KSEEB Solutions for Class 8 Science Chapter 18 Food and Its Constituents

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Karnataka State Syllabus Class 8 Science Chapter 18 Food and Its Constituents

KSEEB Class 8 Science Food and Its Constituents Textbook Exercise Questions and Answers

I. Four alternatives are given to each of the following incomplete statements/questions. Choose the right answer.

Question 1.
The major metal present in bones is
(a) sodium
(b) iron
(c) calcium
(d) phosphorus
Answer:
(c) calcium

Question 2.
Children like to eat bakery items and chocolates. Elders advise them to eat vegetables also and not to keep aside curry leaves while eating food. This shows the importance of
(a) carbohydrates
(b) dietary fibres
(c) proteins
(d) lipids
Answer:
(b) dietary fibres

Question 3.
A green leaf that has fallen down from a plant is taken and kept in water for some time and then taken out, It is then dipped in spirit and iodine solution. The leaf turns bluish indicating the presence of value.
(a) starch
(b) oil
(c) protein
(d) fibre
Answer:
(a) starch

II. Fill in the blanks with suitable words:

Question:

1. Emulsion test is conducted to detect ______________
2. Fat-soluble vitamins are A, D, E and _________________
3. Amino acids contain the elements carbon, hydrogen, oxygen and ________________
4. The Haemoglobin is responsible for transportation of oxygen to the different parts of the body contains the metal _________________
5. Biuret solution contains sodium hydroxide and ___________________

Answer:

1. Fats and oils,
2. k,
3. nitrogen,
4. iron,
5. copper sulphate

III. Match the following:

Answer:
1. d,
2. f,
3. a,
4. b.

IV. Answer the following:

Question 1.
Why should we have variety in our diet?
Answer:
We do not all essential elements from just one type of food. Hence we should have variety in our diet to get all of the things we need for our body.

Question 2.
List four major sources of carbohydrates for the people in your region.
Answer:
The major sources of carbohydrates are cereals, sugar, aggery, potatoes, etc.

Question 3.
What food items Containing lipids do people in your region consume?
Answer:
Oils and fats are the main food items. Butter, cheese, cream, fatty meats are the other food items that give lipids.

Question 4.
List the nutritional importance of proteins.
Answer:

• Some proteins are involved in structural support and some others are involved in bodily movement.
• Proteins assist in building up a defence against germs.
• Enzymes which facilitate the biochemical reactions are also proteins.
• Hormones are also proteins.
• Hemoglobin which is present in the blood is protein.
• Proteins like Keratin and Collagen which are fibrous and tough, provide support to tendons and ligaments.

Question 5.
Why do some people suffer from nutritional deficiencies despite having enough food?
Answer:
Despite having enough food some people suffer from nutritional deficiencies since they do not take a completely balanced diet which provides all the nutrients to our body in the right proportion.

Question 6.
Explain the importance of water in our diet.
Answer:
Importance of water is,

1. Water constitutes about 55-75 percent of our body mass.
2. It helps to maintain the health of every cell in the body
3. It keeps the blood thin enough to plow through the blood.
4. It helps to eliminate the water and excess materials
5. Water regulates body temperature through sweating.
6. Water helps digestion and prevents constipation.
7. It helps to carry nutrients and oxygen to the cells.

Question 7.
A beaker contains a thick liquid, How do you test whether it is a lipid?
Answer:
Take 5 ml of the give sample in a test tube add small amount of ethyl alcohol to it. Shake well. Heat the test tube carefully on water bath, when the sample dissolves in alcohol filter or dilute until you get a clear liquid take a small quantity of tap water in another test tube, pour the solution prepared above gently into the test tube. If a whitish suspension is formed then the given sample is a lipid.

Question 8.
What is the function of calcium in our bodies?
Answer:

• Calcium helps to build bones and teeth.
• It helps in the proper functioning of muscles, heart and nerves, relieves pain and cramps.
• It also helps in the clotting of blood.

Question 9.
List all the major classes if ingredients that should be present in a balanced diet.
Answer:
Balanced diet should contain a variety of nutrients like carbohydrates, proteins, fats, vitamins minerals and dietary fiber in right quantity according to age, sex, size of the body, and activity to maintain normal health.

Question 10.
Make a list of food items that are rich in dietary fibres.
Answer:
The food, which is rich in dietary fiber, are fruits, vegetables and greens, cabbage, peas, carrot turnips, and edible skins like apple guava, pear cereals, and pulses are some of the food items which have high dietary fiber.

Think

Question 1.
Why do children both in rich and poor families suffer from nutritional deficiencies? What are your suggestions to improve the situation?
Answer:
Young children in poor families suffer from nutritional deficiencies due to a lack of proper food. Children raised in a poor family have deprived of a balanced diet or even a meal once a day. Young children in rich families suffer from nutritional deficiency because of having fast food which does not have nutritional value.

We can suggest then to have food containing, carbohydrates, proteins, vitamins, iron, calcium-rich food and those who can’t afford it can help those people through social organizations.

Question 2.
How does lack of nutrition affect your activities, studies and personality? How can you prevent it?
Answer:
When there is a lack of nutrition say for example lack of calcium, magnesium and zinc there are tendencies of being hyperkinetic where, a person is unable to sit for more than few minutes and bones will become weak. Lack of proper nutrition affects our activities, studies and personality. This can be prevented by having a balanced diet.

Question 3.
What dietary charges at your home will improve the nutritional status of your family members?
Answer:
Good nutrition is one of the major key’s to a healthy life. We can improve our family health by resorting to a balanced diet. We should eat food that contains vitamins and minerals. This includes fruits, vegetables, whole grains, dairy products and some such sources of protein.

KSEEB Class 8 Science Food and Its Constituents Additional Questions and Answers

I. Answer the following

Question 1.
What is food?
Answer:
Food can be defined as a substance ( which nourishes the body.

Question 2.
Why do we have food? Mention the functions of food.
Answer:
Food promotes growth, supplies energy, furnishes materials for repair of body parts. It is also necessary for all metabolic processes and to maintain body temperature constant. Hence we should have food.

Question 3.
Mention the major constituents of food.
Answer:
Carbohydrates, lipids, proteins, vitamins, minerals water and fibres are the main constituents of food.

Question 4.
Mention the three groups of the constituents of food on the basis of their function.
Answer:

• Energy releasing food:- Carbohydrates and lipids
• Bodybuilding food Proteins
• Protective food Vitamins and minerals

Question 5.
What are carbohydrates?
Answer:
Carbohydrates are naturally occurring macronutrients which form a major component of living organisms. They include sugars, starch and cellulose. These are the compounds made of carbon, hydrogen and oxygen.

Question 6.
Write the Nutritional significance of carbohydrates.
Answer:
Carbohydrates on digestion turn into glucose. Glucose gets into the blood.
Carbohydrates help in the regulation of sugar in the bloodstream. Thus it acts as a shield and protects muscles. Fibres present in the carbohydrates such as cellulose, keep body movements smooth. It is oxidized in the mitochondria to release energy during cellular respiration and the energy is used by cells for various metabolic activities.

Question 7.
Mention the nutritional disorders due to carbohydrates.
Answer:
Any inadequacy or excess of glucose might lead to adverse effects.
Insufficient supply of glucose may lead to tiredness, weakness and lack of concentration. Excess of glucose can lead to obesity.

Question 8.
What are lipids?
Answer:
Lipids are macromolecules which are generally stored in the body. Lipids include fats, oils, waxes and steroids. Lipids serve as fat reserves.

Question 9.
Mention the nutritional significance of lipids.
Answer:
Lipids play a very important role in our body. They help in brain functions, smooth movements of joints, clotting of blood and energy production. Some lipids help to bring down inflammation within the body and lubricate the joints.

• Fats help the body to absorb and to move the vitamin A D E and K.
• Cell membranes which contain lipids lubricate the ceils and this lubrication serves as a protective barrier which controls the movement of materials.
• Lipids store more energy and hence help in energy production.
• Lipids act as messengers within our bodies.
• Fats also help to maintain healthy skin and hair.

Question 10.
What are proteins?
Answer:
Proteins are one of the macronutrients which are typically constructed from a set drawn from 20 simple compounds called amino acids.

Question 11.
What is an amino acid?
Answer:
Amino acid is the simplest molecule from which protein is formed Amino acid molecule consists of atoms of Carbon (C), hydrogen (H), a Carboxyl group (-COOH) and an amino group (-NH₂)

Question 12.
What are vitamins? Which are the two types?
Answer:
Vitamins are a group of organic compounds which are vital for normal growth, development, and maintenance of the body and are only required in very small quantities.

The two types of vitamins are:

• Water-soluble — Vitamins B and C
• Fat-soluble — Vitamins A, D, K, & E

Question 13.
What do you mean by pro vitamins?
Answer:
We need certain substances like beta -carotene and folio which get converted into vitamins in our body These are called pro-vitamins.

Question 14.
What are minerals?
Answer:
Minerals are the inorganic substances required in small quantities for growth and normal functioning of the body. The important minerals which should be there in the diet are calcium, iron, copper, magnesium, zinc, and iodine.

Question 15.
What is the function of Iodine in our bodies?
Answer:
Iodine helps in the functioning of the thyroid gland. It prevents goiter. It helps to burn fat, converts beta-Carotene into vitamin A. It regulates energy production in our body and maintains hair, nail skin, and teeth.

Question 16.
Write the function of zinc in our diet.
Answer:
Zinc in our diet helps to reduce cholesterol deposits, helps in making enzymes and insulin, supports metabolism of carbohydrates, facilitates the proper functioning of prostate glands.

Question 17.
Write the function of potassium in our diet.
Answer:
Potassium helps to regulate the fluid balance in our body. It also help in the functioning of nerves and muscles.

Question 18.
Mention the functions of roughage.
Answer:

• Dietary fibre provides volume to the food, and this facilitates the easy movement of materials in the alimentary canal.
• Roughages have the ability to absorb water.
• They combine with intestinal wastes making them bulky.
• This expands the intestinal lumen and stimulates the movement of waste in the gastrointestinal tract.
• Thus it facilitates the elimination of intestinal wastes.

Question 19.
How does constipation occur?
Answer:
When the intestinal materials have little bulk, the movement of materials in the large intestine and bowel movement becomes difficult. This is because too much of water is absorbed from undigested food. Hence, the materials become relatively dry and hard. This results in constipation.

Question 20.
What do you mean by O R S?
Answer:
O R S is the short form of Oral Rehydration Solution, which is given to the patients suffering form cholera, acute diarrhea etc. It is prepared by adding 2 spoons of sugar, % spoon of common salt, and a % spoon of sodium bicarbonate in one litre of boiled and cooled water.

Question 21.
Write the test for glucose.
Answer:
To test the presence of glucose, add about 5-6 drops of Benedict’s reagent to 5 ml of a sample taken in a test tube. Heat for about two minutes if the colour of the precipitate changes to yellow, orange, or brick red, it shows the amount of glucose present.

Question 22.
Write the test for starch.
Answer:
Take a small quantity of the given foodstuff in a dish. Add 2-3 drops of iodine solution. The appearance of a blue-black colour indicates the presence of starch.

Question 23.
Write a simple test for protein.
Answer:
Take about 5 ml of the sample in a test tube. Add 5 -6 drops of Biuret solution. Do not heat Wait for a while. The colour changes from blue to pink indicating the presence of protein in the given sample.

Give scientific reasons for the following :

Question 1.
We must take carbohydrates in moderate quantity:
Answer:
Excess of glucose can add to our weight. Hence we must take carbohydrates in moderate quantity.

Question 2.
Athletes and sportspeople after an intense activity eat glucose:
Answer:
Persons with intense activity need more carbohydrates to release energy. Glucose is the simplest form of carbohydrate which is easily absorbable.

Question 3.
Fibres do not help in providing energy or building tissues but have to be an essential part of our food:
Answer:
Fibres help the normal functioning of the digestive system and keep the bowel movement smooth, avoiding constipation. Therefore fibres should be an essential part of our food.

Question 4.
Doctors usually do not recommend butter, cheese, cream etc. for some people.
Answer:
The fat that comes from animal sources is not good for health as plant sources.

Question 5.
Dr. Denis Burkitt was nicknamed as the Fibre man:
Answer:
Dr. Denis Burkitt made a hypothesis that dietary fibre can prevent certain diseases. Therefore he was nicknamed as ‘Fibre man’.

Question 6.
We should not allow dehydrating our body:
Answer:
If the dehydration is acute urination stops, the kidneys fail and the body cannot remove toxic waste products. In extreme cases, this may result in death.

II. Fill in the blanks:-

Question 1.
Water does not provide any _____________.
Answer:
nutrients,

Question 2.
Food containing nourishing substances are called _____________.
Answer:
nutrients,

Question 3.
The simplest form of carbohydrates _____________.
Answer:
glucose,

Question 4.
The excessive collection of fats in the body may result in _____________.
Answer:
obesity,

Question 5.
Fibres present in the carbohydrates are called _____________.
Answer:
cellulose,

Question 6.
Lipids are _____________ in water.
Answer:
insoluble,

Question 7.
The simplest form of protein is _____________.
Answer:
amino acid,

Question 8.
The enzyme which breaks the protein in our stomach is _____________.
Answer:
pepsin,

Question 9.
The enzyme which breaks down the sugar in milk is _____________.
Answer:
lactase,

Question 10.
Messenger proteins are called as _____________.
Answer:
hormones,

Question 11.
The protein which helps in the transport of oxygen in our body is _____________.
Answer:
hemoglobin,

Question 12.
Beta Carotene, folic acid etc. are commonly called as _____________.
Answer:
pro-vitamins,

Question 13.
Dr. Denis Burkitt was nicknamed as the _____________.
Answer:
Fibre man,

Question 14.
Diarrhoea, vomiting or both are the common causes of _____________.
Answer:
dehydration,

Question 15.
The Indian physician who treated acute diarrhea with rice water and coconut juice was _____________.
Answer:
Sushruta,

Question 16.
The first Indian doctor who prescribed O RS for cholera patients was _____________.
Answer:
Dr. Hemendra Nath Chatterjee,

Question 17.
An intake of _____________ glasses of water a day is recommended for maintaining good health.
Answer:
6-8

Question 18.
Benedict’s solution is in _____________ colour
Answer:
blue,

Question 19.
A solution of copper sulphate, sodium hydroxide and tartaric acid is known as _____________ reagent.
Answer:
Benedict’s,

Question 20.
Blue-black colour of food substance with iodine indicates the presence of _____________.
Answer:
starch,

Question 21.
A bluish solution of sodium hydroxide and a small amount of copper sulphate is known as _____________.
Answer:
Biuret solution,

Question 22.
A mixture of two liquids which do not mix with one another is called as _____________.
Answer:
Emulsion,

Question 23.
The emulsion is a _____________ of one liquid in another.
Answer:
suspension,

Question 24.
A vitamin which assists in protein synthesis is vit _____________.
Answer:
K,

Question 25.
A vitamin which lowers the blood cholesterol is vit _____________.
Answer:
E,

Question 26.
A vitamin which promotes the growth of bones and teeth is vitamin _____________.
Answer:
D,

Question 27.
A vitamin which prevents internal bleeding is vit _____________.
Answer:
C,

Question 28.
A vitamin which helps in preventing infections is vit _____________.
Answer:
C,

Question 29.
A vitamin which promotes the utilization of protein, fats and carbohydrates is vit _____________.
Answer:
B₁₂

Question 30.
A vitamin which helps in converting sugar and starch into energy is vit _____________.
Answer:
B₁

Question 31.
A vitamin which improves the night vision is vit _____________.
Answer:
A,

Question 32.
A vitamin which is essential for the formation of red blood cells is vit _____________.
Answer:
B₁₂

Question 33.
A vitamin which is involved in amino acid metabolism is vit _____________.
Answer:
B₆

Question 34.
A vitamin which help in releasing energy to the body cells is vit _____________.
Answer:
B₂,

Question 35.
The vitamin which synthesized by the body itself, by exposure to the sunlight is vit _____________.
Answer:
D.

III. Match the following:

A – B
1) Night Blindness – a) Vitamin B₁
2) Rickets – b) Vitamin B₆
3) Beri-beri – c) Vitamin B₁₂
4) 3 D Symptoms – d) Vitamin A
5) Acute anaemia – e) Vitamin C
6) Scurvy – f) Vitamin D
Answer:
1. d,
2. f,
3. a,
4. b,
5. c,
6. e

IV. Choose the best alternative:
Question 1.
Beta – Carotene gets converted into our body.
(a) Vit. A
(b) Vit. B
(c) Vit C
(d) Vit D
Answer:
(a) Vit. A

Question 2.
Pepsin converts
(a) Carbohydrates to glucose
(b) Fats to fatty acids
(c) Protein to polypeptides
(d) Fats to glucose
Answer:
(c) Protein to polypeptides

Question 3.
Lactase converts
(a) Carbohydrates to glucose
(b) Cane sugar to glucose
(c) maltose to glucose
(d) milk sugar to glucose
Answer:
(d) milk sugar to glucose

4. Fats are soluble in
(a) water
(b) blood
(c) alcohol
(d) lymph
Answer:
(c) alcohol

Question 5.
The carbohydrate that cannot be digested in our body is
(a) Glucose
(b) Lactose
(c) Maltose
(d) Cellulose
Answer:
(d) Cellulose

Question 6.
One which does not contain protein is
(a) Nucleic acid
(b) water
(c) Antibody
(d) insulin
Answer:
(b) water

Question 7.
Carbon, hydrogen, oxygen, and nitrogen are the contents which generally form
(a) Protein
(b) Fat
(c) Glycogen
(d) Carbohydrates
Answer:
(a) Protein

Question 8.
Iodine is used to test
(a) sugar
(b) salt
(c) starch
(d) fat
Answer:
(c) starch

Question 9.
The two major energy-releasing nutrient are
(a) Protein and fats
(b) Carbohydrates and lipids
(c) Lipids and Vitamins
(d) Proteins and Carbohydrates
Answer:
(b) Carbohydrates and lipids

Question 10.
Dietary lipids are
(a) fats and oils
(b) fatty acids and glycerol
(c) wax and steroids
(d) fats and steroids
Answer:
(a) fats and oils

Question 11.
The end product of carbohydrate after digestion is
(a) Glucose
(b) amino acid
(c) Fatty acid
(d) glycerol
Answer:
(a) Glucose

Question 12.
The fat-soluble vitamins are
(a) A,B, C,D
(b) A, B, E, K
(c) A, D, E, K
(d) A,B,C, K
Answer:
(c) A, D, E, K

Question 13.
The mineral essential for the clotting of blood is.
(a) Sodium
(b) Phosphorus
(c) Iron
(d) Calcium
Answer:
(d) Calcium

Question 14.
The mineral present in haemoglobin is
(a) Iodine
(b) Calcium
(c) Iron
(d) Sodium
Answer:
(c) Iron

Question 15.
The constituent of the food which has the ability to absorb water is
(a) Carbohydrates
(b) Fats
(c) Proteins
(d) Roughage
Answer:
(d) Roughage

Question 16.
The mineral essential for the synthesis of thyroxine is
(a) Iodine
(b) Iron
(c) Sodium
(d) Potassium
Answer:
(a) Iodine

Question 17.
The minerals needed for teeth and bones are
(a) Calcium and Sodium
(b) Calcium and Phosphorus
(c) Calcium and Potassium
(d) Calcium and Iron
Answer:
(b) Calcium and Phosphorus

Question 18.
The vitamin needed for the production of RBC and nucleoprotein synthesis is
(a) Vit. B₂
(b) Vit B₂
(c) Vit B₃
(d) Folic acid
Answer:
(d) Folic acid

Question 19. The food which contains iodine is
(a) leafy vegetables
(b) cereals
(c) seafood
(d) fruits
Answer:
(c) seafood

Question 20.
The food in which vitamin C is present is
(a) Citrus fruits
(b) Milk
(c) Egg
(d) Soya beans
Answer:
(a) Citrus fruits

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