Sources of food cbse class 6 science

Lesson 1: Sources of Food

FOOD: It is the substance consumed to provide nutritional support for the body. FUNCTIONS OF FOOD:

  1. It provides energy.
  2. It helps to overcome wear and tear of cells.
  3. It helps in growth and development.
  4. It protects the body against diseases.

INGREDIENTS OF FOOD: An edible substance that is used in making a dish. Eg: Ingredients of porridge are oats, milk, water, salt, dry fruits etc.


  1. Plants

Eg: Fruits oils, vegetables, spices, etc.

  • Animals

Eg: Milk, Egg, Honey, Meat Etc.


  1. ENERGY GIVING FOOD: Food which provides energy.

Eg: Carbohydrates :- Sources: Cereals, tubers, sugar etc.

Fats :- Sources : Oils, ghee

  • BODY BUILDING FOODS: Foods which helps in growth and repair of worn out tissues.

Eg: Proteins

Sources: Pulses, eggs, meat, milk etc.

  • PROTECTIVE FOOD: Foods which protect us from diseases. Eg: Vitamins and minerals

Sources: Vegetables and Fruits.


  1. Milk is considered as complete diet. Give reason.Milk is considered as complete diet as it contains almost the nutrients like carbohydrates, proteins, fats, vitamins and minerals in it.
  • Plants always take the first step in the food chain. Give reason.As green plants are producers which prepare their own food and consumers depend on plants directly or indirectly for food.

EDIBLE PARTS: The parts of a plant or an animal that is eaten or consumed.

s.noEdible partExamples
1RootCarrot, turnip, raddish etc.
2StemPotato, ginger, sugarcane etc.
3LeavesBasil, mint, coriander etc
4FlowerCauliflower broccoli rose etc.
5BudClove, bauhinia, cardoon etc.

APICULTURE: The method of rearing honey bee on large scale for the sake of honey.

PISCICULTURE: The method of rearing fishes on large scale for the sake of meat.

POULTRY ANIMALS: Animals which provide both meat and eggs are called poultry animals.

  1. PRODUCERS: Organisms which prepare their own food in the presence of sunlight and do not depend on other organisms.

Eg: Green plants

Green plants make their own food by the process of PHOTOSYNTHESIS.

6CO2    +      6H2O       —-  ———–>       CHOLOROPHYLL         ————>     C6H12O6 + 6O2

6CO2 = CARBON DIOXIDE  +  6H2O=WATER                                       C6H1206 = GLUCOSE  + 602 = OXYGEN