Electron transport chain

Question 1

Chemiosmotic coupling contains two stages - which are they?

Answer 1

Stage 1: Protons are pumped through the membrane due to the electrical gradient that build up from the ETC

Stage 2: The gradient that builds up is being used to help the protons enter the ATP synthase ( ADP –> ATP)

Question 2

How many complexes does the ETC contain?

Answer 2

4

Question 3

What does a Heme-group contain?

Answer 3

1 iron, 4 nitrogen

Question 4

What is a Ubiquinone?

Answer 4

An electron carrier molecule (hydrophobic). Carrier electrons from complex 1&2 –> 3

Question 5

What is a Cytochrome C?

Answer 5

An electron carrier molecule. Carries electrons from complex 3 –> 4

Question 6

What is a cardiolipid?

Answer 6

A lipid that only exists in the membrane. Keeps the different complexes together.

Question 7

How does the proton move inside of the membrane?

Answer 7

Due to Proton-wires. Rows of polar / ionic side chains. Jumps from one side to the other.

Question 8

ATP- synthase needs a two units difference pH-gradient to work. This is not the case though. How come it still works?

Answer 8

The Christae “captures” protons and keeps them –> results in a bigger difference in pH

Question 9

What is an ADT/ATP carrier protein?

Answer 9

Protein that allows ADT and APT to enter/leave the matrix/membrane

Question 10

How many ATP does the whole procedure result in?

Answer 10

Approx 30-32 ATPs (majority –> NADH that later becomes ATP through oxidative phosphorylation

Question 11

What is an UCP3 (uncoupling protein)?

Answer 11

Important protein - a shortcut for protons. Allows them to go through the membrane straight away, without going through the ATP synthase.

The energy of oxidation of lipids instead becomes heat (important for bears during winter)