Life Processes, Types of Life Process in Plants and Animals, Explanation, MCQS, Questions Answers, Worksheet, Test Paper

ANAND CLASSES study material and notes to learn the essential Life Processes—Nutrition, Respiration, Transport, Excretion, Growth, and Reproduction—for JEE, NEET, and CBSE Class 10 exams. Get a detailed explanation, MCQs, conceptual questions, worksheets, and test papers for a complete study experience.

Introduction to Life Processes

All living organisms perform essential functions to maintain life, collectively known as life processes. These processes ensure survival, growth, and reproduction. Without life processes, organisms cannot sustain themselves and eventually perish.

The main life processes are:

• Nutrition – The intake and utilization of food.
• Respiration – The breakdown of food to release energy.
• Transport – The movement of substances within the organism.
• Excretion – The removal of waste materials.
• Control & Coordination – The response to environmental stimuli.
• Growth – The increase in size and mass of an organism.
• Movement – The ability to move body parts or the whole body.
• Reproduction – The production of offspring.

Detailed Explanation of Life Processes

1. Nutrition

• Nutrition is the process of acquiring food and converting it into energy.
• It provides raw materials for growth, repair, and energy production.
• Two main types of nutrition:
  • Autotrophic Nutrition:
    • Performed by green plants, algae, and some bacteria through photosynthesis.
    • Requires sunlight, chlorophyll, carbon dioxide, and water.
    • The equation for photosynthesis: $$6CO_2 + 6H_2O + Light \rightarrow C_6H_{12}O_6 + 6O_2$$
  • Heterotrophic Nutrition:
    • Organisms depend on others for food.
    • Includes herbivores (plant-eaters), carnivores (meat-eaters), and omnivores (both plant and meat-eaters).
    • Three modes:
      • Holozoic Nutrition – Ingestion, digestion, absorption (e.g., humans, animals).
      • Saprotrophic Nutrition – Decomposers digest externally (e.g., fungi, bacteria).
      • Parasitic Nutrition – Organisms live on or inside a host (e.g., tapeworm, lice).

2. Respiration

• Respiration releases energy stored in food in the form of ATP (Adenosine Triphosphate).
• Two types:
  • Aerobic Respiration:
    • Requires oxygen.
    • Glucose breakdown occurs completely.
    • Produces 36 ATP molecules.
    • Occurs in mitochondria.
  • Anaerobic Respiration:
    • Does not require oxygen.
    • Glucose breakdown is incomplete.
    • Produces only 2 ATP molecules.
    • Occurs in some microorganisms and human muscles during vigorous activity (lactic acid formation).
• The equation for aerobic respiration: $$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + Energy$$

3. Transport

• The movement of essential substances within an organism.
• In plants:
  • Xylem transports water and minerals from roots to leaves.
  • Phloem distributes food (sugars) throughout the plant.
• In animals:
  • The circulatory system consists of the heart, blood, and blood vessels.
  • Blood carries oxygen, nutrients, hormones, and waste products.

4. Excretion

• Removal of metabolic waste to maintain homeostasis.
• In humans:
  • Kidneys filter blood to remove urea and other waste products (urine formation).
  • Skin removes salts and water (sweating).
  • Lungs expel carbon dioxide.
• In plants:
  • Remove waste gases (O₂, CO₂) through stomata.
  • Excrete excess water via transpiration.

5. Control & Coordination

• Organisms respond to environmental stimuli for survival.
• In animals:
  • Nervous System: The brain, spinal cord, and nerves regulate voluntary and involuntary actions.
  • Endocrine System: Hormones regulate growth, metabolism, and reproduction.
• In plants:
  • Use hormones such as auxins, gibberellins, and cytokinins.
  • Tropisms (growth responses) include phototropism (light), geotropism (gravity), and thigmotropism (touch).

6. Growth

• Increase in size and number of cells.
• In plants, growth is indeterminate and occurs at specific points (meristems).
• In animals, growth is determinate and stops after a certain age.

7. Movement

• Animals move to find food, escape predators, and reproduce.
• Plants exhibit movement such as bending towards light (phototropism) and closing of leaves in Mimosa pudica.

8. Reproduction

• Essential for species survival.
• Two types:
  • Asexual reproduction – Involves a single parent (e.g., binary fission in bacteria, budding in Hydra).
  • Sexual reproduction – Involves male and female gametes (e.g., humans, flowering plants).

Difference between Plants and Animals Life Processes

Important difference between the life processes of plants and animals are as follows :

MCQs (Multiple Choice Questions)

1. Which organelle is known as the powerhouse of the cell?
   • (a) Nucleus
   • (b) Mitochondria ✅
   • (c) Ribosome
   • (d) Chloroplast
2. What is the primary function of the xylem?
   • (a) Transport food
   • (b) Transport water ✅
   • (c) Transport oxygen
   • (d) Transport waste

Conceptual Questions

1. Why do plants need transpiration? Answer: Transpiration helps in cooling, nutrient transport, and maintaining water balance.
2. How does respiration differ from breathing? Answer: Respiration is the biochemical process of energy release, while breathing is the physical intake of oxygen.

Do You Know?

• The human heart beats about 100,000 times per day.
• The longest nerve in the human body is the sciatic nerve.
• Cyanobacteria were the first organisms to perform photosynthesis.
• Plants lose 90% of absorbed water through transpiration.

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