Class 7 Science Life Processes in Plants

Class 7 Science Life Processes in Plants

Chapter 10: Life Processes in Plants

Introduction

Plants, like animals, perform life processes such as nutrition, respiration, transportation, and reproduction. However, the mechanisms and structures in plants differ from animals. Understanding these processes is important for agriculture, ecology, and plant biology.

1. Nutrition in Plants

  • Plants are autotrophic – make their own food via photosynthesis.
  • Photosynthesis formula: 6CO2+6H2O+sunlight→C6H12O6+6O26CO_2 + 6H_2O + sunlight → C_6H_{12}O_6 + 6O_26CO2​+6H2​O+sunlight→C6​H12​O6​+6O2​
  • Chlorophyll in leaves absorbs sunlight.
  • Some plants are heterotrophic (e.g., Venus flytrap, fungi).

2. Respiration

  • Plants break down glucose to release energy.
  • Takes place in all cells.
  • Aerobic respiration: Requires oxygen → more energy
  • Anaerobic respiration: No oxygen → less energy

3. Transportation in Plants

  • Xylem: Transports water and minerals from roots → leaves
  • Phloem: Transports food (glucose) from leaves → other parts

4. Excretion in Plants

  • Waste products like oxygen, carbon dioxide, and resins are removed through:
    • Stomata: Gas exchange
    • Lenticels: Gas release in woody stems
    • Leaf fall: Removal of unwanted substances

5. Reproduction in Plants

  • Asexual reproduction: One parent, no gametes
    • Examples: Cutting, budding, vegetative propagation
  • Sexual reproduction: Involves flowers, pollination, fertilization → seeds
    • Example: Seed formation in flowering plants

6. Key Points to Remember

  • Plants make their own food by photosynthesis.
  • Energy is released by respiration.
  • Xylem and phloem transport water, minerals, and food.
  • Excretion occurs through stomata, lenticels, and leaf fall.
  • Reproduction can be asexual or sexual.

Questions – Life Processes in Plants

1. Very Short Answer (1 mark)

  1. Define autotrophic nutrition.
  2. Give the formula of photosynthesis.
  3. Name the green pigment in leaves.
  4. Name the tissue that transports water.
  5. Name the tissue that transports food.
  6. Give one example of asexual reproduction.
  7. Give one example of sexual reproduction.
  8. What is respiration in plants?
  9. How do plants excrete waste gases?
  10. Name a heterotrophic plant.

2. Multiple Choice Questions (MCQ)

  1. Plants make their food by:
    a) Respiration
    b) Photosynthesis
    c) Excretion
    d) Pollination
  2. Xylem transports:
    a) Food
    b) Water and minerals
    c) Carbon dioxide
    d) Oxygen
  3. Phloem transports:
    a) Water
    b) Food
    c) Oxygen
    d) Minerals
  4. Which pigment absorbs sunlight?
    a) Chlorophyll
    b) Xanthophyll
    c) Carotene
    d) Anthocyanin
  5. Pollination is a part of:
    a) Asexual reproduction
    b) Sexual reproduction
    c) Respiration
    d) Photosynthesis

3. Fill in the Blanks

  1. Plants that make their own food are called __________.
  2. Photosynthesis takes place in __________.
  3. Xylem carries __________ from roots to leaves.
  4. Phloem carries __________ from leaves to other parts.
  5. Stomata help in __________ of gases.

4. True/False Type

  1. Photosynthesis occurs in roots. (True/False)
  2. Plants perform respiration to release energy. (True/False)
  3. Phloem transports water. (True/False)
  4. Leaf fall helps in excretion. (True/False)
  5. Cutting is an example of asexual reproduction. (True/False)

5. Short Answer Questions (2–3 marks)

  1. Explain autotrophic nutrition in plants.
  2. Name two ways plants excrete waste.
  3. Give two differences between xylem and phloem.
  4. Give one example each of sexual and asexual reproduction in plants.
  5. Why is respiration important in plants?

6. Long Answer Questions (4–5 marks)

  1. Explain the life processes in plants with examples.
  2. Describe photosynthesis and its importance.
  3. Explain transportation in plants through xylem and phloem.
  4. Explain asexual and sexual reproduction in plants.
  5. Describe how plants remove waste from their body.

7. Higher-Order Thinking (HOT) & Application

  1. Why do desert plants have fewer stomata?
  2. Explain why phloem transports food in both directions.
  3. Compare asexual and sexual reproduction in terms of speed and variation.

8. Passage-Based Questions

Read the passage and answer:
Plants perform essential life processes like nutrition, respiration, transportation, excretion, and reproduction. Photosynthesis in leaves produces food. Xylem and phloem transport water, minerals, and food. Stomata and leaf fall help excrete wastes. Plants reproduce asexually and sexually.

  1. Name the tissues that transport water and food.
  2. Give one example of asexual reproduction.
  3. How do plants perform respiration?
  4. Why is photosynthesis important?

Answer Key – Life Processes in Plants

1. Very Short Answer

  1. Nutrition in which plants make their own food
  2. 6CO2+6H2O+sunlight→C6H12O6+6O26CO_2 + 6H_2O + sunlight → C_6H_{12}O_6 + 6O_26CO2​+6H2​O+sunlight→C6​H12​O6​+6O2​
  3. Chlorophyll
  4. Xylem
  5. Phloem
  6. Cutting
  7. Seed formation via flowers
  8. Breaking down food to release energy
  9. Through stomata and lenticels
  10. Venus flytrap

2. MCQ Answers

  1. b) Photosynthesis
  2. b) Water and minerals
  3. b) Food
  4. a) Chlorophyll
  5. b) Sexual reproduction

3. Fill in the Blanks

  1. Autotrophs
  2. Leaves
  3. Water and minerals
  4. Food
  5. Excretion

4. True/False

  1. False
  2. True
  3. False
  4. True
  5. True

5. Short Answer

  1. Plants absorb sunlight, carbon dioxide, and water to make food in leaves via photosynthesis.
  2. Stomata, lenticels, leaf fall
  3. Xylem – water/minerals, one direction; Phloem – food, both directions
  4. Asexual – cutting; Sexual – seeds from flowers
  5. Releases energy from stored food for growth and metabolism

6. Long Answer

  1. Life processes: Nutrition (photosynthesis), Respiration, Transport (xylem/phloem), Excretion, Reproduction
  2. Photosynthesis – converts light energy to chemical energy; produces oxygen
  3. Xylem – water/minerals, roots → leaves; Phloem – food leaves → other parts
  4. Asexual – one parent, quick, identical; Sexual – two parents, variation, slower
  5. Excretion through stomata, lenticels, and leaf fall

7. HOT & Application

  1. Fewer stomata reduce water loss in deserts
  2. Phloem carries food to roots, fruits, and growing parts → bidirectional
  3. Asexual – fast, identical; Sexual – genetic variation, slower

8. Passage-Based

  1. Xylem – water; Phloem – food
  2. Cutting
  3. By breaking down glucose in cells
  4. Produces food and oxygen for survival