4.1.5 Uses of Glucose from Photosynthesis

Uses of Glucose in Plants:

1. Respiration: Glucose is broken down to release energy.
2. Storage: Converted into insoluble starch for storage in roots, stems, and leaves.
3. Production of Fats/Oils: Used to produce fat or oil for storage, particularly in seeds.
4. Cellulose Production: Glucose is converted into cellulose to strengthen cell walls.
5. Protein Synthesis: Combined with nitrates (absorbed from the soil) to form amino acids, which then produce proteins.

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Respiration:

• Respiration occurs in every cell in the body and is the process of transferring energy from glucose, enabling living processes to occur.
• All living organisms undergo respiration.
• Respiration is exothermic as energy is transferred to the environment.
• Respiration can occur aerobically (with oxygen) or anaerobically (without oxygen).

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Aerobic Respiration	Anaerobic Respiration
• Uses oxygen. • Yields the most energy. • Most reactions take place in the mitochondria. Chemical equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O • Glucose = C₆H₁₂O₆ • Oxygen = O₂ • Carbon dioxide = CO₂ • Water = H₂O	• Occurs when there is insufficient oxygen. • Yields less energy than aerobic respiration. • Used as a last resort, e.g., during intense exercise when oxygen intake is limited. • Incomplete oxidation of glucose. In animals: C₆H₁₂O₆ → Lactic acid In plants and yeast (fermentation): C₆H₁₂O₆ → Ethanol + CO₂ • This reaction is used in making bread and alcoholic drinks.