7 respiration - link reaction and krebs cycle

where does the link reaction take place?

in the mitochondrial matrix

what is transported into the mitochondrial matrix so the link reaction can be carried out?

pyruvate and NADH are actively transported

what are the stages of link reaction?

1. the pyruvate made in glycolysis is oxidised into acetate. NAD picks up the hydrogen and becomes NADH

2. acetate then combines with coenzyme A to produce acetylcoenzyme

how is carbon dioxide formed in the link reaction?

the hydrogen which is lost from pyruvate to oxidise it is picked up by NAD and reduces it to form NADH. as pyruvate is a 3 carbon molecule and acetate is only 2 carbon molecules, carbon dioxide is formed

what are the products made from the link reaction?

• 2x acetyl CoA

• 2x CO2 released

• 2x NADH

how many times does the link reaction occur for each glucose molecule?

twice

what happens in the krebs cycle?

1. acetyl-CoA reacts with a 4 carbon molecule, releasing coenzyme A and producing a 6 carbon molecule that enters the krebs cycle

2. in a series of redox reactions, the krebs cycle generates reduced coenzymes and ATP by subrate-level phosphorylation, and carbon dioxide is lost

what products are made from each cycle of the krebs cycle?

• 3x NADH

• 1x FADH

• 1x ATP

• 2x CO2

what products are made per glucose molecule in the krebs cycle?

• x6 NADH

• x2 FADH

• x2 ATP

• x4 CO2