Class-6 Science Notes- Chapters 1&2
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Class-6 Science Notes- Chapters 1&2

Chapter 1- Summary

  • There is a lot of variation in the food eaten in different regions of India.
  • The main sources of our food are plants and animals.
  • Animals which eat only plants are called herbivores.
  • Animals which eat only animals are called carnivores.
  • Animals which eat both plants and animals are called omnivores.

Chapter 2- Summary

  • Each dish is usually made up of one or more ingredients, which we get from plants or animals.
  • These ingredients contain some components that are needed by our body. These components are called nutrients.
  • The major nutrients in our food are carbohydrates, proteins, fats, vitamins and minerals.
  • In addition, food contains dietary fibres and water which are also needed by our body.
  • There are many types of carbohydrates. The main carbohydrates found in our food are in the form of starch and sugars.
  • Test for starch: If we put a few drops of dilute iodine solution on a food item, then a change in colour of the food item to blue-black indicates the presence of starch in it.
  • Test for protein: food item + 10 drops of water + 2 drops of copper sulphate solution + 10 drops of solution of caustic soda(sodium hydroxide). A violet colour indicates the presence of proteins in the food item.
  • Test for fats: An oily patch on paper, after rubbing the food item on it, confirms the presence of fats in the food item.

What do various nutrients do for our body?

  • Carbohydrates mainly provide energy to our body.
  • Fats also give us energy. In fact, fats give much more energy as compared to the same amount of carbohydrates.
  • Foods containing proteins are often called ‘body-building foods’.
  • Vitamins help in protecting our body against diseases. They also help in keeping our eyes, bones, teeth and gums healthy.
  • Vitamin-A: for skin and eyes.
  • Vitamin-C: helps in fighting against diseases. It gets easily destroyed by heat during cooking.
  • Vitamin-D: helps our body to use calcium for bones and teeth.
  • Minerals are needed by our body in small amounts.
  • Each one is essential for proper growth of body and to maintain good health. Example: Iodine, Phosphorous, Iron and Calcium.
  • Our body also needs dietary fibres and water.
  • Dietary fibres are also known as roughage. They are mainly provided by plant products in our foods. Whole grains, pulses, potatoes, fresh fruits and vegetables are main sources.
  • Roughage does not have any nutritional value. It helps our body get rid of undigested food.
  • Water helps our body to absorb nutrients from food.
  • It also helps in throwing out some wastes from body as urine and sweat.

Balanced Diet

  • For growth and good health, our diet should have all the nutrients that our body needs, in right quantities. It should also contain a good amount of roughage and water. Such a diet is called a balanced diet.
  • Many useful proteins and considerable amount of minerals are lost if excess water is used during cooking and then thrown away.

Deficiency Diseases

  • A person may be getting enough food to eat, but sometimes the food may not contain a particular nutrient. If this continues over a long period of time, the person may suffer from its deficiency.
  • Diseases that occur due to lack of nutrients over a long period are called deficiency diseases. They can be prevented by taking a balanced diet.
  • Lack of proteins: stunted growth, swelling of face, discoloration of hair, skin diseases and diarrhoea.
  • Lack of carbohydrates & proteins: growth may stop completely.

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