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Class 10 Science Life Processes notes card
Class 10 Science

Life Processes – Class 10 – Notes

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These notes include all the important points, concepts and topics from Life Processes – Science – CBSE class 10. The special feature of these notes is that you will also get many important questions related to the corresponding topics, previous year questions (PYQs) along with their answers!

Nutrition

Definition: Nutrition is the process by which organisms obtain energy and raw materials from nutrients such as carbohydrates, proteins, and fats. These nutrients are essential for growth, repair, and maintenance of the body.

Types of Nutrition:

  1. Autotrophic Nutrition:
    • Photosynthesis:
      • Have you ever wondered how plants manage to feed themselves? It’s pretty amazing actually! They have this incredible process called photosynthesis where they use sunlight, air (specifically carbon dioxide), and water to create their own food.
      • Definition: Green plants synthesize their food using sunlight, carbon dioxide, and water. Chlorophyll in the leaves captures sunlight, converting it into chemical energy, resulting in the production of glucose and oxygen.
      • Important Question: Explain the process of photosynthesis.
        • Answer: Photosynthesis is the process by which green plants synthesize food from carbon dioxide and water using sunlight. Chlorophyll in the leaves captures sunlight, converting it into chemical energy, resulting in the production of glucose and oxygen.
          Example: The equation for photosynthesis is 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.
      • Chemosynthesis: Certain bacteria can actually create their own food by using energy from inorganic substances (things like rocks and minerals)! It’s like they’re little chemists, whipping up meals out of non-living stuff.
        • Example: Bacteria in deep-sea hydrothermal vents use sulfur compounds to produce organic molecules
  2. Heterotrophic Nutrition:
    • Holozoic: Involves ingestion, digestion, absorption, assimilation, and egestion (e.g., humans).
    • Saprophytic: Organisms feed on dead and decaying matter (e.g., fungi).
    • Parasitic: Organisms derive nutrition from a host (other living organisms e.g., tapeworms).

Previous Year Question:

  • Question: Differentiate between autotrophic and heterotrophic nutrition.
  • Answer: Some organisms make their own food. This is called autotrophic nutrition. They use processes like photosynthesis. Other organisms cannot make their own food. They depend upon other organisms to obtain their food. This is called heterotrophic nutrition.

Respiration

Definition: Respiration is the biochemical process in which cells obtain energy by breaking down glucose molecules. This process is essential for providing energy required for various cellular activities.

Types of Respiration:

  1. Aerobic Respiration:
    • Occurs in the presence of oxygen.
    • Produces a significant amount of energy (ATP).
    • Equation: C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy.
      • Important Question: Write the chemical equation for aerobic respiration.
        Answer: C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy.
      • Example: Aerobic respiration in humans throughout the day. To keep going, human cells use aerobic respiration – a process that uses oxygen to turn food into energy. (That’s what powers every step we take, every word we speak, and everything else we do each day.)
  2. Anaerobic Respiration:
    • Occurs in the absence of oxygen.
    • Produces less energy.
    • Equation: C6H12O6 → 2C2H5OH + 2CO2 + Energy (in yeast).
      • Example: Anaerobic respiration in muscles during intense exercise, leading to the production of lactic acid. (This lactic acid is what causes the cramps after exercise)

Notes:

  • Aerobic respiration requires oxygen, while anaerobic respiration does not.
  • Fermentation is a type of anaerobic respiration occurring in yeast.

Previous Year Question:

  • Question: Compare aerobic and anaerobic respiration in terms of energy yield and end products.
  • Answer: Human body has two ways of making energy from food:
    • Aerobic (With air): Aerobic respiration makes a lot of energy, but it needs oxygen. It also creates water and carbon dioxide, which we breathe out.
    • Anaerobic (Without air): Anaerobic respiration makes less energy and doesn’t need oxygen. It can produce lactic acid or alcohol, along with carbon dioxide. (The lactic acid produced in this reaction makes the muscles sore after intense workout.)

Transportation

Definition: Transportation is the movement of substances like water, minerals, and nutrients within an organism.

This process is vital for distributing essential compounds to different parts of the body.

Transportation in Plants:

  1. Xylem:
    • Transports water and minerals from roots to other parts.
      • Important Question: What is the role of xylem in plants?
        Answer: Xylem is responsible for transporting water and minerals from the roots to various parts of the plant.
  2. Phloem:
    • Transports food (sugars) from leaves to other parts.
      • Important Question: Describe the function of phloem in plants.
        Answer: Phloem transports the synthesized food (sugars) from the leaves to other parts of the plant.

Transportation in Animals:

  1. Circulatory System:
    • Heart, blood, and blood vessels form the circulatory system.
    • Transports oxygen, nutrients, and waste products.
      • Important Question: Explain the double circulation in human beings.
        Answer: Double circulation refers to the separate pathways for oxygenated and deoxygenated blood in the human heart. The right side pumps deoxygenated blood to the lungs (pulmonary circulation), while the left side pumps oxygenated blood to the rest of the body (systemic circulation).
  2. Lymphatic System:
    • Transports lymph, a fluid containing white blood cells.
      • Example: The lymphatic system helps in immune responses and the removal of interstitial fluid.

Notes:

  • The heart has four chambers: two atria and two ventricles.
  • Arteries carry blood away from the heart; veins carry blood to the heart.

Previous Year Question:

  • Question: What are the components of the human circulatory system?
  • Answer: The human circulatory system consists of the heart, blood, and blood vessels (arteries, veins, and capillaries).

Excretion

Definition: Excretion is the process of removing metabolic waste from the body.

This is crucial for maintaining homeostasis (balance among all the body systems to function correctly). Excretory system also prevents any damage to the body due to excess accumulation of waste material.

Excretion in Humans:

  1. Kidneys:
    • Filter blood to produce urine, removing urea and other wastes.
      • Important Question: What is the role of kidneys in excretion?
        Answer: Kidneys filter waste products and excess substances from the blood, producing urine which is then excreted from the body.
  2. Lungs:
    • Expel carbon dioxide and water vapor.
      • Example: Breathing out CO2 during respiration.
  3. Skin:
    • Removes waste through sweat.
      • Example: Sweating removes excess salts and water from the body.

Excretion in Plants:

  1. Stomata and Lenticels:
    • Help in removing gases.
      • Example: Oxygen and carbon dioxide exchange through stomata.
  2. Guttation:
    • Excretion of excess water.
      • Example: Water droplets seen at the tips of grass blades in the morning.

Notes:

  • Nephrons are the functional units of the kidney.
  • Sweat glands in the skin help in the removal of excess salts and water.

Previous Year Question:

Question: Explain how the human excretory system works.
Answer: The human excretory system primarily consists of kidneys, ureters, bladder, and urethra. Kidneys act as filters, removing waste products from the blood to produce urine. This urine flows through ureters (tubes) into the bladder for storage. Urine is expelled from the body via the urethra.

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