NCERT Solutions for Class 10 Science Chapter 6 Life Processes

By using NCERT Solutions for Class 10 Science Chapter 6 Life Processes, students will be able to get an accurate gauge of their understanding of the concepts taught in class. These CBSE Class 10 NCERT Solutions are created by experts of Gkrankers.com who have years of experience in the field of education.

Chapter 6 Class 10 Science NCERT solutions are explained in a step-by-step manner, which makes it easy for students to understand. It help students in revising the chapter properly.

Chapter 6 Life Processes Class 10 Science NCERT Solutions

In Text Questions

1. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?

Solution

In multicellular organisms, all the cells of the body may not be in direct contact with the source of oxygen, i.e., the environment. Therefore, diffusion is insufficient to meet all the oxygen requirements of all the cells. These organisms are therefore dependent on specialized organs in order to meet their oxygen requirements.

2. What criteria do we use to decide whether something is alive?

Solution

When we determine whether an organism is alive, we look for movement, growth, metabolic activity, cell body organization, nutrition, respiration, transport of substances within the organism’s body, excretion, and response to stimuli.

3. What are outside raw materials used for by an organism?

Solution

(i) Food: It is the source of energy.
(ii) Oxygen: It is required for breaking down of carbon based molecules to liberate energy in the body.
(iii) Water: It is required for proper digestion of food and other functions in the body.

4. What processes would you consider essential for maintaining life?

Solution

(i) Nutrition
(ii) Respiration
(iii) Transportation
(iv) Growth and repair
(v) Excretion.

1. What are the differences between autotrophic nutrition and heterotrophic nutrition?

Solution

Autotrophic Nutrition	Heterotrophic Nutrition
It is the nutrition in which organic food is manufactured from inorganic raw materials.	It is the nutrition in which organic food is obtained from various sources.
An external source of energy (sun) is required for synthesis of organic substance (photosynthesis).	Exergy is obtained by oxidation of food (organic substance).
The organism lives and depends on inorganic medium.	The organism depends and must live in contact with sources of organic matter.
The nutrition takes place by synthesis of complex substance from simple molecules.	The nutrition is by intake of solid food in some cases.
It is found in green plants.	It is found in animals, man, non-green plants, fungi and most of the bacteria.
Digestive process is absent.	The food is broken down into simpler forms by digestive process.

2. Where do plants get each of the raw materials required for photosynthesis?

Solution

In photosynthesis, CO₂ and water are the raw materials. Photosynthesis requires sunlight to provide energy. CO₂ comes from the air and enters leaves through stomatal openings. The roots absorb water from the soil, which enters leaves through the midrib and veins.

3. What is the role of the acid in our stomach?

Solution

(i) It provides the acidic medium which is required for the action of enzymes. It changes the pH of food.
(iii) It destroys the bacteria present in food.

4. What is the function of digestive enzymes?

Solution

Digestive enzymes convert the non-diffusible form of food into diffusible form.
(a) Ptyalin converts starch (complex carbohydrates) into maltose.
(b) Pepsin breaks down proteins into peptides and amino acids.
(c) Lipase acts on fats and forms fatty acid and glycerol.
(d) Maltase acts on maltose and forms glucose.

5. How is small intestine designed to absorb digested food?

Solution

Small intestine has several finger-like projections called villi. These are specially adapted/designed for absorption. They have a dense network of blood capillaries and lymph which helps to carry the absorbed food material in blood to different parts of the body.

1. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?

Solution

Oxygen is obtained by aquatic organisms from dissolved oxygen in water, which is comparatively less than oxygen in the atmosphere, which is why terrestrial organisms are at an advantage because they get their oxygen directly from the air and in large quantities.

2. What are the different ways in which glucose is oxidised to provide energy in various organisms?

Solution

3. How is oxygen and carbon dioxide transported in human beings?

Solution

Oxygen combines with haemoglobin and forms a compound oxyhaemoglobin. Thus, it is transported in a compound state. Carbon dioxide dissolves in water present in blood and is transported in dissolved state in human beings.

4. How are the lungs designed in human beings to maximise the area for exchange of gases?

Solution

Within the lungs, the primary bronchi divides into smaller and smaller tubes which finally terminate into balloon-like structures called alveoli. These alveoli increase the surface area for exchange of gases. The walls of the alveoli are elastic and are supplied with capillaries. Through these thin walls gases are exchanged between the capillaries and the air sacs.

1. What are the components of the transport system in human beings? What are the functions of these components?

Solution

The components of the transport system in human beings are the heart, blood, and blood vessels.
(i) Blood. It transports digested food, oxygen, carbon dioxide and nitrogenous waste materials.
(ii) Heart. It pumps the deoxygenated blood to lungs for purification and oxygenated blood to different parts of the body tissues.
(iii) Blood vessels. They carry oxygenated blood to different parts of body tissues and deoxygenated blood to heart for pumping it to lungs for purification.

2. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

Solution

Animals that maintain their body temperature constant need energy to do so such as birds and mammals. To get obtain a constant supply of energy from food, sufficient amount of oxygen is needed at all times which is supplied by oxygenated blood. If oxygenated and deoxygenated blood is mixed in heart chambers, the efficiency of blood in carrying oxygen will decrease resulting in less energy production. This will not allow the animal to maintain its body temperature. Therefore, it is necessary to separate oxygenated and deoxygenated blood in such animals. Thus, they have separate chambers for it.

3. What are the components of the transport system in highly organised plants?

Solution

The components of the transport system in plants are:

(i) Xylem vessels and tracheid of roots, stems and leaves. They are concerned with the transport of water and minerals.
(ii) Phloem consists of sieve tubes and companion cells. It transports food, amino acid and other substances from leaves to various parts of plants.

4. How are water and minerals transported in plants?

Solution

Water and minerals are transported in plants by xylem tissue. The xylem tissue is present in roots, stems, branches and leaves. The root cells that are in close contact of soil uptake ions. This creates a difference between the concentration of ions in the root cells and soil. Due to which, water moves into the root cells to remove this difference. This forms a water column in the xylem tissue and is steadily pushed upwards. It is root pressure. Also the suction pull developed due to transpiration helps to pull up the water column in plants.

5. How is food transported in plants?

Solution

The food prepared in the green leaves of plants is transported through phloem in the form of sucrose solution to storage organs of roots, stems and fruits. This process is called translocation. Translocation occurs in the sieve tubes of phloem with the help of companion cells. It occurs both in upward and downward directions. This process requires energy. It is provided by ATP molecules. This increases osmotic pressure in the tissue causing water to move into it. This pressure moves the material in the phloem to tissues which have less pressure.

1. Describe the structure and function of nephrons.

Solution

A nephron is made up of a globular double walled Bowman’s capsule around a clump of capillaries or glomerulus and a tubule surrounded by blood capillaries. The nephron empties into a collecting duct. All the collecting ducts discharge into a central cavity of the kidney (pelvis) that connects to the ureter.

(i) Bowman’s capsule. It is a small cup-like structure. It has a tuft made up of a bunch of renal artery. It is called glomerulus or glomerular tuft. The diameter of inlet branch of renal artery is more than the diameter of outlet/out going branch of renal artery.

(ii) Tubular part. The Bowman’s capsule extends into a coiled tube called convoluted tubule. It extends further into a long thin loop. This loop again broadens and terminates into a collecting duct. The collecting duct is attached to many nephrons. The tubular part of nephron is covered by a network of blood capillaries.

Functioning of Nephrons: The primary function of nephrons is to remove all waste products from the blood. The blood passes via the glomerulus with high pressure, the small molecules are moved into the glomerular capsules. The cells present in each tube absorb different molecules excluding the glucose, water, and others. It regulates the fluid volume in our body.

2. What are the methods used by plants to get rid of excretory products?

Solution

A plant’s excretion system is different than an animal’s. Plants take advantage of oxygen during photosynthesis, which is a waste. Excess water is removed by stomata. Wastes like gum, resins, etc., are stored in the dead cells of xylem tissue, while other wastes are stored in cellular vacuoles and leaves. If the leaves contain wastes, they will eventually turn yellow and die. Some wastes are also released by roots in soil after plants drop leaves.

3. How is the amount of urine produced regulated?

Solution

The amount of urine released is very less in comparison to the amount filtered by the Bowman’s capsule. It is regulated by the amount of water present in the body. If the body has less water then the urine produced is less and concentrate. If the body has excess of water then the urine produced is frequent and dilute.

Exercises

1. The kidneys in human beings are a part of the system for:
(a) Nutrition
(b) Respiration
(c) Excretion
(d) Transportation

Solution

(c) Excretion

2. The xylem in plants is responsible for:
(a) Transport of water
(b) Transport of food
(c) Transport of amino acids
(d) Transport of oxygen

Solution

(a) Transport of water.

3. The autotrophic mode of nutrition requires:
(a) Carbon dioxide and water
(b) Chlorophyll
(c) Sunlight
(d) All of these

Solution

(d) All of these

4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in:
(a) Cytoplasm
(b) Mitochondria
(c) Chloroplast
(d) Nucleus

Solution

(b) Mitochondria

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

Solution

Fats are digested in the stomach and small intestine. Gastric juice contains a weak lipase enzyme, which hydrolyzes only a small amount of fat. Intestinal lipase enzymes complete digestion of fats, while pancreatic juice contains the strongest lipase enzyme, which hydrolyzes about two-thirds of fat. Digestive products of fats include fatty acids and glycerol.

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

Solution

Saliva of salivary glands of human contains a carbohydrate- digesting enzyme called salivary amylase (or ptyalin). It hydrolyses about 30-40% of starch of ingested food into maltose and isomaltose at pH 6.8.

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

Solution

The conditions necessary to sustain autotrophic life are carbon dioxide and water. A green pigment known as chlorophyll and sunlight are also required to carry out the process of photosynthesis. As a result of photolysis of water, oxygen is released during photosynthesis.

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

Solution

Aerobic Respiration	Anaerobic Respiration
It is the most common method of respiration which takes place in the higher organisms in the presence of oxygen.	It is common in lower organisms and muscle cells of higher organisms in the absence of oxygen.
The complete oxidation of glucose takes place to release CO2 + H2O + Energy.	The incomplete oxidation of glucose takes place to release alcohol or acid + H2O + Energy.
It produces more energy per glucose molecule, i.e., 36 ATPs.	It produces less energy per molecule, i.e., 2 ATPs.
It is completed in cytoplasm and mitochondria of cells.	It is completed in cytoplasm only.

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

Solution

In order to facilitate gas exchange, the alveoli are thinwalled (lined by an endothelium of flat cells), moist (by mucus), vascular (supplied by pulmonary capillaries), permeable, and numerous (about 700 million).

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

Solution

In the absence of haemoglobin, red blood cells cannot transport oxygen to body tissues from the lungs, resulting in hypoxia in body tissues. Hypoxia decreases energy delivery and metabolic rate.

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

Solution

The heart chambers are responsible for accepting and pumping the blood. Blood enters the heart two times.
(a) Once the blood enters the heart in right half as deoxygenated blood which is pumped to pulmonary arota and this is done for purification in lungs.
When blood reaches the lungs it is cleaned. The CO₂ is removed out from it and O₂ is added into it. This makes the blood oxygenated.
(b) Second time in left half as oxygenated blood received from pulmonary veins. This has to be pumped to rest of the body for use, i.e., for oxidation of food to release energy. This is known as double circulation. It is necessary to keep the deoxygenated blood separate and send it for purification so that oxygenated blood is supplied for energy release in tissue cells, constantly every time.

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

Solution

Transport of Materials in Xylem	Transport of Materials in Phloem
The transport of materials in xylem takes place from root cells to leaves.	The transport of materials in phloem takes place from leaves to other needy organs.
Materials are transported due to root pressure and suction pull.	Materials are transported due to needs and supply and due to less pressure.
Their transportation does not need energy.	Their transportation needs energy, e.g., sucrose.
The vessels involved in it are mostly dead.	The vessels, sieve tubes, companion cells are involved.
Materials transported are water and dissolved minerals.	Materials transported are sucrose, amino acids and other substances.

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

Solution

Functioning of Alveoli	Functioning of Nephrons
Lungs consist of several air sacs called alveoli.	Kidney consists of several nephrons also called filtration units.
Air sacs are surrounded by blood capillaries for exchange of respiratory gases: CO2 and O2.	Nephrons have blood capillaries called glomerulus in Bowman’s capsule that filter the blood. The capillaries on tubular part absorb the useful materials from filtrate.
The air gets packed in the air sacs. The O, moves into the blood and CO2 moves from the blood to the sacs. This helps in blood purification.	This helps in urine formation.