Enzyme Kinetics

Question 1

How can we follow the rate of a reaction?

Answer 1

By looking at the appearance of product or disappearance of substrate.

Question 2

In enzyme kinetics, what is K?

Answer 2

The proportionality constant between the velocity and the concentrations of the reactants.

Question 3

What is velocity defined as?

Answer 3

The (positive) change in concentration of products over time
or
The (negative) change in concentration of substrate over time

Question 4

At constant temperature, what is the rate of a reaction proportional to?

Answer 4

The frequency at which the reactant molecules come together

Question 5

In the Michaelis Menton reaction, what is V _max ?

Answer 5

The maximum rate of the reaction at saturated substrate concentration

Question 6

In the Michaelis Menton reaction, what is K_m?

Answer 6

The substrate concentration that gives half of the maximum rate of reaction.

Question 6

In the Michaelis Menton reaction, what is K_m?

Answer 6

The substrate concentration that gives half of the maximum rate of reaction.

Question 7

If a substrate has a lower K_m, does it have a stronger or lower affinity than a substrate with a higher K_m?

Answer 7

The substrate with the lower K_m has a greater affinity for the enzyme.

Question 8

If a substrate has a higher K_m, does it have a stronger or lower affinity than a substrate with a lower K_m?

Answer 8

The substrate with the higher K_m has a lower affinity for the enzyme.

Question 9

What type of plot is used to easily determine V_max?

Answer 9

A Lineweaver-Burk plot
or
A Double Reciprocal plot

Question 10

In the Lineweaver-Burk plot, at what point is the K_m found?

Answer 10

At the point where the line crosses the x-axis

Question 11

In the Lineweaver-Burk plot, at what point is the V_max found?

Answer 11

At the point where the line crosses the y-axis

Question 12

What does a Double Reciprocal plot look like when there is competitive inhibition of an enzyme?

Answer 12

The lines all meet at the same point on the y-axis or on the right-hand side of the x-axis

Question 13

What does a Double Reciprocal plot look like when there is uncompetitive inhibition of an enzyme?

Answer 13

The lines cross the y-axis in a perpendicular fashion

Question 14

What does a Double Reciprocal plot look like when there is mixed inhibition of an enzyme?

Answer 14

The lines all meet at the same point on the left-hand side of the y-axis