Molecules, Energy, and Biosynthesis

Question 1

diverse group of water-insoluble biological molecules

Answer 1

Lipids

Question 2

energy stores

Answer 2

Fats

Question 3

major components of membrane.

Answer 3

Phospholipids and Sterols

Question 4

polyhydroxy aldehydes and ketones with the general formula of (CH2O)n.

Answer 4

Carbohydrates

Question 5

most complex and most abundant organic molecules containing at least one carboxyl group and one amino group.

Answer 5

Proteins

Question 6

DNA and RNA

Answer 6

Nucleic Acid

Question 7

carries coded information, arranged into genes, that is passed from each cell to its daughter cells and from one generation to the next

Answer 7

DNA

Question 8

instrumental in translating the coded message of DNA into sequences of amino acids during synthesis of protein molecules

Answer 8

RNA

Question 9

Proteins – most complex and most abundant organic molecules containing at least one ______ and ____.

Answer 9

carboxyl group
one amino group

Question 10

The process of increasing the rate of reaction with the use of a catalyst.

Answer 10

Catalysis

Question 11

any substance that increases rate of reaction upon addition to a certain reaction .

Answer 11

Catalyst

Question 12

catalyst of biochemical reactions (biological catalysts)

Answer 12

Enzymes

Question 13

neither used up in the reaction nor do they appear as reaction products

Answer 13

Enzymes

Question 14

are proteins of very specific amino acid composition and sequence

Answer 14

Enzymes

Question 15

catalyze all the synthetic and metabolic reactions of the cell

Answer 15

Enzymes

Question 16

The kinetic energy required to bring the reactants into position to interact.

Answer 16

Activation Energy

Question 17

measured as the number of calories required to bring all the molecules in a mole of reactant at a given temperature to a reactive (or activated) state.

Answer 17

Activation Energy

Question 18

How do enzymes hasten the reaction?

Answer 18

enzyme (E) binds with a substrate (S) to form an activated enzyme-substrate complex (ES*).

Question 19

each enzyme is specific for a certain substrate (reactant molecule)

Answer 19

Enzyme Specificity

Question 20

hydrolyses any peptide bond in which the carbonyl group belongs to a phenylalanine, tyrosine, or tryptophan residue.

Answer 20

Chymotrypsin

Question 21

(proteolytic enzyme present in the intestine - protein hydrolysing)

Answer 21

Chymotrypsin

Question 22

highly specific nature of most enzymes arises from the close and complementary fit between enzymes and substrate in a special portion of the enzyme surface

Answer 22

Active Site

Question 23

where the substrate can fit like a lock-and-key mechanism

Answer 23

Active Site

Question 24

catalytic potency of an enzyme

Answer 24

Enzyme Activity

Question 25

number of reactions catalyzed per second by the enzyme

Answer 25

turnover number

Question 26

How enzymes accelerate reactions

Answer 26

-Holds substrate in close proximity to one another in order to enhance the probability of a reaction -form an unstable intermediate that readily undergoes second reaction -presence of proton donors and acceptors in the active site of the enzyme

Question 27

Factors affecting enzyme activity

Answer 27

Temperature and Reaction Rates

Question 28

as ____ increases, reaction rate initially increases (increased kinetic energy of the substrate molecule)

Answer 28

temperature

Question 29

as temperature increases further, reaction rate decreases____ (onset of denaturation)

Answer 29

decreases

Question 30

reaction rate is maximal at the _____.

Answer 30

optimal temperature

Question 31

drop in pH exposes more _____ on an enzyme for interaction with _____ on a substrate molecule

Answer 31

positive sites negative groups

Question 32

rise in pH facilitates the binding of ____ on a substrate to ____ on the enzymes.

Answer 32

positive groups negative sites

Question 33

small organic molecules that act as cofactors

Answer 33

coenzymes

Question 34

enzyme minus its cofactor; cannot function without its cofactor/coenzyme

Answer 34

apoenzyme

Question 35

Classified according to the types of reaction they catalyze

Answer 35

-Oxidoreductase -Transferase -Hydrolase -Lyase -Isomerase -Ligase

Question 36

Oxidation-reduction

Answer 36

Oxidoreductase

Question 37

Group Transfer

Answer 37

Transferases

Question 38

Hydrolysis reaction

Answer 38

Hydrolases

Question 39

Addition or removal of groups to form double bonds

Answer 39

Lyases

Question 40

Isomerazation

Answer 40

Isomerases

Question 41

Ligation of two substrates at the expense of ATP hydrolysis

Answer 41

Ligases

Question 42

used in the living cell as a means of controlling enzymatic reactions

Answer 42

Enzyme Inhibition

Question 43

enzymes can be ___ (toxins) or ____ inhibited

Answer 43

irreversibly reversibly

Question 44

Two types of Inhibition

Answer 44

Competitive and noncompetitive

Question 45

caused by molecules that react directly with the active site of the enzyme

Answer 45

Competitive Inhibition

Question 46

can be reversed by an increase in substrate concentration

Answer 46

Competitive Inhibition

Question 47

most competitive inhibitors are ____.

Answer 47

substrate analogs

Question 48

caused by molecules that bind to a region(s) of the enzyme outside the active site

Answer 48

Noncompetitive Inhibition

Question 49

reversed by dilution or removal of the inhibitor

Answer 49

Noncompetitive inhibition

Question 50

chemical structure of noncompetitiveinhibitors typically differs from that of the substrate.

Answer 50

Noncompetitive Inhibition

Question 51

Regulation of Metabolic Reactions

Answer 51

1.Control of Enzyme Synthesis 2. Control of enzyme activity 3.End product inhibition

Question 52

Certain conditions that reduce protein synthesis generally

Answer 52

Control of enzyme synthesis

Question 53

regulated at the molecular level by modulation of the rate of transcription of the gene encoding it (DNA is packaging; rate at which RNA is translated into proteins)

Answer 53

Control of Enzyme Synthesis

Question 54

regulated by modulator molecules (interact with a part of the enzyme molecule –allosteric site - distinct from the active site)

Answer 54

Control of Enzyme Activity

Question 55

alters the tertiary structure of the enzyme thus changing the conformation of the active site

Answer 55

Allosteric Site

Question 56

the affinity of the enzyme for its substrate decreases or increases

Answer 56

Control of Enzyme Activity

Question 57

first enzyme of the sequence that acts as the regulatory enzyme

Answer 57

End-product inhibition

Question 58

end product of the pathway feeds back to inhibit the activity of this first enzyme

Answer 58

End-feedback product Inhibition

Question 59

interaction of the end product occurs in the allosteric site, making the end product an _____.

Answer 59

allosteric inhibitor

Question 60

limits the rate of accumulation of the end product by slowing the entire sequence from the beginning

Answer 60

End-product Inhibition

Question 61

several cat-ion cofactors act as allosteric activators for some enzymes

Answer 61

Enzyme Activation

Question 62

Two kinds of energy yielding metabolic pathways in animal tissues

Answer 62

Aerobic Metabolism Anaerobic Metabolism

Question 63

food molecules are completely oxidized to carbon dioxide and water by molecular oxygen; energy yield is far greater

Answer 63

aerobic Metabolism

Question 64

food molecules are oxidized incompletely to lactic acid (lactate); absence of oxygen

Answer 64

Anaerobic Metabolism

Question 65

Cofactor + Apoenzyme

Answer 65

Holoenzyme