5- link reaction and the Krebs cycle

Question 1

information on link reaction

Answer 1

• Takes place in the mitochondrial matrix.
• A preparatory step that connects glycolysis with the Krebs cycle.

Question 2

products from 1 pyruvate in link reaction

Answer 2

• 1x acetyl CoA.
• 1x NADH.
• 1x CO2.
• If considering the products from 1 glucose, this is doubled.

Question 3

process of link reaction

Answer 3

Pyruvate from glycolysis undergoes decarboxylation (removal of a carbon atom) and oxidation (electron loss) to form an acetyl group. The acetyl group is then attached to coenzyme A, producing acetyl CoA. During this process, NAD+ is reduced to NADH.

Question 4

diagram of link reaction

Answer 4

Question 5

information on Krebs cycle

Answer 5

Takes place in the mitochondrial matrix.

Question 6

products from 1 acetyl CoA in Krebs cycle

Answer 6

• 1x ATP.
• 1x FADH2.
• 3x NADH.
• 2x CO2.
• If considering the products from 1 glucose, this is doubled.

Question 7

process of Krebs cycle

Answer 7

1. Acetyl CoA reacts with oxaloacetate to form a 6C compound called citrate.
2. The 6C citrate is decarboxylated to a 5C compound, releasing 1 NADH and 1 coz.
3. The 5C compound is decarboxylated to a 4C compound, releasing 1 NADH and 1 CO2.
4. The 4C compound gets oxidised to oxaloacetate, releasing 1 ATP, 1
   FADH2, and 1 NADH.

Question 8

diagram of Krebs cycle

Answer 8