Nutrition in Plants — Previous Year Questions (Class 7 Science)
Understand photosynthesis, modes of nutrition, and plant nutrition. Explore how plants manufacture their own food.
TL;DR: Understand photosynthesis, modes of nutrition, and plant nutrition. Explore how plants manufacture their own food.
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Understand photosynthesis, modes of nutrition, and plant nutrition. Explore how plants manufacture their own food.
Nutrition in Plants — Previous Year Questions with Solutions
Q (2023, 3 marks): What is photosynthesis? Write the equation for photosynthesis.
Answer: Photosynthesis is the process by which green plants manufacture their own food using sunlight, water, and carbon dioxide.
Equation: 6CO2 + 6H2O + Sunlight → C6H12O6 + 6O2
Organelles involved: Chloroplast (contains chlorophyll)
Q (2022, 3 marks): Differentiate between autotrophs and heterotrophs. Give examples.
Answer: Autotrophs: Organisms that make their own food. Examples: Plants, algae, photosynthetic bacteria.
Heterotrophs: Organisms that depend on others for food. Examples: Animals, fungi, humans.
Plants are autotrophs; animals are heterotrophs.
Q (2023, 2 marks): What are the raw materials and products of photosynthesis?
Answer: Raw materials: Carbon dioxide (CO2) and water (H2O), with sunlight as energy source.
Products: Glucose (C6H12O6) and oxygen (O2).
Oxygen is released as waste.
Q (2022, 3 marks): Why are plants green? Explain the role of chlorophyll.
Answer: Plants are green because of the pigment chlorophyll in their leaves.
Role of chlorophyll:
1. Absorbs light energy from the sun
2. Captures sunlight for photosynthesis
3. Makes food in the chloroplasts
4. Gives the plant its green color
Q (2023, 4 marks): Name two parasitic plants and two saprophytic plants. Explain their modes of nutrition.
Answer: Parasitic plants: Cuscuta, mistletoe
Mode: Feed on host plants without giving anything in return; absorb nutrients from host.
Saprophytic plants: Fungi, mushrooms
Mode: Feed on dead and decaying organic matter; break it down and absorb nutrients.
Q (2022, 3 marks): What would happen to plants if there were no chloroplasts?
Answer: Without chloroplasts:
1. Photosynthesis cannot occur
2. Plants cannot manufacture food
3. No glucose production
4. Plants would starve and die
5. Oxygen production would stop
Chloroplasts are essential for plant survival.
Frequently Asked Questions
Do all plants contain chlorophyll?
No, not all plants contain chlorophyll. Parasitic plants like cuscuta and saprophytic plants like fungi do not contain chlorophyll and cannot perform photosynthesis. They depend on other organisms for food.
Can photosynthesis occur without sunlight?
No, photosynthesis cannot occur without sunlight. Sunlight provides the energy needed for the process. Light-dependent reactions require photons to drive electron excitation and ATP/NADPH production.
More Class 7 Science PYQs
- Chemical Reactions and Equations
- Light (Reflection and Refraction)
- Electricity
- Acids, Bases and Salts
- Metals and Non-metals
- Life Processes
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