A student says: 'Anaerobic respiration in yeast and anaerobic respiration in human muscle cells are the same…

Question

A student says: 'Anaerobic respiration in yeast and anaerobic respiration in human muscle cells are the same process.' Is this correct? Explain the key similarity and the key difference between the two.

Accepted Answer

## Model Answer The student is **not correct**. The two processes are similar but not identical. **Key Similarity:** Both are anaerobic processes (occur without oxygen). In both, glucose is first broken down to pyruvate in the cytoplasm. **Key Difference:** In yeast, pyruvate is converted to **ethanol and carbon dioxide**. In human muscle cells, pyruvate is converted to **lactic acid** (a three-carbon molecule). The build-up of lactic acid in muscles causes cramps during sudden activity. *Source: Life Processes, Section 5.3 Respiration* --- ## Explanation - Examiners expect you to clearly state the verdict (not correct), then give one similarity and one difference — all three earn separate marks. - The similarity (anaerobic, pyruvate as common intermediate) and the difference (end products: ethanol + CO₂ vs lactic acid) are directly from the textbook passage. - Naming the end products precisely is essential — vague answers lose marks.

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