Respiration- The krebs cycle

Question 1

What does the Kreb cycle consist of?

Answer 1

a series of enzyme-controlled reactions

Question 2

What is the 1st step of the Kreb cycle?

Answer 2

Acetyl CoA (2C) comes from the link reaction

Question 3

What is acetyl CoA formed from?

Answer 3

from fatty acids (after the breakdown of lipids) and amino acids

Question 4

What is the 2nd step of the Kreb cycle?

Answer 4

4 carbon (4C) oxaloacetate accepts the 2C acetyl fragment from acetyl CoA to form the 6 carbon (6C) citrate (Coenzyme A is released in this reaction)

Question 5

What is the 3rd step of the Kreb cycle?

Answer 5

Citrate is then converted back to oxaloacetate through redox reactions
Decarboxylation of citrate
Releasing 2 CO2 as waste gas

Question 6

What is the 4th step of the Kreb cycle?

Answer 6

Oxidation (dehydrogenation) of citrate
Releasing H atoms that reduce coenzymes NAD and FAD

Question 7

What is the 5th step of the Kreb cycle?

Answer 7

Oxidation (dehydrogenation) of citrate
Releasing H atoms that reduce coenzymes NAD and FAD

Question 8

What is the 6th step of the Kreb cycle?

Answer 8

Substrate-linked phosphorylation-
Phosphate is transferred to ADP, forming 1 ATP