link reaction

what is the link reaction?

the process by which a pyruvate is converted to acetyl CoA ( i think this flashcard set explains it using 1 pyruvate)

what’s the “1st” step in the link reaction?

the pyruvate will travel to the matrix of a mitochondrion via active transport. so, the link reaction occurs in the matrix of the mitochondrion

what happens to the pyruvate?

the pyruvate is oxidised/dehydrogenated & decarboxylated

what is the link reaction?

it’s oxidative decarboxylation, meaning a carboxyl group is removed from a molecule, while electrons are transferred to the coenzyme NAD

what happens next to the pyruvate?

it undergoes oxidative decarboxylation, meaning a carbon dioxide molecules is removed, and a hydrogen is removed.

the hydrogen is then transferred to the coenzyme NAD, to reduce it and become NADH

what is the new product?

one 2-carbon acetate

what happens to the product?

it’ll attach/combine to the molecule coenzyme A to form 1 acetyl CoA molecule.

idk where exactly, but somewhere in the link reaction, metabolised lipids are broken down into 2 carbon-acetyl groups, which’ll be transferred by coenzyme A to the Krebs Cycle

what is the net yield & the waste product?

net yield: 2 Acetyl CoA per glucose molecule

Carbon dioxide is removed from the pyruvate & is a waste product

can fatty acids be used in aerobic respiration?

yes, they can. since they hv a long chain of carbon atoms, CoA can oxidise this chain & break it down. it makes Acetyl CoA with 2 carbons & carries them to the Krebs Cycle. Glycolysis isn’t needed, but reaction is much slower.