A bacterial cell is a prokaryotic cell. Explain why bacterial cells do not have mitochondria yet are still able to carry out cellular respiration.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Bacteria are single-celled organisms that lack many of the membrane-bound organelles found in eukaryotic cells. Despite this, bacteria are able to release energy and remain active.
Model answer (4 marks)
Mitochondria are the site of aerobic respiration in eukaryotic cells.
Bacterial cells are prokaryotic and therefore lack membrane‑bound organelles, including mitochondria, and they do not have a nucleus.
Cellular respiration is a universal process that occurs in all living cells.
In bacteria the enzymes and reactions of cellular respiration take place in the cytoplasm, so they can still carry out respiration without mitochondria.
Bacterial cells are prokaryotic and therefore lack membrane‑bound organelles, including mitochondria, and they do not have a nucleus.
Cellular respiration is a universal process that occurs in all living cells.
In bacteria the enzymes and reactions of cellular respiration take place in the cytoplasm, so they can still carry out respiration without mitochondria.
Examiner tips
- Use the exact terms ‘mitochondria’, ‘prokaryotic’, ‘cytoplasm’, and ‘cellular respiration’.
- Show the logical link: lack of mitochondria → reactions in cytoplasm → respiration still possible.
Common mistakes
- Confusing mitochondria with chloroplasts or other organelles.
- Forgetting to mention that respiration is universal to all cells.
Mark scheme (4 marks)
- Mitochondria are the site of aerobic respiration in eukaryotic cells
- Bacterial cells are prokaryotic and do not contain membrane-bound organelles / do not have a nucleus
- Cellular respiration is a process that occurs in all living cells / is universal
- Bacteria can still carry out cellular respiration because the enzymes and reactions required occur in the cytoplasm rather than in mitochondria
Key terms in this question
cellular respiration · mitochondria · prokaryotic
Related
- Revision notes: Cell structures →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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