Life Processes and Nutrition: Essential Biology Concepts

Life Processes

Life processes are the processes that are necessary for an organism to stay alive. Examples include nutrition and respiration.

Criteria of Life

• Growth
• Movement

Nutrition

Nutrition is the process in which an organism takes in food, utilizes it to get energy for growth, repair, maintenance, etc., and excretes the waste materials from the body.

Types of Nutrition

1. Autotrophic Nutrition

(Auto = self; trophos = nourishment) Examples: Plants, Algae, Blue-green bacteria.

• Process: Photosynthesis (Photo = light; Synthesis = to combine)
• Raw Materials:
  • Carbon dioxide
  • Water
• Energy Conversion: Light/Solar energy to Chemical energy
• Role of Chlorophyll: To trap the sun's energy for photosynthesis
• Factors for Autotrophic Nutrition:
  • Carbon dioxide
  • Water
  • Light
  • Temperature
• Events/Steps of Photosynthesis:
  • Absorption of light energy by chlorophyll
  • Conversion of light energy to chemical energy and splitting of water molecules into Hydrogen and Oxygen
  • Reduction of Carbon dioxide to Carbohydrate
• Gaseous Exchange:
  • Gas Used: Carbon dioxide
  • Byproduct: Oxygen
• Source of Raw Materials:
  • Carbon Dioxide: Land plants - Air, Aquatic plants - Water
  • Water & Minerals: Soil

2. Heterotrophic Nutrition

(Hetero = others; trophos = nourishment) Examples: Animals, plants lacking chlorophyll like fungi.

• (a) Saprophytic Nutrition: Organisms feed on dead, decaying plant or animal material. Examples: Fungi, Bacteria
• (b) Parasitic Nutrition: Organisms obtain food from the body of another living organism (host)
  • Endoparasite: Parasite lives inside the body of the host. Examples: Tapeworm, Roundworm.
  • Exoparasite: Parasite lives on the body of the host. Examples: Lice, Leech.

  Note: The parasite benefits while the host is usually harmed. Examples: Cuscuta - plant parasite (amar bel), Plasmodium (malarial parasite).

• (c) Holozoic Nutrition: Organisms (mostly animals) take in whole food and then digest it into smaller particles with enzymes. Examples: Amoeba, Paramecium, Animals, Human beings.

Steps in Holozoic Nutrition

• Ingestion: Taking in of food.
• Digestion: Breaking down of complex food into simpler, absorbable form.
• Assimilation: Utilization of digested food from the body.
• Egestion: Removing undigested food from the body

Nutrition in Human Beings

Alimentary Canal:

Mouth → Esophagus → Stomach → Small intestine → Large intestine

Common Features of Respiratory Organs

• Large Surface Area: For a greater rate of diffusion of respiratory gases.
• Thin Permeable Walls: To ensure easy diffusion and exchange of gases.
• Extensive Blood Supply: Respiratory organs are richly supplied with blood vessels for quick transport of gases.