With the help of a schematic flow chart, show the breakdown of glucose in a cell to provide energy –
Generated by claude-sonnet-4-6 · 2026-06-11 09:47 · grounding rag
Model Answer
Breakdown of glucose in a cell:
Glucose (6-carbon)
↓ (Glycolysis — in cytoplasm)
Pyruvate (3-carbon)
(i) In the presence of oxygen (Aerobic respiration):
Pyruvate → (mitochondria, using O₂) → CO₂ + H₂O + Energy (ATP) (large amount)
(ii) In lack of oxygen (Anaerobic respiration):
- In yeast: Pyruvate → Ethanol + CO₂ + Energy (ATP)
- In muscle cells: Pyruvate → Lactic acid + Energy (ATP)
Source: Chapter 5, Section 5.3 — Respiration
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Explanation
- The examiner expects a flow chart / schematic, not a paragraph. Use arrows to show the pathway.
- The common first step — glucose → pyruvate (glycolysis, in cytoplasm) — must be shown for full marks.
- Two anaerobic pathways are expected: yeast (ethanol + CO₂) and muscle cells (lactic acid). Mentioning both strengthens the answer.
- Key location details (cytoplasm for glycolysis, mitochondria for aerobic) add precision but are secondary to the pathway itself.
- Keep the flow chart neat and labelled; this is what earns marks in board exams.