NCERT Class 10 Chapter 7 Life Process CBSE Board Sample Problems Long Answer

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Question

(a) Draw a diagram of human alimentary canal and label on it: Oesophagus. Buccal cavity, stomach, small intestine, large intestine (colon).

(b) Explain the statement, ‘Bile does not contain any enzyme but it is essential for digestion’.

Solution

(a)

Human alimentary canal and label

Human Alimentary Canal and Label

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(b) Bile does not contain any enzyme, but it plays an important role in digestion because:

(i) The bile salts emulsify fat by acting on large fat globules to break them into smaller globules. This increases the efficiency of pancreatic enzymes.

(ii) The food entering the small intestine is acidic. It is made alkaline by the action of bile juice so as to facilitate the action of pancreatic enzymes.

Question

i) Elucidate the process of double circulatory system with the help of a diagram.

ii) Write one function each of the following components of the transport system in human beings:

a) Blood vessels

b) Blood platelets

c) Lymph

d) Heart

Solution

The oxygenated blood from the lungs returns to the heart, which is pumped again into different parts of the body by the heart. Thus, the blood passes twice through the heart making one complete round through the body. This is called double circulation.

The oxygenated blood from the lungs returns to the heart

The Oxygenated Blood from the Lungs Returns to the Heart

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ii)

(a) Blood Vessels: Transport of blood.

(b) Blood Platelets: Clotting of blood.

(c) Lymph: Carries digested fats.

(d) Heart: Helps to circulate blood in the whole body by acting as a pump.

Question

How does aerobic respiration differ from anaerobic respiration?

Solution

Aerobic Respiration Anaerobic Respiration

Aerobic Respiration

Anaerobic Respiration

1. Aerobic Respiration takes place in the presence of oxygen.

1. Anaerobic Respiration takes place in the absence of oxygen.

2. Complete breakdown of food occurs in it.

2. Incomplete breakdown of food occurs in it.

3. The end products are carbon dioxide () and water (

3. The end products are ethyl alcohol () and carbon dioxide or lactic acid.

4. It produces a considerable amount of energy due to complete oxidation of food molecules.

4. Much less energy is produced due to incomplete oxidation of food.

Question

Differentiate between blood and lymph.

Solution

Differentiate between blood and lymph

Blood

Lymph

1. Red in colour.

1. Colourless.

2. Red blood corpuscles are present.

2. Red blood corpuscles are absent.

3. Lymphocytes are present.

3. Lymphocytes are present more in number than the blood.

4. Nutritive substances are more.

4. Nutritive substances are less in amount.

5. Oxygen is more.

5. Oxygen is relatively less.

6. Metabolic wastes and are in normal amount.

6. Both are more than blood.

7. Soluble proteins are more than insoluble proteins,

7. Insoluble proteins are more than soluble proteins.

8. Fibrinogen in large amount.

8. Fibrinogen in less amount.

Question

Describe the process of digestion in man.

Solution

  • Food is broken down by teeth, rolled by tongue and acted upon by saliva to form a paste.

  • This food reaches the stomach where gastric juice from Gastri glands is secreted.

  • Gastri juice contains — HCI, Pepsin and mucus.

  • Pepsin digests proteins, HCI kills germs.

  • From stomach semi digested food reaches the small intestine where it mixes with bile juice from liver and pancreatic juice from pancreas.

Pancreatic juice has -

  • Trypsin which completely digests protein into peptones and peptides.

  • Amylase digests starch.

  • Lipase digests fats into fatty acids and glycerol.

  • Bile emulsifies fat and changes the medium of food from acidic to alkaline.

  • Finally digested food is absorbed by the walls of the small intestines lines by villi.

Question

Draw a sectional view of the human heart and label on it. Aorta, right ventricle, pulmonaryvein, pulmonary artery

b) State the functions of:

i) Blood

ii) Lymph.

Solution

The human heart and label

The Human Heart and Label

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Ans b i) Blood transports nutrients, oxygen,, urea, hormones etc.

ii) WBC kills germs.

Lymph - drains excess fluid from extra cellular space back into blood.

Question

Draw a neat labeled diagram of excretory system of human beings.

Solution

system of human beings

System of Human Beings

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Question

Give an experiment to prove that is necessary for photosynthesis.

Solution

  • Two similar potted plants which are destarched are kept in sunlight covered with a glass jar. (1)

  • Inside one jar ‘A’ a plate containing KOH is kept. (1)

  • Both jars are sealed with Vaseline so that no air enters.

  • After sometime it is observed that the leaves of the plant near which KOH plate was kept, did not show test for starch as KOH absorbs (1)

  • This proves that is necessary for photosynthesis.