Life Processes

Chapter Summary

Life Processes

Processes necessary to maintain life are called life processes.

Examples: Nutrition, respiration, transport of materials and excretion.

Types of Nutrition

Autotrophic Nutrition: It involves taking simple inorganic materials from environment and using external source of energy to make complex high-energy organic material.

Heterotrohic Nutrition: It involves taking complex material prepared by other organisms.

Nutrition in Humans

Nutrition in human being is composed of ingestion, digestion, absorption, assimilation and egestion.

Human digestive system is composed of an alimentary canal and some accessory glands.


Breaking down of organic compounds to release energy in the form of ATP is called respiration.

Aerobic respiration happens in presence of oxygen, but anaerobic respiration does not need oxygen.

Aerobic respiration is more efficient than anaerobic respiration.

Circulatory System

This system is responsible for transport of materials (oxygen, carbon dioxide, food, waste, etc.) in the body.

Circulatory system is composed of blood, blood vessels and heart.

Transport in Plants

Vascular tissues in plants are responsible for transport of water, minerals, food and other materials.

Xylem is responsible for transport of water and minerals.

Phloem is responsible for transport of food.

Excretory System

This system is composed of a pair of kidneys, a pair of ureters and a urinary bladder.

Nephrons in kidneys filter waste materials from blood.

Excretion in Plants

Plants use many methods to get rid of waste materials.

Waste material may be stored in vacuoles as gum and resin.

Waste material may be removed in the falling leaves, or excreted into the soil.