The Krebs Cycle

Question 0

What are the 7 stages of the Krebs cycle?

Answer 0

1. Acetyl CoA splits into Acetate and CoA - the CoA returns to the link reaction.
2. 2C Acetate combines with the 4C Oxaloacetate to form 6C Citrate.
3. Citrate is decarboxylated (forming CO2) and dehydrogenated into a 5C compound
   ↪️(The H+ ions are used to reduce NAD to NADH).
4. The 5C compound is decarboxylated (forming CO2) and dehydrogenated into a 4C compound
   ↪️(The H+ ions are used to reduce NAD into NADH).
5. The 4C compound is changed into ANOTHER 4C compound. The energy released is used to phosphorylate ADP into ATP by substrate level phosphorylation.
6. The 4C compound is dehydrogenated into another 4C compound.
   ↪️(The H+ is used to reduce FAD into FADH2)
7. The 4C compound is DEHYDROGENATED (oxidised) into OXALOACETATE.
   ↪️(The H+ ions are used to reduce NAD into NADH)

Question 1

Where does the Krebs cycle take place?

Answer 1

Mitochondrial matrix

Question 2

What are the products produced in the Krebs cycle per glucose molecule?

Answer 2

• 6x NADH
• 4x CO2
• 2x ATP
• 2x FADH2

Question 3

What are the total number of products produced per glucose molecule in all 3 stages?

Answer 3

• 10x NADH
• 6x CO2
• 4x ATP
• 2x FADH2