IB Biology HL C1.2 Cell respiration questions

Exam-style multiple choice and written questions with full markschemes. Check multiple choice answers straight away, or type, photograph or draw a written answer and get it marked.

Type
Multiple choiceWritten
Difficulty
EasyMediumHard

Question 1

Paper 2Easy6 marks

During aerobic respiration, electrons pass along the electron transport chain in the inner mitochondrial membrane. Answer the following questions about the proton gradient and ATP synthesis.

(a)

State how energy released as electrons pass along the electron transport chain is used, and state the direction in which protons are moved across the inner mitochondrial membrane.

[2]
(b)

State the difference in proton concentration across the inner mitochondrial membrane that results.

[1]
(c)

State the direction in which protons move through ATP synthase.

[1]
(d)

Explain how the movement of protons through ATP synthase results in ATP synthesis.

[2]

Question 2

Multiple choiceMedium1 mark

During aerobic respiration, a 3C pyruvate is processed before its acetyl group enters a cycle containing 4C oxaloacetate. Which description correctly links pyruvate processing to the carbon product and outputs of one cycle turn?

Show answer and explanation

Answer: D. Oxidative decarboxylation of 3C pyruvate leaves a 2C acetyl group. CoA transfers it to 4C oxaloacetate, forming 6C citrate; Krebs cycle oxidations and decarboxylations yield ATP and reduced NAD while regenerating oxaloacetate. A: gives the link reaction and citrate formation but stops before stating the cycle’s outputs and regeneration of oxaloacetate. B: reverses the redox direction; pyruvate is oxidized, not reduced. C: treats oxaloacetate as a net reactant, rather than a molecule regenerated by the cycle. Remember: acetyl groups enter the Krebs cycle by combining with oxaloacetate, which is then regenerated.

The best questions are still waiting

Unlock every question in this topic, then type, photograph or draw your answer and have it marked against the markscheme. Find out where you are dropping marks.

Unlock all questionsCompare Student and Student Plus