Class 10 Science | Chapter-end Exercise & Answers | Chapter 6 | Life Processes

1. The kidneys in human beings are a part of the system for

(i) nutrition                               (ii) respiration

(iii) excretion                           (iv) transportation


(iii) Excretion

2. The xylem in plants are responsible for

(i)       transport of water

(ii)     transport of food

(iii)    transport of amino acids

(iv)    transport of oxygen


(i) Transport of water

3. The autotrophic mode of nutrition requires

(i)        carbon dioxide and water

(ii)       chlorophyll

(iii)     sunlight

(iv)      all of the above


(iv) All of the above

4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in

(i)        cytoplasm

(ii)       mitochondria

(iii)     chloroplast

(iv)      nucleus


(ii) Mitochondria

5. How are fats digested in our bodies? Where does this process take place?


Digestion of fats takes place in the small intestine.
The bile salts present in the bile juice emulsify the fats. By this, large globules break down into fine globules to provide larger surface area for the enzyme action.

Lipase enzyme in the pancreatic juice digests the emulsified fats. Lipase from intestinal juice converts fats into fatty acids and glycerol.

6. What is the role of saliva in the digestion of food?


Saliva contains salivary amylase enzyme that breaks down starch into sugars like maltose.

Saliva also helps in chewing and breaking down the food.

7. What are the necessary conditions for autotrophic nutrition and what are its by-products?


·    Presence of chlorophyll.

·    Supply of water to green plants.

·    Sufficient sunlight.

·    Sufficient supply of CO2.

By-product of autotropic nutrition is oxygen.

8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.


Aerobic respiration

Anaerobic respiration

Occurs in presence O2.

Occurs in absence of O2.

Complete breakdown of food occurs.

Partial breakdown of food occurs.

The end products are CO2 and water.

The end products may be ethanol & CO2 or lactic acid.

Produces much energy.

Produces less energy.

Organisms that use anaerobic respiration are yeast, bacteria etc.

9. How are the alveoli designed to maximise the exchange of gases?


·  Alveoli are balloon-like structures that increase surface area for gas exchange.

· Alveoli are thin walled and richly supplied with a network of blood vessels to facilitate gas exchange between blood and alveoli.

10.  What would be the consequences of a deficiency of haemoglobin in our bodies?


Oxygen carrying capacity decreases. As a result, the production of energy by oxidation will become slower. It causes problems such as anaemia.

11.  Describe double circulation in human beings. Why is it necessary?


In humans, blood goes through the heart twice during each cycle. This is called double circulation. It is described as follows:

· Oxygenated blood from the lungs left atrium relaxes blood enters left atrium left atrium contracts & left ventricle relaxes blood enters left ventricle left ventricle contracts blood is pumped out to the body.

· Deoxygenated blood from the body right atrium relaxes blood enters right atrium right atrium contracts & right ventricle dilates blood transfers to right ventricle right ventricle contracts blood is pumped into lungs for oxygenation.

Necessity of double circulation: It prevents mixing of deoxygenated and oxygenated blood. This ensures a highly efficient supply of oxygen to the body. This is useful get energy to maintain body temperature.

12.  What are the differences between the transport of materials in xylem and phloem?




Conducts water and dissolved minerals from roots to leaves.

Conducts prepared food material from leaves to other parts.

Transport of material takes place through vessels and tracheids.

Transport of material takes place through sieve tubes & companion cells.

Upward movement of water and dissolved minerals is mainly achieved by transpiration pull.

In translocation, material is transferred into phloem tissue using energy from ATP. This increases the osmotic pressure that moves the material in the phloem to tissues.

13.  Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.




Functional units of lungs.

Functional units of kidney.

Alveoli increase surface area for gas exchange.

Long and coiled tube of nephrons help in the reabsorption of filtrate.

The gas exchange of takes place through the network of capillaries in alveoli.

The Bowman’s capsule regulates the concentration of water and salts.

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