Biochemistry

Question 1

Trypsin

Answer 1

cleaves at carboxyl end of arginine and lysine.

Question 2

Chymotrypsin

Answer 2

cleaves at carboxyl end of phenylalanine, tryptophan, and tyrosine.

Question 3

Zymogen

Answer 3

inactivated form of enzyme.

Question 4

Oxidoreductase

Answer 4

catalyze oxidation-reduction reactions.
Ex: dehydrogenase, reducatase, oxidase

Question 5

Transferases

Answer 5

catalyze the movement of a functional group from one molecule to another. Ex: kinases, aminotransferases

Question 6

Hydrolases

Answer 6

catalyze the breaking of a compound into two molecules using the addition of water.

Question 7

Lyases

Answer 7

catalyze the cleavage of a single molecule into two products.

Question 8

Isomerases

Answer 8

catalyze the rearrangement of bonds within a molecule.

Question 9

Ligases

Answer 9

catalyze addition or synthesis reactions.

Question 10

Cofactors

Answer 10

small inorganic molecules or metal ions

Question 11

Coenzymes

Answer 11

small organic groups most of which are vitamin or vitamin derivatives.

Question 12

If Hill’s coefficient is greater than 1

Answer 12

positive cooperative binding is occurring, after one ligand is bound the affinity of the enzyme for further ligand increases.

Question 13

If Hill’s coefficient is less than 1

Answer 13

negative cooperative binding is occurring, after one ligand is bound the affinity of the enzyme for further ligand decreases.

Question 14

If Hill’s coefficient is equal to 1

Answer 14

the enzyme does not experience cooperative binding.

Question 15

What are the four types of reversible inhibition?

Answer 15

competitive, non-competitive, mixed, and uncompetitive.

Question 16

Competitive Inhibition

Answer 16

involves occupancy of the active site, the Km increases, and the Vmax remains unchanged.

Question 17

Non-competitive inhibition

Answer 17

bind to an allosteric site instead of the active site, which induces a change in enzyme conformation. Km is unchanged, Vmax decreases.

Question 18

Mixed Inhibition

Answer 18

results when an enzyme can bind to either the enzyme or the enzyme-substrate complex but has different affinity for each. Km increases or decreases, Vmax decreases.

Question 19

Uncompetitive Inhibition

Answer 19

bind only to enzyme-substrate complex and essentially lock the substrate in the enzyme preventing its release. Km decreases, Vmax decreases.

Question 20

Feedback inhibition

Answer 20

refers to the product of an enzymatic pathway turning off enzymes further back in that same pathway.

Question 21

Irreversible inhibition

Answer 21

prolonged or permanent inactivation of an enzyme.

Question 22

What are examples of transient modifications to enzymes?

Answer 22

allosteric activation or inhibition

Question 23

What are examples of covalent modifications to enzymes?

Answer 23

phosphorylation and glycosylation

Question 24

What does a sigmoidal curve indicate in terms of cooperativity?

Answer 24

Positive Cooperativity and a Hill Coefficient Greater than 1.