Plant Physiology
Photosynthesis, respiration, transport, growth hormones
Key Concepts
- Photosynthesis: light reactions (in thylakoid) + Calvin cycle (in stroma)
- C3 plants: fix CO₂ via RuBisCO into 3-PGA; C4 plants use Hatch-Slack pathway
- Respiration: glycolysis (cytosol) → Krebs cycle (matrix) → ETC (inner mitochondrial membrane)
- Transpiration: loss of water vapour from leaves; drives water up xylem
- Plant hormones: auxin (elongation), gibberellin (stem elongation), cytokinin (cell division), ABA (stress), ethylene (ripening)
Important Formulae
| Net photosynthesis equation | 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (light energy) |
| Aerobic respiration (net ATP) | 1 glucose → ~36–38 ATP |
| Glycolysis (net) | 1 glucose → 2 pyruvate + 2 ATP + 2 NADH |
Quick Tips
- RuBisCO is the most abundant enzyme on Earth; fixes CO₂ in the Calvin cycle.
- CAM plants (cacti, succulents) open stomata at night to reduce water loss.
- Phloem transports sugars (source to sink); xylem transports water and minerals (unidirectional, root to leaf).
Sample Practice Questions
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Stomata open when guard cells:
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Answer: Gain turgidity (absorb water)
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Auxin promotes cell elongation. It is produced mainly at:
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Answer: Apical meristem (shoot tip)
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The movement of water from roots to leaves is called:
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Answer: Ascent of sap
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Ethylene is a gaseous plant hormone that promotes:
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Answer: Fruit ripening and leaf abscission
Practice Questions
Practice 20 randomly selected NEET questions on Plant Physiology. Answers are revealed after each question.
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What are the key concepts in Plant Physiology for NEET?
Photosynthesis: light reactions (in thylakoid) + Calvin cycle (in stroma); C3 plants: fix CO₂ via RuBisCO into 3-PGA; C4 plants use Hatch-Slack pathway; Respiration: glycolysis (cytosol) → Krebs cycle (matrix) → ETC (inner mitochondrial membrane); Transpiration: loss of water vapour from leaves; drives water up xylem; Plant hormones: auxin (elongation), gibberellin (stem elongation), cytokinin (cell division), ABA (stress), ethylene (ripening).
Which formulae are important for Plant Physiology in NEET?
Net photosynthesis equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (light energy); Aerobic respiration (net ATP): 1 glucose → ~36–38 ATP; Glycolysis (net): 1 glucose → 2 pyruvate + 2 ATP + 2 NADH.
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