Link Reaction

Question 1

Why is it called link reaction?

Answer 1

Because it links glycolysis with Krebs Cycle

Question 2

Why pyruvate

Answer 2

Pyruvate, the end product from glycolysis, still contains a great deal of chemical potential energy which can be used to make more ATP. When free oxygen is present, pyruvate will enter the krebs cycle and oxidative phosphorylation to generate ATP. However, it first need to enter link reaction in the mitochondria’s matrix.

Question 3

How pyruvate enter the mitochondria

Answer 3

Pyruvate enter the mitochondria by active transport, from cytoplasm to outer membrane to inner membrane and finally at the matrix.

Question 4

steps

Answer 4

1. Decarboxylation and dehydrogention of pyruvate ito form acetyl group
2. Acetyl group combines with coA to form acetyl coA

Question 5

final products

Answer 5

• 2 acetyl coA
• 2 co2
• 2 NAD reduced

Question 6

formula

Answer 6

pyruvate + NAD + coA = CO2 + NAD reduced + acetyl coA

Question 7

role of acetyl coA

Answer 7

• A coenzyme is a complex molecule that helps enzyme to carry it their function by enhancing its action or activating it but it is not used in the reaction
• in the link reaction, coenzyme A combines with acetyl group to from acetyl coA
• It carries acetyl A to the krebs cycle to continue aerobic respiration

Question 8

Fatty acid relation

Answer 8

Fatty acid from fat metabolism can also produce acetyl coA. Fatty acids breaks down in mitochondrion in a cycle of reactions in which at every turn the fatty acid is reduce by a 2 carbon acetyl unit. These combined with coA forms acetyl CoA and is transferred to krebs cycle to continue the respiration

Question 9

coenzyme structure

Answer 9

a nucleotide (adenine and ribose) and vitamin B5(pantothenic acid)