Q1. [3] medium initial-understanding
Distinguish between aerobic and anaerobic respiration in terms of: (i) where each occurs in the cell, (ii) the end products formed from pyruvate, and (iii) the relative amount of energy released.
Generated by claude-sonnet-4-6 · 2026-06-26 00:59 · grounding rag
Model Answer
| Feature | Aerobic Respiration | Anaerobic Respiration |
|---|---|---|
| (i) Location in cell | Pyruvate breakdown occurs in the mitochondria | Pyruvate breakdown occurs in the cytoplasm |
| (ii) End products from pyruvate | CO₂ and water | Ethanol + CO₂ (in yeast); Lactic acid (in muscle cells) |
| (iii) Energy released | Much greater amount of energy released | Much lesser amount of energy released |
Source: Life Processes, Section 5.3 Respiration
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Explanation
- Examiners look for all three points clearly distinguished for both types — missing any one costs a mark.
- A table format is ideal here; it shows the contrast clearly and saves words.
- Key detail: two anaerobic pathways exist — yeast (ethanol + CO₂) and muscle cells (lactic acid). Mentioning both strengthens the answer but either alone is acceptable.
- The location point is a favourite MCQ and short-answer target: cytoplasm = first step (common to both); mitochondria = aerobic continuation; cytoplasm = anaerobic continuation.