glucose and the form of energy storage in animals. Is water-insoluble and resist osmotic pressure.
432
What is the electrochemical gradient?
Is the net effect of simultanoeus chemical and electrical gradient on the movement of ions across the membrane.
433
What is the reaction from which macromolecules are usually formed?
Condensation reactions assemble polymers from monomers forming a covalent bond and releasing water. (energy is added to the system)
434
Describe neurotransmitter
Released by neurons and are short distances chemical messenger.
435
Describe carrier mediated transports:
A carrier protein spans the thickness of the plasma membrane and undergoes specific conformational change that allow the transport of substances.
436
Describe the smooth endoplasmic reticulum:
It lacks ribosomes and is more tubular than the RER. It's responsable for the chemical modification of small molecules taken by the cell and the site of glycogen degradation and synthesis in animal cells.
437
What is diffusion coefficient:
Diffusion is the rate at which molecules encounter with one another.
438
Describe the chemiosmotic gradient
The concentration of protons is higher in the intermembrane region thus protons would flow back into the matrix but the lipid bilayer is impermeable to them. pH is lower in the intermembrane region.
439
Describe symport:
Solute and Na+ move in the same direction.
440
What is the reaction from which macromolecules are usually broken down?
Hydrolisis breaks down polymers to their simple units by adding water to the system (energy is released)
441
Describe neuroendocrine reflexes:
Include neural as well as endocrine components and it produce a sudden increase in hormone secretion in resposne to specific stimulus.
442
Describe complementary base pairing:
Thymine will always pairs with Adenine, forming two hydrogen bonds. Guanine will always pair with Cytosine forming three hydrogen bonds.
443
What is the mitochondrial matrix?
Is the space enclosed by the inner membrane of the mitochondrion.
444
What are the two forms of carrier-mediated transport:
1) Facilitated diffusion. 2) Active transport.
445
How is energy provided in cells?
It is provided through high energy electrons.
446
What are the properties of the action of the nervous system?
It coordinates rapid and precise responses and is important in mediating the body's interactions with the external environment.
447
Describe the endoplasmic reticulum:
Is the totality of all membrane branching throughout the cytoplasm, forming tubes and flattened sacs. Is differentiated into rough endoplasmi reticulum and smooth endoplasmic reticulum.
448
Describe the -1 law of thermodynamics:
Heat travels from hot to cold
449
Describe saturation of carrier mediated transports:
A limited number of carrier binding sites are availabel within a particular plasma membrane for a specific substance. This limit is know as the transport maximum.
450
Describe closed system:
Closed system exchange only energy with the sorroundings.
451
What are the two factors that affect the action potential?
-Direction of the movement of ions (influx or efflux) -Charge of those ions.
452
What are polysaccharides?
Polymers of hundreds or thousands of monosaccharides.
453
What are the three methods of asexual reproduction?
1) Budding 2) Regeneration 3) Parthenogenesis
454
What are the main characteristics of circulation in amphibians?
Amphibians have 3 chambers. -Pulmonary and systemic circulations are partially separated. -They have two atria, the left receives the oxygenated blood whereas the right receives the deoxygenated blood. -They can take oxygen from blood vessels in their skin.
455
Describe the function of nexin:
It can cross-link the doublets and prevent from moving and sliding, in this case the cilium bends.
456
Describe integral membrane proteins:
They are noncovalently embedded in the phospholipid bilayer by their hydrophobic regions.
457
What is the function of the cardiovascular system?
To transport things around the boyd
458
What generates the downstroke of the action potential?
The downstroke is generated by a displacemente in time of the opening of K+ channels that cause a delay in K+ efflux.
459
What is the general formula of carbohydrates?
Cx(H2O)y. The carbon atoms are bonded with both hydrogen atoms and hydroxyl groups.
460
What does negative-feedback control do?
It maintains the concentration of a hormone at a given level (called set point). It is turned off when the concentration of the hormone is re-estabilished.
461
Describe primary active transport:
Energy is directly required to move a substance against its concentrationg gradient.
462
Describe active driving forces:
Require cell to expend energy in the form of ATP to transport substances across the membrane.
463
Describe the three key steps of Oogenesis:
1) Oogonia proliferate through mitosis and the resulting primary oocyte immediately enter prophase 1 2) The first meiotic division produces a polar body and a secondary oocyte. 3) The second meiotic division forms an haploid ootid which then idfferentiate into a mature ovum and a second polar body.
464
Describe active transport
It requires energy to transfer molecules against the concentration gradient.
465
Describe antiport:
Solute and Na+ move in opposite directions.
466
What is the equilibrium potential?
Is the potential at which there is no net movement of ions across the plasma membrane.
467
What are the three main components of the plasma membrane that form the fluid mosaic models?
-Phospholipid bilayer -Proteins -Carbohydrates
468
Describe gap junctions:
Comunicating junctrions that allow the movement of charge molecules between two adjacent cells.
469
What does selectively permeable means?
That the plasma membrane permits some particles to pass through while excluding other particles.
470
What are gastrovascular cavities?
Highly branched central cavities that bring the external environment into the organism.
471
What are disaccharides?
Two simple sugars linked by covalent bonds (Glycosidic linkages).
472
Describe starch:
Is a polysaccharide of glucose linked by α-glycosidic linkages. It's the principal energy storage in plants.
473
Describe gap junctions:
Comunicating junctrions that allow the movement of charge molecules between two adjacent cells.
474
What are the two ways by which energy can be transfered from the system to the sorrounding?
1)Heat 2) Work
475
Describe Glycerophospholipids:
They have a backbone of glycerol just like triglycerides but they differ because one of the three fatty acids is replaced with a phosphodiester group.
476
Describe the overall function of lysosome and vacuole:
Cellular digestive systems in which large molecules are hydrolyzed into usable monomers.
477
Describe exocytosis:
Membrane enclosed vesicles formed within the cells fuse with the plasma membrane releasing its content to the exterior.
478
How does ADH act?
It binds to vasopressine receptor to induce the migration of aquaporins to the apical membrane and this allowe water to flow back from the filtratea and the urine is thus more concentrated.
479
Describe the functions of the nervous and the endocrine system:
-Nervous system: coordintes rapid, precise responses and mediate the body interaction with the external environment. -Endocrine system: controls processes that require duration rather than speed, especially to maintain homeostasis.
480
Estrogen at low levels...
Inhibits
481
What are the two forms of vesicular transport?
1) Exocytosis 2) Endocytosis
482
What are the two main components of prokaryotic cytoplasm?
1) Water that contains ions, small molecules and solube macromolecules. 2) Ribosomes.
483
Describe relative refractory period:
A strong stimulus can fire a second action potential.
484
What are disaccharides?
Two simple sugars linked by covalent bonds (Glycosidic linkages).
485
What are the three things that must happen at the molecular level in order for a reaction to occur?
1-Molecules must collide 2-Molecules must collide with the right orientation 3-Molecules colliding with the right orientation must have enough energy to overcome the activation energy barrier
486
What are the factors that alter the affinity for O2?
1) Hemoglobin chemical composition 2) pH 3) presence of 2,3 -biphosphoglyceric acid (that lowes the affinity for O2).
487
Describe peripheral membrane proteins:
Polar molecules that don't penetrate the membrane, instead they adhere tightly to the cytoplasmic or extracellular surface.
488
What are the three foundamental steps of sexual reproduction?
1) Gametogenesis 2) Spawning or mating 3) Fertilisation
489
Describe diffusion down an electrical gradient:
A difference in charge across two adjacent areas promotes the movements of ions toward the area with opposite charge.
490
What are passive driving forces?
Forces that do not require cells to spend energy to produce movement.
491
What is a nucleotide?
A unit of the polynucleotide composed of a nucleoside (a sugar and an amino base) and a phosphate group.
492
What is redox potential?
Reduction potential is a mesure of how readily a compound donates and electron compare do Hydrogen.
493
Describe facilitated diffusion:
It doesn't require energy and use a carrier to facilitate the transfer of a substance down its concentration gradient.
494
Why are CAMs important?
Because they hepl regulating cell shape, growth and differentiation and allow the cell to adapt to its immediate sorroundings.
495
What are channels?
Water filed pathways that serve as conduits that allow water molecules and ions to flow passively through the lipid bilayer.
496
State the seven functions of membrane proteins:
1) Ligand Binding Receptor 2) Cell Adhesion Molecules (CAM) 3) Channels 4) Carriers and pumps 5) Membrane-bound enzymes 6) They participate to intracellular signaling 7) Docking marker acceptor
497
What are oligosaccharides?
Polymers of 3 to 20 simple sugars.
498
What are the two main kind of fertilization?
1) External fertilization 2) Internal fertilization
499
What happens to phospholipids in an aqueous environment?
They tend to form a lipid bilayer with hydrophilic heads pointing outward. The water is excluded from the hydrophilic core.
500
Describe excitation (without indicating Jacopo thx):
At excitatory synapses channels have a reverse potential that is more positive than threshold, thus an AP is fired.
501
What are the two types of driving forces?
Active and passive driving forces.
502
State the properties of the lipid bilayer:
1- Is fluid because phospholipids are not held togeterh by covalent bonds. 2- Cholesterlo contributes to both the fluidity and the stability of the membrane. 3- The phospholipids are constantly moving 4- The phospholipid bilayer is impermeable to charged molecules and water soluble molecules.
503
Describe substrate level phosphorylation
Energy for phosphorylation is obtianed from substrate of biochemical reaction and a phosphate group is directly transfered to ADP to form ATP.
504
What's a phosphodiester linkage?
The phosphate group links carbon 3' of one sugar to carbon 5' of another sugar).
505
If ΔS is positive...
The reaction is spontaneous and exothermic.
506
What is the two possible structural configuration of monosaccharides?
-Straight chain -Ring (Cyclic)
507
What are the properties of the plasma membrane?
1- Forms the outer boundary of the cell 2- It's selectively permeable 3- Controls the entrance of nutrients and exit of waste products. 4- Mantain the difference in concentration between the inside and the outside of the cell. 5- Particippiate in the joining of cells to form tissues and organs. 6- Allow cells to interact in different ways with the same extracellular fluid.
508
Describe negative-feedback control:
Maintain the plasma concentration of hormone at a given level.
509
What are the two different types of depolarizing stimulus?
-Subthreshold depolarizing stimulus (not sufficiently large to fire an AP). -Threshold depolarizing stimulus.
510
What are the two functions of membrane carbohydrates?
1) They act as self identity markers that enable cells to identify and interact with one another. 2) They have a role in tissue growth and prevent cells to trespass across the boundary of neighbouring tissues.
511
What are the four steps involved in neurotransmission?
1) An action potential reaches and depolarizes the axon terminal. 2) The depolarization opens voltage gated Ca2+ channels and it enters the cell. 3) Calcium ions cause the exocytosis of synaptic vesicles content. 4) Neurotransmitter diffuse across the synaptic cleft and binds to the receptor.
512
What are the two sub-disciplines of thermodynamics?
Classical thermodynamics and statistical thermodynamics.
513
What does the solubility of hormones determine?
1) How the hormones is synthesized, stored and secreted by the endocrine system. 2) How the hormone is transported by the blood. 3) How the hormone exert its effect at a target cell.
514
What are the two ways to phosphorylate ATP?
Substrate level phosphorylation and oxidative phosphorylation
515
What are the advantages of a circulatory system?
-Fluid moves more rapidly and the diameter of blood vessels can be adjusted to control the flow to selected tissues. -Specialized cells and large molecules that aid transporting hormones and nutrients can be kept in the vessles.
516
Describe phospholipids:
They have a phosphate group that links a substituent group to a glycerlo unit (this form the hydrophilic and polar head) and two fatty acids chains (that form the hydrophobic and nonpolar tails).
517
Describe Ligand Binding Receptor
Sites that recognize and bind with specific extracellular chemical messengers.
518
What effect has 2,4-Dinitrophenol on the production of ATP?
It forms a proton channel in the inner membrane of the mitochondrion so that the proton gradient cannot be formed and energy is release as heat instead of ATP.
519
What's a phosphodiester linkage?
The phosphate group links carbon 3' of one sugar to carbon 5' of another sugar).
520
What are high energy electrons?
Electrons with negative redox potential that tend to flow to positive redox potential.
521
What is DNA?
Deoxyribonucleic acid, a polynucleotide that encodes hereditary information and passes it from generation to generation.
522
What happens if the membrane is permeable to a molecule
Molecules move down their concentration gradient (from high concentration to low concentration).
523
Describe chemoautotrophs
The energy source of chemoautotrophs are chemical bonds and the carbon source is CO2
524
Describe classical thermodynamics:
Classical thermodynamics deals with bulks propertiens and consider the macroscopic properties of matter.
525
Describe the roles of intermediate filaments:
1) They anchro the cell structure in place. 2) They help resisting tension.
526
Describe tight junctions:
Adjacent cells bind firmly with one another at points of direct contact to seal of the passageway betweent cells.
527
What's induced fit?
A change in the shape of either the enzyme and the substrate (or both) that lower the activation energy.
528
Circulatory systems can be:
-Open -Closed
529
What are the two components of the Golgi apparatus
1) Cisternae 2) Small-membrane enclosed veiscles.
530
How is the ester linkage formed?
Through a condensation reaction between the carboxyl group of the fatty acid and a hydroxyl group of the glycerol.
531
What are the two characteristics of oligosaccharides?
They may have additional functional groups which give them special properties and they may be covalently bonded to proteins and lipids on the cell surface acting as recognition signals.
532
Describe the rough endoplasmic reticulum:
Is called rough because of the many ribosomes attached to it. It receivse newly synhtesized proteins, segregating them away from the cytoplasm and transport them in other locations.
533
What are triglycerides?
Compound composed of the three carbon alcohol glycerol linked to three fatty acids via ester linkages.
534
What are the four different types of extracellular communication:
1) Paracrines 2) Neurotransmitter 3) Hormones. 4) Neurohormones.
535
What is a glycosidic link?
A glycosidic link is the result of a condensation reaction between a hydroxyl group on one sugar and a hydroxyl group on another sugar.
536
What are the three main components of the plasma membrane that form the fluid mosaic models?
-Phospholipid bilayer -Proteins -Carbohydrates
537
Describe isotonic condition:
The osmolarity of the inside is equal to the osmolarity of the outside so there's no net movement of water and no change in volume of the cell.
538
What are the two components of the extracellular fluid in closed circulatory system?
1) Blood plasma: fluid in the circulatory fluid 2) Interstitial fluid: Fluid around the cells
539
Describe cell adhesion molecules (CAM)
They can either protrude from the outer membrane surface and form hooks and loops or span the plasma membrane where they serve as structural link between the outer membrane surface and its extracellular sorroundings.
540
What does the sourge in LH cause?
It triggers ovulation and stimulates the follicle cells to develop into the corpus lutenum and to secrete progesterone and estrogen.
541
What happens to phospholipids in acqueous environment?
They thend to form a lipid bilayer.
542
Describe the cisternae also stating the three regions that compose them:
Flattened membranous sacs called cisternae: 1) Cis region lies nearest to the nucles or a patch of RER. 2) Trans region lies nearest to the plasma membrane. 3) Medial region lies in between.
543
What's heat?
Heat is energy dispersed in a random motion
544
What's Activation Energy?
The minimum energy a reactant molecule has to posses to initiate the bond cleavage and formation process.
545
How is genetic information encoded in the DNA?
Is encoded as the sequence of bases.
546
Describe the molecular structure of enzymes:
They are usually globular proteins consisting of one long chain of amino acids folded into a spherical shape determined by non covalent intermolecular forces.
547
What are the four factors that affect the plasma concentration of a specific hormone?
1) Rate of secretion of that hormone.
2) Rate of conversion or metabolic activation.
3) Affnity with plasma proteins (only for lipohilic)
4) Rate of removal from the blood.
548
Cofactors usually come from...
minerals and vitamins in our diet
549
Describe cellulose:
Is a polysaccharide of glucose with β-glycosidic linkages, thus is more stable and an excellent structural component. Is the major component of plant cell wall.
550
What is the reaction from which macromolecules are usually formed?
Condensation reactions assemble polymers from monomers forming a covalent bond and releasing water. (energy is added to the system)
551
What's a system?
A system is anything contained within a boundary.
552
What is the nucleoid in prokaryotic cells?
The region where DNA is located.
553
Describe steroids:
Tetracyclic compounds made up of a series of alkyl rings linked by shared carbon.
554
What happen at Vmax?
The enzyme is working at full capacity and it's saturated (any active site has a substrate molecule bound to it).
