Lecture 5: Aerobic Respiration

Question 1

What are the 4 steps in Aerobic Respiration, and where do they occur?

Answer 1

1. Glycolysis- Cytosol
2. Pyruvate Oxidation- Mitochondrial Matrix
3. Tricarboxylic Acid Cycle- Mitochondrial Matrix
4. Oxidative Phosphorylation- Inner mitochondrial membrane

Question 2

What are the inputs and outputs of Glycolysis?

Answer 2

Inputs: Glucose, ADP, Pi, NAD+

Outputs: Pyruvate, H+, NADH, ATP

Question 3

What are the inputs and outputs of Pyruvate oxidation? What catalyzes Pyruvate oxidation?

Answer 3

Inputs: Pyruvate, Coenzyme A, NAD+

Outputs: Acetyl CoA, CO2, NADH, H+

Pyruvate dehydrogenase complex catalyzes pyruvate oxidation.

Question 4

What are the inputs and outputs of Tricarboxylic Acid Cycle?

Answer 4

Inputs: Acetyl CoA, H2O, NAD+, FAD+, ADP, Pi

Outputs: FADH, CO2, ATP, NADH, H+, Coenzyme A

Question 5

What are the inputs and outputs of Oxidative Phosphorylation?

Answer 5

Inputs: ADP, Pi, O2, NADH

Outputs: ATP, NAD+, H+, H2O

Question 6

What does the uncoupling do?

What is the name of the uncoupling protein, and where is it found?

When is uncoupling good vs bad?

Answer 6

Uncoupling is when protons flow down their conc. gradient, but not through the F1F0 ATPase, resulting in heat production rather than ATP production.

UCP1 is found in brown adipose/fat.

It is bad when it is used as a diet aid because it can lead to the generation of excessive heat and early death.

It is good for hibernation and infants.

Question 7

What are the 2 Phases in Glycolysis?

Answer 7

Energy Investment: ATP hydrolysis occurs to activate the glucose molecule for subsequent breakdown.

Energy payoff: More ATP is generated as well as NADH and pyruvate

Question 8

How is the synthesis of ATP during oxidative phosphorylation an example of coupling reactions?

Answer 8

You are coupling ATP production (positive ΔG) with chemiosomosis (negative ΔG).

Question 9

How does the Proton gradient created by the proton pumps drive ATP Production?

Answer 9

Protons will flow passively into the matrix. This chemiosmosis leads to the rotation of the F1F0 ATPase, which usually catalyzes the hydrolysis of ATP. The rotation reverses the activity leading to ATP synthesis.

Question 10

What gets oxidized and reduced in Aerobic respiration?

Answer 10

Glucose gets oxidized, and Oxygen gets reduced.

Question 11

What are the 2 phases of oxidative phosphorylation?

Answer 11

ETC: Electrons from NADH oxidation moves through each proton pump, and H+ gets pump into the inter membrane space.

Chemiosmosis: H+ flowing back into the F1F0 ATPsynthase.