A-LevelBiologyHomeostasis9700/41 · Oct/Nov 2025 · Q96 Marks

(a) Fig. 9.1 shows a longitudinal section of a human kidney. [Figure 9.1] Name the regions of the kidney labelled X and Y in Fig. 9.1. X Y (b) A biosensor can be used to measure the concentration of glucose in urine. Outline how a biosensor measures the concentration of glucose in urine.

(a)Name the regions of the kidney labelled X and Y in Fig. 9.1. X Y[2]
(b)A biosensor can be used to measure the concentration of glucose in urine. Outline how a biosensor measures the concentration of glucose in urine.[4]

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Mark scheme

Marking points from the official mark scheme (Oct/Nov 2025). The mark or mark type is shown in brackets.

[1] (a) (X =) (renal) pelvis ;
[1] (Y =) medulla ;
[4] (b) any four from: 1 glucose oxidase (present / immobilised, in sensor / on strip) ; 2 glucose → hydrogen peroxide ; 3 hydrogen peroxide (oxidised) → oxygen / electrons ; 4 (magnitude of) e– flow / current / voltage, (generated) is proportional to, hydrogen peroxide / glucose, concentration ; 5 digital / numerical / quantitative, reading / result / value (on screen) ; 6 AVP;

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