In aerobic respiration, cells use respiratory substrates such as glucose to make ATP. Events that happen during aerobic respiration include: the respiratory substrate is broken down into ever smaller molecules (catabolism); coenzymes participate in different reactions and, in some reactions, are reduced or oxidised; carbon dioxide is given off.
(a)[4]
Aerobic respiration takes place in four stages in order: glycolysis (G), the link reaction (LR), the Krebs cycle (KC) and oxidative phosphorylation (OP). Fill in Table 3.1 to indicate which events occur in each stage of aerobic respiration. Use a tick (\checkmark) to show that an event happens, or a cross (\times) to show that it does not happen.
(b(i))[4]
Explain how the device works out the respiratory quotient (RQ) value and how this indicates whether the cells are respiring mostly carbohydrates or lipids.
(b(ii))[3]
State the difference between the relative energy values of carbohydrates and lipids as respiratory substrates, and explain why that difference exists.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Catabolism occurs in glycolysis, link reaction, Krebs cycle but not oxidative phosphorylation” …