Compare the role of the nucleus and the mitochondria in a eukaryotic cell, explaining how their functions contribute to the overall activity of the cell.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
The nucleus stores the cell’s DNA and controls gene expression, so it determines which proteins are made.
The mitochondria produce ATP through oxidative phosphorylation, providing the energy needed for cellular processes.
Thus the nucleus directs the cell’s activities by regulating protein synthesis, while the mitochondria supply the ATP that powers those activities.
The mitochondria produce ATP through oxidative phosphorylation, providing the energy needed for cellular processes.
Thus the nucleus directs the cell’s activities by regulating protein synthesis, while the mitochondria supply the ATP that powers those activities.
Examiner tips
- Use the exact terms ‘DNA storage’ and ‘energy production’
- Show the causal link: nucleus → gene expression → proteins; mitochondria → ATP → cellular work
- Keep answer concise – 4 points only
- Avoid extra detail such as ribosomes or cytoskeleton
Common mistakes
- Confusing the nucleus with the cytoplasm or ribosomes
- Describing mitochondria as ‘cell factories’ without mentioning ATP
- Failing to link the functions to overall cell activity
Mark scheme (4 marks)
- identification of the nucleus as the site of DNA storage
- identification of the mitochondria as the site of energy production
- explanation of how the nucleus controls the cell's activities
- explanation of how the mitochondria contribute to the cell's overall energy requirements