FINAL EXAM CHAPTER 7 Kinetics and Regulation

Question 1

Define rate velocity

Answer 1

This is the measure of how much product is formed over time or how much substrate was used over time

Question 2

Define Rate constants

Answer 2

these values tell you how fast something binds or dissociates

Question 3

In the Michaelis Menten equation what does the Km, K-1, K2,K1 all mean?

Answer 3

Km-How well enzyme can bind substrate, its called Michaelis Constant
K-1-How fast it dissociates
K2-How fast the substrate is converted into product
K1-How fast it binds

Question 4

What is the relationship between Vo and Km if the Vo=1/2 Vmax

Answer 4

Km = [S]

Question 5

Why do we measure Vo?

Answer 5

SO we can determine the velocity soon after the reaction has started

Question 6

What is the equation to finding Vmax and Km ?

Answer 6

Km=(k-1+k2)/k1
Vmax=k2[E]T

Question 7

In the Lineweaver burke plots, What are the intercepts?

Answer 7

The x intercept is = -1/Km
The y intercept is = 1/Vmax

Question 8

What are both Km and Kcat the measure of?

Answer 8

Km is the measure of binding
Kcat is the measure of enzyme activity

Question 9

Kcat/Km- why is this the best measure of catalytic efficiency?

Answer 9

Because it takes into account both the rate of catalysis (Kcat) and the nature of the enzyme substrate interaction (Km)

Question 10

which step is the rate limiting step?

Answer 10

The k1, the rate of formation of the enzyme substrate complex is the rate limiting step

Question 11

What are sequential reactions?

Answer 11

The formation of a ternary complex consisting of the two substrates and the enzyme

Question 12

What is a double displacement reactions?

Answer 12

The formation of a substituted enzyme intermediate. aka ping pong reactions

Question 13

What do allosteric enzymes help with in metabolic pathways?

Answer 13

They control the flux of biochemical reactions in metabolic pathways

Question 14

What enzyme catalyzes the committed step of A to B of metabolic pathways and then what facilitates the B to F?

Answer 14

Allosteric enzymes-A to B
Michaelis Menten enzymes-B to F

Question 15

If there is too much F being made how is it inhibited ?

Answer 15

The F inhibits enzyme e1 by binding to a regulatory site on the enzyme that is distinct from the active site

Question 16

What are the two different quaternary structures that a Allosteric enzyme may exist in?

Answer 16

T-(tense) and R-(relaxed)

Question 17

T and R are in ______________ , with ____ being the more stable state
The ___ state is enzymatically more active than the ___ state
ALL active sites must be in the ________ state

Answer 17

Equilibrium , T
R , T
same

Question 18

what disrupted the R<–>T equilibrium when they bind the enzyme

Answer 18

Allosteric regulators

Question 19

What stabilizes the T state and what stabilize the R state ?

Answer 19

Inhibitor stabilize T state and activators stabilize the R state

Question 20

What is the disruption of the T<–>R equilibrium by substrates called ?

Answer 20

Homotropic effect

Question 21

What is the disruption of the T<–> equilibrium by regulators called ?

Answer 21

Heterotropic effect

Question 22

What does the sequential model for allosteric enzymes propose?

Answer 22

That the subunits undergo sequential changes structure
Meaning it starts with the T state and eventually changes to the R state as concentration rises