Aerobic respiration occurs when oxygen is available. A much greater energy yield is obtained from aerobic respiration than from respiration in anaerobic conditions.

Mark scheme

Marking points from the official mark scheme (May/June 2022). The mark or mark type is shown in brackets.

1. [4] any four from: accept ora 1 pyruvate converted to, acetyl group / 2C group / acetyl CoA (in link reaction); 2 NAD needed (in link reaction); 3 (where) NAD becomes reduced ; 4 reduced NAD goes to ETC ; 5 ETC / oxidative phosphorylation, works if oxygen is present or oxygen is the final electron acceptor; 6 (so) reduced NAD is oxidised / NAD is regenerated;
2. [5] any five from: 1 glycolysis; 2 phosphorylation of glucose ; 3 splitting of fructose (1,6) bi(s)phosphate / AW ; 4 (into) two, triose phosphate / TP ; 5 (TP) oxidised / dehydrogenated, to pyruvate ; 6 net 2 ATP / 4 ATP, produced ; 7 (2) reduced NAD produced;