BIOC2303

Question 0

Define Kcat?

Answer 0

The turnover number, the number of times each enzyme site converts substrate to product per unit time. Expressed in the inverse of the time units of the Y axis.

Question 1

Define Km?

Answer 1

The Michaelis-Menten Constant, has the same units as x. It is the substrate concentration to achieve a half-maximum enzyme velocity.

Question 2

Define Et?

Answer 2

The concentration of enzyme catalytic sites. Units: concentration per time.

Question 3

Define Vmax?

Answer 3

Maximum enzyme velocity, same units as Y.

Question 4

On an inverse velocity vs. substrate graph what would the slope be?

Answer 4

Km/Vmax

Question 5

On an inverse velocity vs. substrate graph what would the y-intercept be?

Answer 5

1/Vmax

Question 6

On an inverse velocity vs. substrate graph what would the x-intercept be?

Answer 6

-1/Km

Question 7

What is an inverse velocity vs. substrate graph called?

Answer 7

Lineweaver-Burk plot

Question 8

Define Kd for a simple association reaction and it’s relation to Ka?

Answer 8

1/Ka = Kd = [R][L] / [R:L]

Question 9

What is the Michaelis-Menten equation?

Answer 9

Vmax x [S] / Km + [S]

Question 10

What does Kcat/Km measure?

Answer 10

The specificity/catalytic efficiency of an enzyme.

Question 11

What do higher Kcat/Km values mean?

Answer 11

The better the enzyme works on the substrate (higher specificity) and the more efficient the enzyme is.

Question 12

Give the equilibrium constant equation?

Answer 12

Keq= [A][B] / [AB]

Question 13

Define Ki?

Answer 13

The concentration of inhibit which is required to decrease the maximal rate of the reaction to half of the inhibited value in the presents of low substrate concentration.

Question 14

How can you find Ki on a graph?

Answer 14

Look at the point in which all of the lines cross on an inverse velocity vs. inhibitor concentration graph.

Question 14

What is the equation that links Ki to IC50?

Answer 14

IC50/1 + ([S]/Km)

Question 15

Define IC50?

Answer 15

Half maximal inhibitory concentration, a measure of the effectiveness of a substrate in inhibiting. The [I] required to inhibit by 1/2.

Question 16

During competitive inhibition what happens to the Vmax and Km?

Answer 16

The Vmax is constant and the Km varies.

Question 17

During non competitive inhibition what happens to the Vmax and Km?

Answer 17

The Vmax varies and the Km is constant.

Question 18

During un competitive inhibition what happens to the Vmax and Km?

Answer 18

Both the Vmax and Km varies.

Question 19

During competitive inhibition how does the inhibitor bind?

Answer 19

It’s structurally similar to the substrates and competes for the active site.

Question 20

During non competitive inhibition how does the inhibitor bind?

Answer 20

The inhibitor does not structurally resemble the substrate and it binds to free enzyme or enzyme: substrate at a site where substrate does not.

Question 21

During un competitive inhibition how does the inhibitor bind?

Answer 21

The inhibitor does not structurally resemble the substrate and it binds to the enzyme: substrate only. This may be the active site but substrate binding is required first.

Question 22

What is 1Co in kelvin?

Answer 22

274.15

Question 23

What is avogadros constant?

Answer 23

6.02 x10^23

Question 24

How do you use avogadros constant to find the number of molecules in number of moles?

Answer 24

Times avogadros by the moles

Question 25

How do you use avogadros constant to find the number of moles in a molecules?

Answer 25

Divide molecules by avogadros.

Question 26

Give the scale of meter units?

Answer 26

cm, um, nm, pm, fm etc