DP Biology (first assessment 2025)

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Question 20N.2.HL.TZ0.3b

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Date November 2020 Marks available [Maximum mark: 4] Reference code 20N.2.HL.TZ0.3b
Level HL Paper 2 Time zone TZ0
Command term Explain Question number b Adapted from N/A
b.
[Maximum mark: 4]
20N.2.HL.TZ0.3b
(b)

Explain how ATP is generated in mitochondria by chemiosmosis.

[4]

Markscheme

a. protons pumped across inner membrane of mitochondria/into intermembrane space;

b. using energy released by flow of electrons/by electron transport/by electron carriers;

c. proton gradient established/maintained / proton motive force generated;

d. protons pass/diffuse back through inner membrane/membrane of cristae/to matrix;

e. through ATP synthase;

f. ATP production coupled to flow of protons / ATP from ADP and Pi using energy from protons;

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