PPT Notes: Chapter 2 Flashcards

Question

Molecules and compounds

Answer 1

most atoms combine chemically by bonding with other atoms to form molecules and compounds

Answer 2

any two or more atoms bonded together * e.g. H₂ or C₆H₁₂O₆

Answer 3

two or more different kinds of atoms bonded together * e.g. C₆H₁₂O₆ * can be chemically bonded * all are homogeneous

Answer 4

* Most matter exists as mixtures * two or more components physically intermixed * no chemical bonding between components * can be separated physically by straining or filtering * heterogeneous (varied makeup) or homogeneous (pure makeup)

Answer 5

3 types * solutions * colloids * suspensions

Answer 6

* homogeneous mixtures * usually transparent (e.g. atmospheric air or seawater) * solvent * present in greatest amount, usually a liquid * solute * present in smaller amounts

Answer 7

Expressed as: * percent, or parts per 100 * Milligrams per deciliter (mg/dl) * Molarity, or moles per liter (M)

Answer 8

* 1 mole = the atomic weight of an element or molecular weight (sum of atomic weights) of a compound in grams * 1 mole of anysubstance contains 6.02 x 10²³ molecules (Avogadro's number)

Answer 9

6.02 x 10²³

Answer 10

* eg Mayo * heterogeneous translucent mixtures eg cytosol * large solute molecules that do not settle out * undergo sol-gel transformations

Answer 11

* heterogeneous mixtures eg blood * large visible solutes tend to settle out

Answer 12

seven electron shells (energy levels) around nucleus.

Answer 13

Except for the first shell which is full with two electrons, (duet rule) atoms interact in a manner to have eight electrons in their outermost energy level (valence shell)

Answer 14

* stable and unreactive * outermost energy level fully occupied or contains eight electrons * Noble Gases

Answer 15

* outermost energy level not fully occupied by electrons * tend to gain, lose or share electrons (form bonds) with other atoms to achieve stability

Answer 16

* Ionic * Covalent * Hydrogen

Answer 17

* Ions are formed by transfer of valence shell electrons between atoms * anions - (– charge) have gained one or more electrons * cations - (+ charge) have lost one or more electrons * Attraction of opposite charges results in an ionic bond

Answer 18

* Ionic compounds form crystals instead of individual molecules * NaCl (sodium chloride)

Answer 19

* Formed by sharing of two or more valence shell electrons * Allows each atom to fill its valence shell at least part of the time * Sharing of electrons may be equal or unequal * sharing produces electrically balanced nonpolar molecules eg CO₂ * unequal sharing by atoms with different electron-attracting abilities produces polar molecules eg H20 * Atoms with six or seven valence shell electrons are electronegative, e.g., oxygen * Atoms with one or two valence shell electrons are electropositive, e.g., sodium

Answer 20

* Attractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule * Common between dipoles such as water * Also act as intramolecular bonds, holding a large molecule in a three-dimensional shape

Answer 21

* Occur when chemical bonds are formed, rearranged, or broken * Represented as chemical equations * Chemical equations contain: * Molecular formula for each reactant yields product * Relative amounts of reactants and products, which should balance eg * H+H ---\>H₂ (hydrogen gas) * 4H+C ---\> CH₄ (methane)

Answer 22

* Synthesis (combination) reactions * Decomposition reactions * Exchange reactions

Answer 23

A + B ---\> AB * Always involve bond formation * Anabolic (building)

Answer 24

AB ---\> A+B * Reverse synthesis reactions * Involve breaking of bonds * Catabolic

Answer 25

AB+C ---\> AC+B * also called displacement reactions * bonds are both made and broken

Answer 26

* Decomposition reactions: Reactions in which fuel is broken down for energy * Also called exchange reactions because electrons are exchanged or shared differently * electron donors lose electrons and are oxidized * electron acceptors receive electrons and become reduced

Answer 27

* All chemical reactions are either endergonic or exergonic * Exergonic reactions— release energy * catabolic reactions * Endergonic reactions—products contains more potential energy than did reactants * anabolic reactions * All chemical reactions are theoretically reversible * A + B ---\> AB * AB ---\> A + B * Chemical equilibrium occurs if neither a forward nor reverse reaction is dominant * Many biological reactions are essentially irreversible due to: * Energy requirements * Removal of products

Answer 28

Influenced by: * increased temperature = increased rate * decreased particle size = increased rate * increased concentration of reactant = increased rate Catalysts * increase rate without being chemically changed * biological catalysts are known as enzymes

Answer 29

Inorganic * water, salts, and many acids and bases * do not contain carbon \*carbon dioxide and monoxide are both inorganic Organic * carbohydrates, fats, proteins and nucleic acids * contain carbon, usually large and are covalently bonded

Answer 30

* 60-80% of the volume of living cells * most important inorganic compound in living organisms because of its properties * high heat capacity * absorbs and releases heat with little temperature change * prevents sudden changes in temperature * high heat of vaporization * evaporation requires large amounts of heat * useful cooling mechanism * polar solvent properties * dissolves and dissociates ionic substances * forms hydration layers around large charged molecules e.g. proteins (colloid formation) * Body's major transport medium * reactivity * a necessary part of hydrolysis and dehydration synthesis reactions *

Answer 31

* ionic compounds that dissociate in water * contain cations other than H+ and anions other than OH- * Ions (electrolytes) conduct electrical currents in solution * Ions play specialized roles in body functions (eg sodium, potassium, calcium and iron)

Answer 32

both are electrolytes * acids are proton (hydrogen ion) donors (release H+ in solution) * HCl ---\> H⁺ + Cl^- * bases are proton acceptors (take up H+ from solution) * NaOH ---\> Na⁺ + OH^- * OH- accepts an available proton (H+) * OH^- + H⁺ ---\> H₂O * \*Hydrogen\* Bicarbonate ion (HCO₃-) and ammonia (NH₃) are important bases in the body

Answer 33

H+ * H+ increases, acidity increases

Answer 34

bases (eg OH-) * as H+ decreases (or as OH- increases), alkalinity increases

Answer 35

the negative logarithm of H+ in moles per liter

Answer 36

* pure water is pH neutral (contains equal numbers of H+ and OH-) * pH of pure water = pH 7: H+ = 10^-7 M * all neutral solutions are pH 7

Answer 37

* increased H+ , decreased pH (inversely proportionate) * acidic pH: 0-6.99 * pH scale scale is logarithmic: a pH 5 solution has 10 times more H+ than a pH 6 solution

Answer 38

* decreased H+, increased pH (inversely proportionate) * alkaline (basic) pH: 7.01 - 14

Answer 39

function and may damage living tissue * slight change in pH can be fatal * pH is regulated by kidneys, lungs and buffers

Answer 40

* mixture of compounds that resist pH changes * convert strong (completely dissociated) acids or bases into weak (slightly dissociated) ones * carbonic acid-bicarbonate system

Answer 41

* contain carbon (except CO2 and CO which are inorganic) * unique to living systems * include carbohydrates, lipids, proteins and nucleic acids * many are polymers - chains of similar units (monomers or building blocks) * synthesized by dehydration synthesis, which is the removal of water * broken down by hydrolysis reactions

Answer 42

* sugars and starches * contain C, H and O (CH₂O)_n * Three classes * monosaccharides * disaccharides * polysaccharides * functions * major source of cellular fuel (eg glucose) * structural molecules (eg ribose sugar in RNA)

Answer 43

* simple sugars containing three to seven C atoms * (CH₂O)_n

Answer 44

* double sugars * too large to pass through cell membranes

Answer 45

* polymers of simple sugars eg starch and glycogen * not very soluble

Answer 46

* Contain C, H, O (less in carbohydrates) and sometimes P * Insoluble in water

Answer 47

PENTS * neutral fats or triglycerides * phospholipids * steroids * eicosanoids

Answer 48

* neutral fats - solid fats and liquid oils * found in butter, meats, etc * composed of three fatty acids bonded to a glycerol molecule * main functions * energy storage * insulation * protection

Answer 49

* single bonds between C atoms; maximum number of H * solid animal fats e.g. butter

Answer 50

* one or more double bonds between C atoms * reduced number of H atoms * plant oils, e.g. olive oil

Answer 51

* Modified triglycerides: * glycerol + two fatty acids and a phosphorus (P)-containing group * head and tail regions have different properties * important in cell membrane structure

Answer 52

interlocking four-ring structure Examples: * cholesterol * vitamin D * steroid hormones * bile salts

Answer 53

come in two broad groups: * leukotrienes * prostanoids both of which are involved in signaling between cells

Answer 54

other fat-soluble vitamins * Vitamins A, E, K Lipoproteins * transport fats in the blood

Answer 55

polymers of amino acids (20 types) * joined by peptide bonds Contain C, H, O, N and sometimes S and P \*NCHOPS

Answer 56

Fibrous (structural) proteins * Strandlike, water insoluble, and stable Examples: * keratin * Elastin * Collagen * certain contractile fibers

Answer 57

Globular (functional) proteins * Compact, spherical, water-soluble and sensitive to environmental changes * Specific functional regions (active sites) Examples: HAME * antibodies * hormones * molecular chaperones * enzymes

Answer 58

* Shape change and disruption of active sites due to environmental changes (e.g., decreased pH or increased temperature) * Reversible in most cases, if normal conditions are restored * Irreversible if extreme changes damage the structure beyond repair (e.g., cooking an egg)

Answer 59

serve as the rescue team * Ensure quick and accurate folding and association of proteins * Assist translocation of proteins and ions across membranes * Promote breakdown of damaged or denatured proteins * Help trigger the immune response * Produced in response to stressful stimuli, e.g., O2 deprivation

Answer 60

Biological catalysts * lowers the activation energy, increases the speed of a reaction (millions of reactions per minute) * often named for the reaction they catalyze; usually end in ase (e.g. hydrolases, oxidases) * examples include: * hydrolases that add water * Oxidases that add oxygen * Not all end in -ase (e.g. pepsin, gastrin, etc)

Answer 61

* Binding of enzyme’s active site to the substrate(s). * Formation of the enzyme substrate complex. * Release of the products from the enzyme.

Answer 62

DNA and RNA * Largest molecules in the body * Contain C, O, H, N, and P * Building block = nucleotide, composed of N-containing base, a pentose sugar, and a phosphate group

Answer 63

* Four bases: * adenine (A), guanine (G), cytosine (C), and thymine (T) * double stranded helical molecule in the cell nucleus * Provides instructions for protein synthesis during normal cell functioning. * Replicates before cell division, ensuring genetic continuity during cellular reproduction.

Answer 64

* Four bases: * adenine (A), guanine (G), cytosine (C), and uracil (U) * single stranded molecule mostly active outside the nucleus * Three varieties of RNA carry out the DNA orders for protein synthesis [there are others] * messenger RNA [mRNA] * transfer RNA [tRNA] * ribosomal RNA [rRNA]

Answer 65

* Adenine-containing RNA nucleotide with two additional phosphate groups * Adenine-Phosphate-Phosphate-Phosphate * Has the highest potential energy * Adenine-Phosphate-Phosphate * ADP : adenosine diphosphate * Adenine-Phosphate * AMP : adenosine monophosphate

Answer 66

Phosphorylation: * Terminal phosphates are enzymatically transferred to and energize other molecules * Breaking the bonds between phosphates releases the potential enregy. * Such “primed” molecules perform cellular work (life processes) using the phosphate bond energy