Explain why plant cells contain chloroplasts and mitochondria, but animal cells contain only mitochondria.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Mitochondria are the site of cellular respiration, producing ATP for the cell.
Both plant and animal cells require ATP, so both contain mitochondria.
Chloroplasts are the site of photosynthesis, converting light energy into chemical energy.
Only plant cells can photosynthesise, so only they need chloroplasts.
Both plant and animal cells require ATP, so both contain mitochondria.
Chloroplasts are the site of photosynthesis, converting light energy into chemical energy.
Only plant cells can photosynthesise, so only they need chloroplasts.
Examiner tips
- Use the term ‘site of respiration’ for mitochondria and ‘site of photosynthesis’ for chloroplasts. Show the link between energy needs and organelle presence. Keep the answer concise and directly address the comparison.
- common_mistakes
- :
- Confusing the functions of mitochondria and chloroplasts. Claiming animal cells have chloroplasts. Failing to mention the energy requirement of both cell types.
Mark scheme (4 marks)
- Mitochondria are the site of respiration
- Both plant and animal cells need energy / carry out respiration, so both need mitochondria
- Chloroplasts are the site of photosynthesis
- Animal cells cannot photosynthesise, so they do not need chloroplasts
Key terms in this question
Related
- Revision notes: Cell structure →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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