Aerobic respiration detail: pyruvate is oxidised to acetate producing reduced NAD in the link reaction; acetate combines with coenzyme A to produce acetylcoenzyme A; acetylcoenzyme A reacts with a four-carbon molecule releasing coenzyme A and producing a six-carbon molecule entering the Krebs cycle; in a series of oxidation-reduction reactions the Krebs cycle generates reduced coenzymes and ATP by substrate-level phosphorylation and carbon dioxide is lost; synthesis of ATP by oxidative phosphorylation is associated with electron transfer down the electron transfer chain and passage of protons across inner mitochondrial membranes catalysed by ATP synthase (chemiosmotic theory); other respiratory substrates include breakdown products of lipids and amino acids entering the Krebs cycle
After glycolysis, cells break down pyruvate further inside the mitochondria. This releases energy to make large amounts of ATP through a chain of reactions ending at the inner mitochondrial membrane.
Formula
1 Glucose → 2 ATP (glycolysis) + 2 ATP (Krebs) + ~34 ATP (oxidative phosphorylation)
Real World
Peter Mitchell won the 1978 Nobel Prize in Chemistry for proposing chemiosmosis — proving that the proton gradient across the inner mitochondrial membrane, not a direct chemical reaction, drives ATP synthase.
Exam Focus
For 'describe' questions, link each stage to its location — matrix for Krebs, inner membrane for oxidative phosphorylation.
Evaluation Scaffold
A four-step framework for high-quality evaluation. Use this for 'assess', 'evaluate', and 'to what extent' questions.
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