IB Biology SL 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.

Question 1

Paper 2Medium16 marks

Researchers cultured equal numbers of the same type of animal cell under identical conditions, supplying a different carbon compound to each group. They measured the rates of ATP synthesis and oxygen uptake.

Carbon compound suppliedATP synthesis rate (relative units min⁻¹ per 10⁶ cells)Oxygen uptake rate (µmol min⁻¹ per 10⁶ cells)
None added2.01.0
Glucose8.04.0
Fatty acids6.05.0
(a)

Calculate the percentage increase in ATP synthesis rate when glucose is supplied compared with when no carbon compound is added. Show your calculation.

[3]
(b)

State which of glucose or fatty acids gives the higher ATP synthesis rate, and state the difference between their rates.

[2]
(c)

Explain how energy from cell respiration can be transferred to active transport through the interconversion of ATP and ADP.

[4]
(d)

Distinguish between gas exchange and cell respiration.

[2]
(e)

A student claims that oxygen uptake is a direct measure of the rate of ATP synthesis. Evaluate this claim using the data, and identify two limitations of the evidence.

[5]

Question 2

Multiple choiceHard1 mark

The schematic shows solute transfer between equal-sized compartments and two interconversions of ATP. Which interpretation correctly describes the energy transfers?

Compartment 1Compartment 2solute movementtransport proteinATPADP + phosphateXY
Show answer and explanation

Answer: D. The solute moves from a compartment with fewer particles to an equal-sized compartment with more particles, so it moves against the concentration gradient and requires energy. At X, ATP is hydrolysed to ADP and phosphate, releasing energy that can drive this transport. At Y, ATP is synthesized from ADP and phosphate, which requires an energy input.
A: reverses the energy changes for both ATP hydrolysis and ATP synthesis.
B: correctly identifies energy release at X but reverses the energy requirement for ATP synthesis.
C: correctly identifies the energy input for ATP synthesis but treats ATP hydrolysis as requiring energy input.
Remember: ATP hydrolysis releases energy; ATP synthesis requires energy.

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