Lecture 11: Citric Acid Cycle

Question 1

What does the citric acid cycle do?

Answer 1

• completely oxidize the 2-C acetyl group to 2 CO2 with dehydrogenases (removes a hydrogen)
• Along the way you generate 3 NADH, 1 FADH2 (reduced electron carriers), and 1 GTP=ATP

Question 2

How is FAD?H different from NADH

Answer 2

• FADH is different from NADH based on its redox potential.

- FADH2 is more positive, so electrons flow in that direction from FAD

Question 3

Electron Transport chain

Answer 3

• occurs in the inner membrane of the mitochondrion (membranes of christae- more SA)
• transforms NADH to ATP
• consists of a series of redox reactions
• NADH gives up a proton and becomes NAD+ (complex I)
• FADH2 becomes FAD (gives up electrons) when in contact with complex II- has less energy so no proton can be pumped at this step.
• This causes conformation change in the protein that allows to move the proton across the gradient