Generated by claude-sonnet-4-6 · 2026-06-11 09:53 · grounding rag
Model Answer
(a) Labelled diagram of stomatal pore:
```
Guard cell Guard cell
\ /
======[ OPEN PORE ]======
(Chloroplasts present in guard cells)
======[CLOSED PORE]======
| |
Guard cell Guard cell
(flaccid) (flaccid)
```
(Draw two kidney-shaped guard cells — one pair showing an open pore between them, another pair tightly pressed together showing a closed pore. Label: guard cells, stomatal pore, epidermal cells.)
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(b) Main events during photosynthesis:
- Absorption of light energy by chlorophyll present in chloroplasts.
- Splitting of water molecules (photolysis) into hydrogen and oxygen using light energy; oxygen is released as a by-product.
- Conversion of CO₂ into glucose (carbon fixation) using the absorbed light energy and hydrogen from water.
---
(c) Balanced chemical equation for photosynthesis:
$$6CO_2 + 6H_2O \xrightarrow{\text{Sunlight, Chlorophyll}} C_6H_{12}O_6 + 6O_2$$
Carbon dioxide + Water → Glucose + Oxygen
---
Explanation
- For (a): Draw clearly; examiners award marks for correct labels — guard cells, stomatal pore, epidermal cells — and showing both open and closed states. Neat diagrams score full marks even without artistic perfection.
- For (b): Three events (absorption of light, photolysis of water, carbon fixation/glucose formation) are the key points examiners look for. Mentioning chlorophyll and chloroplasts adds accuracy.
- For (c): The equation must be balanced (6CO₂, 6H₂O, C₆H₁₂O₆, 6O₂) and must show sunlight and chlorophyll as conditions above the arrow. Missing conditions or an unbalanced equation loses marks.