Biology 9700 · AS & A Level · Respiration

Respiration — practice question

Fig. 8.1 shows several stages of glucose metabolism in mammalian cells.
(a(i))[1]

Using Fig. 8.1, identify the cell part where glucose is changed into pyruvate.

(a(ii))[2]

Using Fig. 8.1, explain why pyruvate must be converted to lactate when oxygen is absent.

(a(iii))[1]

Using Fig. 8.1, identify the enzyme that catalyses the conversion of pyruvate to lactate.

(a(iv))[2]

Using Fig. 8.1, name the reaction type and the kind of bonds formed when glucose molecules are joined to make glycogen.

(b)[4]

Describe how anaerobic respiration in yeast cells is different from anaerobic respiration in mammalian cells.

(c(i))[2]

The respiratory quotient (RQ) is used to work out which respiratory substrate, such as carbohydrate or lipid, an organism is using at a given time. State how the RQ is calculated.

(c(ii))[2]

State the usual RQ values for the respiration of carbohydrates and lipids.

(c(iii))[1]

Suggest what would happen to the RQ value when respiration changes to anaerobic.

Worked solution & mark scheme

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