Biochemistry

Question 1

What is the First Law of Thermodynamics?

Answer 1

Energy cannot be created or destroyed

Question 2

What is the Second Law of Thermodynamics?

Answer 2

When energy is converted from one form to another, some of that energy becomes unavailable to do work

Question 3

What is enthalpy?

Answer 3

Heat content (H)

Question 4

What is entropy?

Answer 4

Disorder (S)

Question 5

What is an exergonic reaction?

Answer 5

One in which the total free energy of the products is less than the total free energy of the reactants
DeltaG negative
Spontaneous

Question 6

What is an endergonic reaction?

Answer 6

One in which the total free energy of the products is greater than the total free energy of the reactants
DeltaG positive
Cannot occur spontaneously

Question 7

What is Vmax?

Answer 7

The maximal velocity of an enzyme

Question 8

What is Km?

Answer 8

The substrate concentration where the initial reaction is half-maximal

Question 9

When 1/[V] is plotted against 1/[S], what is Vmax?

Answer 9

The intersection of the straight line with the y-axis

Question 10

When 1/[V] is plotted against 1/[S], what is Km?

Answer 10

The intersection with the X axis

Question 11

When a competitive inhibitor is added what happens to the plot of 1/[V] against 1/[S]?

Answer 11

Vmax does not change but Km varies

The y-intercept stays the same but the x-intercept varies

Question 12

When a non-competitive inhibitor is added what happens to the plot of 1/[V] against 1/[S]?

Answer 12

Vmax decreases but Km stays the same

The y-intercept increases but the x-intercept stays the same

Question 13

Is the anabolism oxidation or reduction?

Answer 13

Reduction

Question 14

Is catabolism oxidation or reduction?

Answer 14

Oxidation

Question 15

Name the 3 fates of glucose

Answer 15

Ribose-5-phosphate
Lactate
Pyruvate

Question 16

Describe glycolysis

Answer 16

glucose –> fructose-1,6-bisphosphate –> 2 triose phosphates –> 2 pyruvate
Net gain 2 ATP and 2NADH

Question 17

Name the 3 enzymes which control glycolysis and what their function is

Answer 17

Hexokinase - substrate entry
Phosphofructokinase - rate of flow
Pyruvate kinase - product exit

Question 18

How is pyruvate metabolised to acetyl-coA?

Answer 18

Pyruvate dehydrogenase complex (PDC)

Question 19

Where are the enzymes of the TCA cycle located?

Answer 19

In the mitochondria

Question 20

What does each turn of the TCA cycle require?

Answer 20

Uptake of acetyl-coA

Question 21

What does each turn of the TCA cycle produce?

Answer 21

2 CO2
2 NADH
1 FADH2

Question 22

How is ATP produced in oxidative phosphorylation?

Answer 22

Energy from electrons are used to pump protons from the mitochondrial matrix to the intermembrane space
Protons flow back into the mitochondrial matrix via ATPase, producing ATP

Question 23

How is NADH from the cytoplasm transported into the mitochondria?

Answer 23

The malate-aspartate shuttle