NCERT Solutions for Class 6 Science Chapter 2 Components of Food | KalviGavani

Components of Food: NCERT Exercise Solutions

How to Use This Page

This page provides complete NCERT exercise solutions for Class 6 Science Chapter 2 — Components of Food. Read the chapter in your textbook first, attempt each question on your own, and then compare your answers with the solutions below. The explanations are detailed and follow the NCERT style, with real-world examples to strengthen your understanding.

Tips for best results:

• Memorise the key nutrients and their functions from the Key Concepts table.
• Practise the food tests (starch, protein, fat) — these are frequently asked in exams.
• Learn the deficiency diseases and their associated nutrients thoroughly.
• Use the Exam Checklist to verify you have covered every important topic before the test.

Key Concepts (Quick Recap)

Intext Questions and Answers

Question 1. Name the major nutrients in our food.

1. Carbohydrates — provide energy 2. Fats — provide energy (more than carbohydrates) and insulate the body 3. Proteins — help in growth and repair of body tissues 4. Vitamins — protect the body from diseases and maintain health (Vitamins A, B, C, D, E, K) 5. Minerals — required for various bodily functions (calcium, iron, iodine, phosphorus, etc.)

In addition to these five nutrients, roughage (dietary fibre) and water are also essential components of food.

Question 2. Name the following:

(a) A nutrient needed for the growth and repair of our body. (b) The nutrients mainly giving energy to our body. (c) A nutrient needed in very small quantities for proper growth and good health. (d) A nutrient that protects our body from diseases.

(a) Protein — Proteins are the body-building nutrients. They are needed for the growth of the body and for repairing worn-out tissues. Rich sources: pulses, eggs, meat, fish, milk.

(b) Carbohydrates and Fats — Both are energy-giving nutrients. Carbohydrates provide quick energy (sources: rice, wheat, sugar, potato). Fats provide more energy per gram than carbohydrates (sources: butter, ghee, oil, nuts).

(c) Vitamins and Minerals — These are called micronutrients because they are needed in very small quantities. However, their deficiency can cause serious diseases.

(d) Vitamins — Vitamins protect the body from diseases and infections. For example, Vitamin C boosts immunity, and Vitamin A keeps eyes healthy.

Question 3. Name two foods that are rich in: (a) Fats (b) Starch (c) Dietary fibre (d) Protein

(a) Fats-rich foods: Butter, ghee, cheese, oil, nuts (almond, groundnut), coconut

(b) Starch-rich foods: Rice, wheat (chapati), potato, corn, bread

(c) Dietary fibre-rich foods: Whole grains (wheat bran, oats), fresh fruits (apple, guava), green leafy vegetables (spinach), beans, lentils

(d) Protein-rich foods: Eggs, meat, fish, pulses (moong, chana, arhar), milk, paneer, soyabean

Question 4. Tick (√) the statements that are correct:

(a) By eating rice alone, we can fulfil the nutritional requirement of our body. (×) (b) Deficiency diseases can be prevented by eating a balanced diet. (√) (c) Balanced diet for the body should contain a variety of food items. (√) (d) Meat alone is sufficient to provide all nutrients to the body. (×)

(a) Incorrect (×) — Rice alone cannot provide all nutrients. Rice mainly provides carbohydrates. The body also needs proteins, fats, vitamins, minerals, and roughage.

(b) Correct (√) — A balanced diet contains all nutrients in proper proportions, which prevents deficiency diseases.

(c) Correct (√) — A balanced diet must include a variety of food items such as cereals, pulses, vegetables, fruits, milk, and fats to provide all nutrients.

(d) Incorrect (×) — Meat is rich in protein and fat but lacks carbohydrates, many vitamins (like Vitamin C), minerals, and roughage. A balanced diet needs variety.

Question 5. Fill in the blanks:

(a) ———- is caused by deficiency of Vitamin D. (b) Deficiency of ———- causes a disease known as beriberi. (c) Deficiency of Vitamin C causes ———-. (d) Night blindness is caused due to deficiency of ———-.

(a) Rickets is caused by deficiency of Vitamin D. (Note: Rickets is also caused by deficiency of calcium.)

(b) Deficiency of Vitamin B1 (thiamine) causes a disease known as beriberi.

(c) Deficiency of Vitamin C causes scurvy. (Bleeding gums and loose teeth are common symptoms.)

(d) Night blindness is caused due to deficiency of Vitamin A. (The person cannot see clearly in dim light.)

Question 6. Can you name some food items that are rich in:

(a) Carbohydrates — ———-, ———- (b) Proteins — ———-, ———- (c) Fats — ———-, ———- (d) Vitamin C — ———-, ———- (e) Iron — ———-, ———- (f) Calcium — ———-, ———-

(a) Carbohydrates — Rice, wheat, potato, sugar, maize, banana

(b) Proteins — Eggs, pulses (moong, chana), meat, fish, milk, soyabean, paneer

(c) Fats — Butter, ghee, oil (mustard, sunflower), nuts, coconut, cheese

(d) Vitamin C — Orange, lemon, amla (Indian gooseberry), guava, tomato, green chilli

(e) Iron — Spinach (palak), jaggery (gur), liver, eggs, dates, green leafy vegetables

(f) Calcium — Milk, curd, cheese, ragi, eggs, fish, green leafy vegetables

Question 7. What is the function of roughage in our body?

1. Adds bulk to the food — Fibre absorbs water and swells up, giving volume to the waste material in the intestines. 2. Helps in bowel movement — Fibre stimulates the muscles of the intestines, helping food move smoothly through the digestive tract. 3. Prevents constipation — By making the stool soft and bulky, roughage helps in easy elimination of waste. 4. Removes toxins — Fibre helps sweep waste and harmful substances through the intestines.

Sources of roughage: Whole grains (wheat bran, oats), fresh fruits (apple, guava, banana), raw vegetables (carrot, cucumber), green leafy vegetables (spinach), and beans.

Question 8. Why is water important for our body?

1. Transport — Water carries digested food, oxygen, and other nutrients to all parts of the body through blood. 2. Waste removal — Water helps remove waste products from the body through urine and sweat. 3. Temperature regulation — Sweating (which is mostly water) helps cool the body in hot weather. 4. Chemical reactions — Most chemical reactions in the body take place in the presence of water. 5. Digestion — Water helps in the digestion of food and absorption of nutrients. 6. Lubrication — Water acts as a lubricant in joints and keeps the skin moist.

We should drink 6-8 glasses of water every day to stay healthy.

Exercise Questions and Answers

Question 1. What are nutrients? Name the main nutrients.

The main nutrients are: 1. Carbohydrates — energy-giving 2. Fats — energy-giving and insulation 3. Proteins — body-building 4. Vitamins — protective 5. Minerals — protective and structural

In addition, roughage (dietary fibre) and water are also essential components of food, though they are not classified as nutrients in the strictest sense.

Question 2. Why does our body need nutritious food?

1. Energy — Carbohydrates and fats provide the energy needed for all activities — walking, running, studying, and even sleeping. 2. Growth — Proteins are required for the growth of the body, especially in children and teenagers. 3. Repair — Proteins help repair damaged tissues and heal wounds. 4. Protection — Vitamins and minerals protect the body from diseases and infections. 5. Maintenance — Nutrients maintain the proper functioning of all organs and systems. 6. Bones and teeth — Calcium and phosphorus make bones and teeth strong. 7. Blood formation — Iron is needed to make haemoglobin in red blood cells, which carries oxygen.

Eating a variety of nutritious foods (a balanced diet) ensures that the body receives all the nutrients it needs.

Question 3. What is a balanced diet? Is it the same for everyone?

No, a balanced diet is not the same for everyone. It varies depending on:

1. Age — Growing children need more proteins and calcium. Elderly people need less fat and more fibre. 2. Gender — Adolescent girls and women need more iron to compensate for blood loss during menstruation. 3. Activity level — A labourer who does heavy physical work needs more carbohydrates and fats for energy compared to a person who sits at a desk all day. 4. Health condition — A sick person or a recovering patient may need more proteins and vitamins. A person with diabetes needs to limit sugar and carbohydrates. 5. Climate — People in cold climates may need more fats, while people in hot climates may need more water and electrolytes.

Question 4. Name the deficiency diseases caused by the lack of: (a) Vitamin A (b) Vitamin B1 (c) Vitamin C (d) Vitamin D (e) Iron (f) Iodine

Question 5. Describe tests to detect the presence of: (a) Starch (b) Protein (c) Fat

(a) Test for Starch:

1. Take a small quantity of the food item (e.g., potato, rice) in a test tube. 2. Add a few drops of dilute iodine solution to it. 3. Observe the colour change.

• If the colour changes to blue-black, starch is present.
• If there is no colour change, starch is absent.

(b) Test for Protein:

1. Take a small quantity of the food item (e.g., egg white, dal water) in a test tube. 2. Add 2 mL of copper sulphate solution. 3. Add 2 mL of caustic soda (sodium hydroxide) solution. 4. Shake the test tube gently and observe.

• If the colour changes to violet/purple, protein is present.
• If there is no colour change, protein is absent.

(c) Test for Fat:

1. Take a small quantity of the food item (e.g., butter, groundnut). 2. Rub it on a piece of white filter paper. 3. Observe the paper.

• If an oily translucent spot appears on the paper (which lets light pass through), fat is present.
• If the paper remains clean, fat is absent.

Alternative test for fat: Wrap the food item in a piece of newspaper and crush it. If the newspaper develops an oily stain, fat is present.

Question 6. Choose the correct option:

Which of the following is a deficiency disease caused by lack of Vitamin C?

(A) Beriberi (B) Scurvy ✓ (C) Rickets (D) Goitre

Scurvy is caused by deficiency of Vitamin C. Its symptoms include bleeding gums, loose teeth, and slow wound healing. Beriberi is caused by deficiency of Vitamin B1; rickets by deficiency of Vitamin D; goitre by deficiency of iodine.

Question 7. Choose the correct option:

Which nutrient is mainly required for growth and repair of the body?

(A) Carbohydrates (B) Fats (C) Proteins ✓ (D) Vitamins

Proteins are body-building nutrients. They are required for the growth of new tissues and for repairing worn-out or damaged tissues in the body. Carbohydrates and fats provide energy; vitamins protect from diseases.

Question 8. Choose the correct option:

Roughage helps in:

(A) Providing energy (B) Building muscles (C) Bowel movement ✓ (D) Protecting from diseases

Roughage (dietary fibre) adds bulk to the food and helps in the smooth movement of waste through the intestines. It prevents constipation. Energy comes from carbohydrates and fats; muscle building from proteins; disease protection from vitamins and minerals.

Question 9. Explain why a doctor advises a patient with weak bones to include more milk and eggs in the diet.

Milk is an excellent source of both calcium and Vitamin D (milk is often fortified with Vitamin D). Eggs contain Vitamin D (in the yolk) and some calcium. By including milk and eggs in the diet, the patient can increase the intake of these nutrients, which will help strengthen the bones over time.

Additionally, the doctor may advise the patient to get some sunlight exposure because the skin produces Vitamin D when exposed to sunlight.

Question 10. Why should we not eat the same type of food every day?

1. No single food contains all nutrients. Different foods provide different nutrients. Rice gives carbohydrates but not enough protein or vitamins. Milk gives calcium and protein but not enough iron or Vitamin C. 2. Risk of deficiency diseases. If we eat only one type of food, we may miss certain nutrients, leading to deficiency diseases. For example, eating only rice may lead to protein or vitamin deficiency. 3. Balanced nutrition requires variety. A balanced diet must include cereals, pulses, vegetables, fruits, milk, and fats to provide all nutrients in proper proportions. 4. Different nutrients have different functions. The body needs carbohydrates for energy, proteins for growth, fats for insulation, vitamins for protection, and minerals for various functions. Only a varied diet can supply all of these. 5. Taste and appetite. Eating the same food every day can be boring and may reduce appetite, leading to less food intake overall.

Multiple Choice Questions (MCQ) for Practice

Q1. Which nutrient provides the maximum energy per gram?

(A) Carbohydrates (B) Proteins (C) Fats ✓ (D) Vitamins

Q2. Which vitamin is produced by the skin when exposed to sunlight?

(A) Vitamin A (B) Vitamin B (C) Vitamin C (D) Vitamin D ✓

Q3. Goitre is caused by deficiency of:

(A) Iron (B) Iodine ✓ (C) Calcium (D) Vitamin A

Q4. Which of the following food items is richest in protein?

(A) Rice (B) Butter (C) Soyabean ✓ (D) Orange

Q5. The iodine test is used to detect the presence of:

(A) Protein (B) Fat (C) Starch ✓ (D) Vitamin C

Common Mistakes to Avoid

1. Confusing the food tests: Students often mix up which test detects which nutrient. Remember: Iodine test → Starch (blue-black colour), Copper sulphate + caustic soda → Protein (violet colour), Filter paper/rubbing test → Fat (oily translucent stain). Write these on a flashcard and memorise them.

2. Mixing up deficiency diseases and their nutrients: The most common mistake is confusing which deficiency disease is caused by which nutrient. Create a mnemonic: "ABC DIRT" — A-night blindness, B-beriberi, C-scurvy, D-rickets, I-goitre (Iodine), R-anaemia (Red blood cells/Iron), T-noting that all are preventable with a balanced diet.

3. Thinking fats are always bad: Fats are essential nutrients. They provide energy (more than carbohydrates), insulate the body against cold, and protect internal organs. Only excess fat intake is harmful. Do not say "fats should be avoided."

4. Forgetting roughage and water as essential components: Roughage and water are not nutrients in the strict sense, but they are essential components of a balanced diet. Roughage helps in digestion and bowel movement; water is needed for all body processes. Never omit them when listing components of food.

5. Confusing anaemia with goitre: Anaemia is caused by iron deficiency (affects blood/haemoglobin), while goitre is caused by iodine deficiency (affects thyroid gland). These are entirely different conditions with different causes and symptoms.

Exam Checklist

Before your exam, make sure you can answer "Yes" to each of the following:

• [ ] I can name all five major nutrients (carbohydrates, fats, proteins, vitamins, minerals) and state their functions.
• [ ] I can list at least three food sources for each nutrient.
• [ ] I can describe the three food tests (starch, protein, fat) with the correct reagents and colour changes.
• [ ] I can match each deficiency disease with its nutrient: night blindness (Vit A), beriberi (Vit B1), scurvy (Vit C), rickets (Vit D), goitre (iodine), anaemia (iron).
• [ ] I can define a balanced diet and explain why it is different for different people.
• [ ] I can explain the importance of roughage and water in the diet.
• [ ] I can identify which nutrient is being tested when given a description of a food test procedure.
• [ ] I can give at least two examples of food items rich in each nutrient category.