CBSE Class 7 Science Advanced Biology Food and Food Preservation Short Answer Questions Set 01

Short Answer Questions

Question 1. What are nutrients? What are their different types?
Answer:
Nutrients are the substances that provide nourishment essential for the maintenance of life and for growth.
They are of two types: macronutrients (carbohydrates, proteins and fats) and micronutrients (vitamins and minerals).
In simple words: Nutrients feed the body; the big ones are macro and the small ones are micro.

Teacher's Note:
1. Classification depends on the amount needed.
2. Roughage and water are also needed in the diet.

Question 2. What is the difference between healthy and junk food?
Answer:
Healthy food contains all the necessary nutrients needed to keep good health and helps the body work properly, for example milk, fruits and vegetables.
Junk food has no specific nutrient content. It is tasty but contains unwanted oil, salt, etc. Eating too much of it increases body weight and can cause dietary disorders such as obesity, for example burger and pizza.
In simple words: Healthy food nourishes; junk food only tastes good and can harm.

Teacher's Note:
1. Give an example of each.
2. Mention obesity for junk food.

Question 3. What is food poisoning? What are its symptoms?
Answer:
Spoilt or expired food shows a change in appearance, taste, texture and smell, which means it is unsafe to eat. Eating it can cause food poisoning, which is caused by food-poisoning bacteria.
Symptoms may include nausea, vomiting, diarrhoea and stomach pain.
In simple words: Eating spoilt food can make you sick with vomiting and loose motions.

Teacher's Note:
1. Always smell and look at food before eating.
2. Bacteria in spoilt food cause the illness.

Question 4. What are the factors that cause food spoilage?
Answer:
1. Time: food may change in itself with time.
2. Microorganisms: bacteria, viruses and fungi attack uncovered food kept at room temperature.
3. Enzymes: enzymes present in food can spoil it, for example a banana turns from green to yellow to brown.
4. Environmental and chemical factors: food reacts with air and changes chemically.
5. Insects, rodents and pests physically damage the food.
In simple words: Time, microbes, enzymes, air and chemicals, and pests all spoil food.

Teacher's Note:
1. Write all five factors.
2. Give one example for each, such as the banana.

Question 5. What is food spoilage? What are the consequences of eating spoilt food?
Answer:
Food spoilage is the process by which food gets contaminated to the point at which it becomes unfit for consumption. Spoilt food shows a change in colour, gives out a foul smell and tastes bad.
Eating spoilt food can cause food poisoning with symptoms such as nausea, vomiting, diarrhoea and stomach pain.
In simple words: Spoilt food is unfit to eat and can make you ill.

Teacher's Note:
1. Mention colour, smell and taste.
2. Link it to food poisoning.

Question 6. A child was diagnosed with poor vision and loss of vision at night or darkness. What could be the disease and what could be the possible reasons for its onset?
Answer:
The disease is night blindness.
It is a deficiency disease caused by insufficient intake of vitamin A in the diet.
In simple words: Not enough vitamin A in food makes it hard to see in the dark.

Teacher's Note:
1. Carrots, milk and green leafy vegetables give vitamin A.
2. Night blindness is a vitamin A deficiency disease.

Question 7. People living in coastal areas generally do not suffer from goitre. Explain.
Answer:
The diet of people living in coastal areas mainly includes sea food, which is a rich source of iodine.
Goitre is caused by iodine deficiency, so these people usually do not suffer from it.
In simple words: Sea food gives plenty of iodine, which prevents goitre.

Teacher's Note:
1. Goitre means a swollen neck from the thyroid gland.
2. Iodised salt helps inland people.

Question 8. Excess intake of fats is harmful as it causes obesity. Would it be harmful to the body if there is excessive intake of proteins or vitamins?
Answer:
Yes. Excessive intake of proteins and vitamins is also harmful and may lead to other diseases.
The body needs every nutrient in the right amount, so a balanced diet is best.
In simple words: Too much of any nutrient can harm, not just fat.

Teacher's Note:
1. Balance matters more than quantity.
2. Over eating is as bad as under eating.

Question 9. Mrs. Sharma was worried about her daughter not eating properly even though her favourite dishes are made, and showed very small growth in last six months. Which nutrient deficiency may be there in the girl child?
Answer:
If the girl is not eating properly, she may be lacking in many essential nutrients.
Since the concern is about growth, the most likely deficiency is of proteins, which are the body-building foods.
In simple words: Poor growth points to a lack of protein.

Teacher's Note:
1. Proteins build muscles and body tissues.
2. Growth problems in children are linked to protein deficiency.