chapter 21 - protein and enzymes

Question 1

what is the primary structure of a protein?

Answer 1

sequence of amino acids in a protein chain

Question 2

what does the secondary structure of a protein contain?

Answer 2

alpha-helix
beta-sheet
hydrogen bonds connecting the backbone segments

Question 3

what the tertiary structure of a protein?

Answer 3

regions of secondary structure + overall bending of the protein chain

Question 4

what is the quaternary structure of a protein?

Answer 4

overall whole structure of protein, composed of more than one polypeptide chain

Question 5

which is the only amino acid that can do a disulfide bond?

Answer 5

cystine

Question 6

what is this an example of?

Answer 6

hydrophobic interactions

Question 7

what is the difference between simple vs conjugated proteins?

Answer 7

simple: composed only of amino acids
conjugated: composed of amino acids and non-amino acids

Question 8

what is the role of non-amino acids within conjugated proteins?

Answer 8

to have an ester functional group (since amino acids are not capable of having an ester)

Question 9

what type of disulfide bond?

Answer 9

intrachain disulfide bond

Question 10

what type of disulfide bond?

Answer 10

interchain disulfide bond

Question 11

what is the only amino acid that can do a disulfide bond?

Answer 11

cystine

Question 12

how many oxygen molecules can hemoglobin transport? why?

Answer 12

4
because it has 4 heme subunits which can transport 1 oxygen each

Question 13

what vitamin does collagen need? if deficient, what does this cause?

Answer 13

vitamin C
scurvy

Question 14

what structures are inhibited during denaturation? hydrolysis?

Answer 14

denaturation: 2-4 protein structures
hydrolysis: all protein structures

Question 15

what is a zwitterion?

Answer 15

a salt that contains both a positive and negative charge

Question 16

Answer 16

Question 17

what is a residue?

Answer 17

an individual amino acid within a chain

Question 18

what is specificity?

Answer 18

limit of enzyme activity to a specific substrate, or specific reaction

Question 19

what is turnover number?

Answer 19

the maximum number of substrate molecules acted upon by one enzyme per unit time

Question 20

what enzyme and what reactant cause the highest turnover number?

Answer 20

catalase - which breaks down hydrogen peroxide into water and oxygen

Question 21

what is an oxidoreductase for?

Answer 21

oxidation-reduction reactions

Question 22

what is a transferase for?

Answer 22

transfer of functional groups

Question 23

what is a hydrolase for?

Answer 23

hydrolysis reaction (turning 1 reactant into 2 proucts)

Question 24

what is a isomerase for?

Answer 24

isomerization of substrate

Question 25

what is a lyase for?

Answer 25

group elimination to form double bond or addition to a double bond

Question 26

what is a ligase for?

Answer 26

bond formation (two items turn into 1 item)

Question 27

what is a cofactor? coenzyme?

Answer 27

cofactor: nonprotein part of enzyme that does not bind to enzyme but aids in function
coenzyme: binds loosely to active site of enzyme

Question 28

what type of enzyme is being used in this reaction?

Answer 28

oxidoreductase

Question 29

what type of enzyme is being used in this reaction?

Answer 29

transferase

Question 30

what type of enzyme is being used in this reaction?

Answer 30

hydrolase (1 reactant turning into 2 products)

Question 31

what type of enzyme is being used in this reaction?

Answer 31

isomerase

Question 32

what type of enzyme is being used in this reaction?

Answer 32

lyase

Question 33

what type of enzyme is being used in this reaction?

Answer 33

ligase (turning 2 reactants in 1 product)

Question 34

induced-fit model vs lock-and-key?

Answer 34

induced: current model explaining how enzyme flexibly attaches to substrate
lock: old explanation of how active site was fixed per the substrate it binded to

Question 35

In regards to enzyme acting as catalysts, what is the proximity effect?

Answer 35

bringing substances and catalytic sites together

Question 36

In regards to enzyme acting as catalysts, what is the orientation effect?

Answer 36

hold substances at exact distance/orientation necessary

Question 37

In regards to enzyme acting as catalysts, what is the catalytic effect?

Answer 37

provide acidic, basic, etc groups required for catalysis

Question 38

In regards to enzyme acting as catalysts, what is the energy effect?

Answer 38

lower the energy barrier by inducing strain in bonds

Question 39

what is feedback control?

Answer 39

regulation of enzymes activity by amount of product further into reaction pathway

Question 40

what is allosteric control?

Answer 40

Regulator that binds to enzyme to either activate or deactivate enzyme’s active sites

Question 41

what is the difference between an uncompetitive inhibitor vs a competitive inhibitor?

Answer 41

uncompetitive: does not compete with substrate for active site/ reaction occurs less efficiently

competitive: binds reversibly to an active site preventing substrate from entering active site

Question 42

what is a Zymogen?

Answer 42

compound that becomes an active enzyme after undergoing a chemical change
must be activated by cleaving a portion of the molecule.

Question 43

what is pepsinogen an example of? what does the active enzyme become?

Answer 43

Zymogen
pepsin

Question 44

what is covalent modification?

Answer 44

phosphorylation - addition and removal of a phosphoryl group

Question 45

what is genetic control?

Answer 45

regulation of enzyme activity by control of synthesis of enzymes

Question 46

what is the difference between what makes a macromineral vs a micronutrient?

Answer 46

macro: more than 100 mg per day required
micro: minute amounts required for enzyme function

Question 47

where are water soluble vitamins found?

Answer 47

inside cells

Question 48

what is a chiral mismatch?

Answer 48

when wrong enantiomer of a substrate cannot bind to active sites of enzyme