Chapter 6

Question 1

Oxidoreductases

Answer 1

oxidation-reduction reactions

Question 2

Transferases

Answer 2

transfer functional groups from one molecule to another

Question 3

Hydrolases

Answer 3

hydrolysis reactions - using water to break one molecule into two

Question 4

Lyases

Answer 4

remove a group from one molecule and rearrange the electrons

Question 5

Isomerases

Answer 5

convert two molecules with the same formula into different structures

Question 6

Ligases

Answer 6

join two molecules together

Question 7

What is the catalytic cycle of an enzyme?

Answer 7

1. substrate binding
2. substrate activation
3. catalytic event
4. product release

Question 8

Name the 6 classes for enzyme nomenclature

Answer 8

oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases

Question 9

How does a catalyst increase the rate of a reaction?

Answer 9

by lowering the activation energy requirement

Question 10

Activation Energy

Answer 10

how much energy required to get to a state to turn substrate into product

Question 11

Active Site

Answer 11

where substrate binds to enzyme

Question 12

Prostetic groups

Answer 12

small organic groups or metal ions on an enzyme that function as electron acceptors

Question 13

Lock and Key Model

Answer 13

early model that explained enzyme specificity but not catalytic event

Question 14

Induced Fit Model

Answer 14

when enzyme binds to substrate, both change shape

Question 15

What is initial binding of substrate and enzyme caused by

Answer 15

RANDOM COLLISION!

Question 16

Km

Answer 16

michaelis constant

specific substrate concentration at which the reaction proceeds at half it’s max speed

Question 17

Vmax

Answer 17

upper limit of reaction rate

only way to speed up is to get more enzymes

Question 18

Enzyme Regulation

Answer 18

mechanisms that adjust the rate of enzyme catalyzed reactions

Question 19

5 types of enzyme regulation

Answer 19

alter temp or pH, 
allosteric regulation,
 covalent modification, 
competitive inhibition, 
and substrate level regulation

Question 20

Competitive Inhibition

Answer 20

molecule binds to the active site so that substrates can’t bind

Question 21

what are substrate analogs

Answer 21

pretend substrates used in competitive inhibition

Question 22

Allosteric Regulation

Answer 22

binding of regulatory molecules at allosteric site that can turn molecule on or off

Question 23

Feedback Inhibition

Answer 23

when cell has made enough of the product, the product binds to the allosteric site and inhibits the enzyme that made it

Question 24

Covalent Modification

Answer 24

enzyme activity affected by addition or removal of chemical groups via covalent bonding

Question 25

Types of covalent modification

Answer 25

proteolytic cleavage and phosphorylation/dephosphorylation

Question 26

proteolytic cleavage

Answer 26

one-time irreversible removal of a portion of the polypeptide chain

Question 27

Ribozymes

Answer 27

RNA molecules that act as catalysts