Science · Class 7
Nutrition in Plants
Photosynthesis, modes of nutrition, and soil nutrients for plants.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Photosynthesis equation: CO₂ + H₂O → (sunlight/chlorophyll) → glucose + O₂
Green plants are autotrophs — they synthesise food using CO₂, water, sunlight, and chlorophyll. This chapter also covers saprotrophs, parasites, insectivorous plants, and how nutrients are replenished in soil.
Photosynthesis
- Raw materials: CO₂ (stomata) + water (roots)
- Products: glucose + oxygen
- Occurs in green parts, mainly leaves
- Chlorophyll traps solar energy
Other Modes of Nutrition
- Parasites: Cuscuta (amarbel) — no chlorophyll, climbs host
- Insectivorous: pitcher plant, Venus flytrap — nitrogen from insects
- Saprotrophs: fungi — feed on dead matter
- Symbiotic: Rhizobium bacteria in legume root nodules fix nitrogen
Soil Fertility
- Nitrogen, phosphorus, potassium absorbed by roots
- Crop rotation and legumes restore nitrogen
- Fertilisers and manure add nutrients
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Photosynthesis equation
List raw materials and products of photosynthesis.
- 1CO₂ from air through stomata
- 2Water from soil through xylem
- 3Glucose stored as starch; O₂ released
Answer
CO₂ + H₂O → (sunlight/chlorophyll) → glucose + O₂
Nutrition mode
Classify: mushroom, green plant, Cuscuta.
- 1Mushroom — saprotroph
- 2Green plant — autotroph
- 3Cuscuta — parasite on host
Answer
Saprotroph, autotroph, parasite respectively
Key Points to Remember
- ✓ Stomata allow gas exchange in leaves
- ✓ Lichens: algae + fungi living together
- ✓ Heterotrophs depend on others for food
Exam Tips
- • Draw labelled leaf cross-section showing stomata
- • Give examples of parasitic and insectivorous plants
- • Write word equation for photosynthesis
Practice MCQs — Nutrition in Plants
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Plants that make their own food are: