IB Biology HL 1.2.16 Oxygen as terminal electron acceptor Question Bank

Practise IB Biology HL 1.2.16 by applying oxygen as terminal electron acceptor concepts to exam-style questions.

Exam points

identify the relevant biological structure, process or evidence
apply the correct biological mechanism to the question
evaluate the result using data, adaptation or ecological reasoning

[Maximum number: 5]

Describe the role of oxygen in aerobic cell respiration.

a. terminal/final electron acceptor

b. at the end of electron transport chain

c. oxygen also accepts protons/hydrogen ions

d. water produced/ $\frac{1}{2} \mathrm{O}_{2}+2$ electrons $+2 \mathrm{H}^{+} \rightarrow \mathrm{H}_{2} \mathrm{O}$

e. helps to maintain proton gradient «across inner mitochondrial membrane by removal of protons from the stroma»

f. oxygen is highly electronegative/electrons strongly attracted to oxygen

g. avoids anaerobic respiration/buildup of lactic acid

h. allows more electrons to be delivered to the electron transport chain

OR allows NADFAD to be regenerated/reduced NAD/FAD converted back to NAD/FAD

i. oxygen allows maximum yield of energy «from glucose» allows complete oxidation of glucose/allows fats to be used in respiration

5 max

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C1.2.16 (HL)—Oxygen as terminal electron acceptor question 1