Class 6 Science Chapter 2: Notes, Solutions & Guide CBSE

Class 6 Science: Chapter 2 - Components of Food

Chapter Summary

• Our daily food contains various components essential for our body's growth, repair, and energy supply. These vital components are known as **nutrients**.
• The main categories of nutrients found in our food are **Carbohydrates, Proteins, Fats, Vitamins, and Minerals**. Additionally, our food includes **dietary fibres (roughage)** and **water**.
• **Carbohydrates and Fats** are primarily responsible for providing energy to our body.
  • **Carbohydrates:** Exist mainly as starch and sugars. Common sources include rice, wheat, potatoes, sweet potatoes, sugar cane, maize, mango, melon, papaya, and jaggery.
  • **Fats:** Provide more energy per unit than carbohydrates. Sources can be plant-based (e.g., groundnut, nuts, sesame) or animal-based (e.g., milk, ghee, butter, cream, egg, meat, fish).
• **Proteins** are known as 'body-building foods' because they are crucial for the growth and repair of body tissues. Good sources include pulses, peas, beans, soya bean (plant-based), and milk, eggs, meat, fish, paneer (animal-based).
• **Vitamins** play a vital role in protecting our body from various diseases and maintaining the health of our eyes, bones, teeth, and gums. They are classified as Vitamin A, B complex, C, D, E, and K.
  • **Vitamin A:** Important for healthy skin and good eyesight. Found in papaya, carrots, mangoes, milk, and fish oil.
  • **Vitamin B complex:** A group of vitamins essential for various metabolic processes. Found in liver, whole grains, and rice.
  • **Vitamin C:** Helps the body fight against many diseases and keeps gums and teeth healthy. Rich sources include oranges, tomatoes, guavas, amla, lemons, and green chillies.
  • **Vitamin D:** Aids our body in absorbing calcium for strong bones and teeth. Our body can synthesize Vitamin D when exposed to sunlight. Also found in milk, butter, eggs, and fish.
• **Minerals** are required in small quantities for proper growth, development, and maintaining overall good health.
  • **Calcium:** Essential for strong bones and teeth. Found in milk and eggs.
  • **Phosphorus:** Also contributes to strong bones and teeth. Sources include milk, bananas, and fish.
  • **Iodine:** Necessary for the proper functioning of the thyroid gland. Found in seafood, iodised salt, and ginger.
  • **Iron:** Crucial for the formation of blood. Rich in spinach, apples, and liver.
• **Dietary fibres (Roughage)** are not digested by our body but are vital for the smooth movement of food through the digestive system and preventing constipation. Good sources include whole grains, pulses, potatoes, fresh fruits, and vegetables.
• **Water** constitutes a significant part of our body and has multiple functions. It helps in absorbing nutrients from food, regulating body temperature, and removing waste products from the body through urine and sweat. We obtain water from drinking water, milk, tea, and various food items.
• A **Balanced Diet** is a diet that provides all the necessary nutrients in appropriate quantities, along with sufficient roughage and water, to ensure proper functioning of the body. It emphasizes variety over relying on a single food type.
• **Deficiency diseases** are conditions that arise due to the prolonged absence or insufficient intake of one or more specific nutrients in the diet.
  • **Protein Deficiency:** Can lead to stunted growth, swelling of the face, discolouration of hair, skin diseases, and diarrhoea.
  • **Carbohydrate and Protein Deficiency:** Results in a complete halt of growth.
  • **Vitamin A Deficiency:** Causes loss of vision, including night blindness.
  • **Vitamin B1 (Thiamine) Deficiency:** Leads to Beri-beri, characterized by weak muscles and very low energy.
  • **Vitamin C Deficiency:** Causes Scurvy, symptoms include bleeding gums and longer time for wounds to heal.
  • **Vitamin D Deficiency:** Leads to Rickets, a condition where bones become soft and bent.
  • **Calcium Deficiency:** Results in weak bones and tooth decay.
  • **Iodine Deficiency:** Can cause Goitre (swollen glands in the neck) and mental disability in children.
  • **Iron Deficiency:** Leads to Anaemia, causing weakness and fatigue.
• Simple tests can be performed to detect the presence of starch, protein, and fat in food items.
  • **Test for Starch:** Add 2-3 drops of dilute iodine solution to the food sample. A blue-black colour indicates the presence of starch.
  • **Test for Protein:** Take a small quantity of food, add 10 drops of water, and shake. Then add 2 drops of copper sulphate solution and 10 drops of caustic soda solution. A violet colour confirms the presence of protein.
  • **Test for Fat:** Wrap the food item in a piece of paper and crush it. An oily patch on the paper indicates the presence of fat.

Questions and Answers

1. Name the major nutrients in our food.

Answer: The major nutrients in our food are Carbohydrates, Proteins, Fats, Vitamins, and Minerals. Our food also contains dietary fibres (roughage) and water.

2. Name the following:

a) The nutrients which mainly give energy to our body.

Answer: Carbohydrates and Fats.

b) The nutrients that are needed for the growth and maintenance of our body.

Answer: Proteins.

c) A vitamin required for maintaining good eyesight.

Answer: Vitamin A.

d) A mineral that is required for keeping our bones healthy.

Answer: Calcium.

3. Name two foods each rich in:

a) Fats

Answer: Butter, Groundnut.

b) Starch

Answer: Rice, Potato.

c) Dietary fibre

Answer: Whole grains, Fresh fruits.

d) Protein

Answer: Pulses, Eggs.

4. Tick (✓) the statements that are correct.

a) By eating rice alone, we can fulfil nutritional requirement of our body.

Answer: (X) Incorrect

b) Deficiency diseases can be prevented by eating a balanced diet.

Answer: (✓) Correct

c) Balanced diet for the body should contain a variety of food items.

Answer: (✓) Correct

d) Meat alone is sufficient to provide all nutrients to the body.

Answer: (X) Incorrect

5. Fill in the blanks:

a) Rickets is caused by deficiency of Vitamin D.

b) Deficiency of Vitamin B1 causes a disease known as beri-beri.

c) Deficiency of Vitamin C causes a disease known as scurvy.

d) Night blindness is caused due to deficiency of Vitamin A in our food.