Coh3 compound name

8.1.4  Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron transport chain and the role of oxygen

Aerobic respiration takes place in the mitochondria, using the pyruvate produced via glycolysis

It produces large amounts of ATP in the presence of oxygen via three main processes:

The Link Reaction

Pyruvate is transported from the cytosol to the mitochondrial matrix in a reaction that produces (one) NADH + H+ via oxidation

The pyuvate loses a carbon (as CO2) and the remaining two carbons are complexed with coenzyme A (CoA) to form acetyl CoA

The Krebs Cycle

In the matrix, acetyl CoA combines with a 4C compound to form a 6C compound

Over a series of reactions the 6C compound is broken back down into the original 4C compound

These reactions result in the formation of 2 CO2 molecules, 1 ATP molecule and multiple hydrogen carriers, specifically 3 (NADH + H+) and 1 FADH2

The Electron Transport Chain

The hydrogen carriers (NADH + H+ and FADH2) provide electrons to the electron transport chain on the inner mitochondrial membrane

As the electrons cycle through the chain they lose energy, which is used to translocate H+ ions to the intermembrane space (creating a gradient)

The hydrogen ions return to the matrix through the transmembrane enzyme ATP synthase, producing multiple ATP molecules (via chemiosmosis)

Oxygen acts as a final electron acceptor for the electron transport chain, allowing further electrons to enter the chain

Oxygen combines the electrons with H+ ions to form water molecules (~32 out of 36 ATP molecules)