Chapter 7 Kinetics and Regulation

Question 1

What is the first order reaction, and what is the proportionality constant unit?

Answer 1

• This is when the velocity of a reaction is directly proportional to reactant concentration and it uses the units s^-1

Question 2

What is the second order reaction’s proportionality constant units?

Answer 2

its per molar per second, M^-1s^-1

Question 3

How is enzyme kinetics measured ?

Answer 3

When you measure velocity as a function of substrate concentration with a fixed amount of enzyme

Question 4

What is the difference between K1 and K^-1 and K2

Answer 4

-K1 is how fast the enzyme binds
-K^-1 is how fast the Enzyme disassociates
-K2 is how fast the substrate is converted into product

Question 5

How is initial velocity determined ?

Answer 5

• it is determined by measuring product formation as a function of time and then determining the velocity soon after the reaction has started

Question 6

What is the Michaelis Menten equation

Answer 6

V0=Vmax([S]/[S]+Km)
-and we ignore the bottom [S] if it is much much smaller than the Km.

Question 7

What is the Lineweaver Burk equation?

Answer 7

1/Vo=Km/Vmax*1/S+1/Vmax

Question 8

k2 is also known as ?

Answer 8

kcat

Question 9

If [E]T is known what equation is useable ?

Answer 9

Vmax=k2[E]T

Question 10

If the [S]«Km, what can we assume about the [E]T

Answer 10

we can assume that free enzyme [E]~[E]T

Question 11

Kcat/Km is a measure of ______________

Answer 11

catalytic efficiency

Question 12

The _______Kcat over the _________ the Km better the result. We always want a ________Kcat and a ________ Km

Answer 12

Higher, smaller,Higher,smaller

Question 13

What is the rate limiting step?

Answer 13

The rate of formation of the enzyme substrate complex,K1

Question 14

Diffusion limits the value of K1 around what value

Answer 14

~10^8-10^9 s^-1M^-1

Question 15

-What are sequential reactions?

Answer 15

It is a formation of ternary complex consisting of thee two substrates and the enzyme

Question 16

What are double displacement reactions? What are the also known as?

Answer 16

it is a formation of a substituted enzyme intermediate, they are also known as ping-pong reactions

Question 17

What are allosteric enzymes and what do they do?

Answer 17

-They are catalysts and information Sensors
-it controls the flux of biochemical reactions in metabolic pathways
- Without them metabolic chaos would occur

Question 18

What allows the allosteric enzyme to do generation of complex metabolic pathways ?

Answer 18

Their regulatory properties allow for that

Question 19

_________________catalyze the committed step of metabolic pathways,________________ facilitate the remaining steps

Answer 19

Allosteric enzymes, Michaelis Menten enzymes

Question 20

How does the synthesizes of F get regulated?

Answer 20

By the feedback inhibition , it sends a message to A when there is too much F being made and it eventually inhibits the process.

Question 21

How does the pathway product F inhibit enzyme e1

Answer 21

it binds to the regulatory site on the enzyme that is distinct from the active site

Question 22

Which type of model describes the behavior of allosteric enzyme

Answer 22

The concerted model

Question 23

What are the features of the concerted model

Answer 23

-The enzyme exists in two different quaternary structures, designated T(tense) and R(relaxed)
-T and R are in equilibrium , with T being the more stable state
-The R state is enzymatically more active than the T state
-All active sites must be in the same state

Question 24

What will help favor the conversion of more enzymes to the R state.

Answer 24

The disruption of T<–>R equilibrium by the binding of substrate

Question 25

Which state will most enzymes be in as concentration increases?

Answer 25

The R(relaxed) state

Question 26

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

Answer 26

Allosteric regulators

Question 27

What stabilizes the T and R state

Answer 27

-Inhibitors stabilize T state
-Activators stabilize R state

Question 28

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

Answer 28

Homotropic effect

Question 29

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

Answer 29

Heterotropic effect

Question 30

What is the sequential model

Answer 30

it is a model for allosteric enzymes that proposes subunits undergo sequential changes in the structure