NCERT Solutions for Class 10 Science Chapter 6 Life Processes

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NCERT Solutions for Class 10 Science Chapter 6 Intext Questions

This article on NCERT Solutions for Class 10 Science Chapter 6 Life Processes provides clear, accurate, and easy-to-understand answers to all the questions from the NCERT textbook. These solutions help students understand important topics such as nutrition, respiration, transportation, and excretion in living organisms. Whether you are preparing for your school exams, board exams, or revising key concepts, these NCERT Solutions for Class 10 Science Chapter 6 Life Processes make learning simple and effective. Each answer is explained in student-friendly language to help you build a strong understanding of the chapter and score better in your upcoming Board examinations.

Page Number: 95

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

Answer:

Multicellular organisms like humans have large, complex bodies made of trillions of cells. Most of our internal cells are deep inside the body and are not in direct contact with the surrounding environment. Simple diffusion is a very slow process. If we relied only on diffusion, it would take a lot of time to circulate oxygen to all the body cells. Therefore, diffusion is insufficient to meet the oxygen requirements of multicellular organisms.

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

Answer:

An organism is considered alive if it carries out basic life processes such as nutrition, respiration, transportation, growth, movement, excretion, and reproduction. These activities show that the organism is living. In the case of non-living organisms, these processes do not take place. Even if some movements are not visible, the presence of life processes is the main criterion used to decide whether something is alive.

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

Answer:

Food, water, and oxygen are the outside raw materials that are used by an organism to carry out different life processes. Food provides energy and materials for growth and repair. Water helps in various body activities, and oxygen is used during respiration to release energy from food. The type and amount of raw materials needed may differ from one organism to another, depending on their complexity and environment.

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

Answer:

The processes that are essential for maintaining life are nutrition, respiration, transportation, excretion, and control and coordination. Without these processes, an organism cannot survive.

Questions Page Number: 101

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

Answer:

Autotrophic Nutrition	Heterotrophic Nutrition
Organisms prepare their own food and is not dependent on any other organism.	Organisms cannot prepare their own food and depend on other organisms.
Food is prepared from CO₂_, water, and sunlight.	Food is obtained directly from plants or other animals.
Chlorophyll is required for food preparation.	Chlorophyll is not required for food preparation.
Examples: Green plants, algae, and some bacteria.	Examples: Humans, animals, fungi, and most bacteria.

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

Answer:

Plants require different raw materials for photosynthesis, and they obtain them from various sources:

Carbon dioxide: It is taken from the atmosphere through tiny pores present on leaves called stomata.
Water: It is absorbed from the soil by the roots and transported to the leaves.
Sunlight: It is obtained from the Sun as a natural source of energy.
Chlorophyll: It is already present in the chloroplasts of green parts of plants, mainly in leaves.

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

Answer:

The hydrochloric acid (HCl) present in the stomach plays an important role in digestion.

HCl creates an acidic medium necessary for the action of enzyme pepsin.

4. What is the function of digestive enzymes?

Answer:

The food we eat consists of highly complex, large molecules that our body cannot absorb directly. Digestive enzymes act as biological catalysts. Their primary job is to chemically break down these complex food particles into simpler food molecules so that they can be absorbed by the walls of the intestine. For example, they break down complex carbohydrates into glucose, proteins into amino acids, and fats into fatty acids.

There are various digestive enzymes present in the body, such as pepsin, trypsin, amylase, lipase, etc.

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

Answer:

The small intestine is specially designed to absorb digested food efficiently. Its inner lining has numerous finger-like projections called villi, which further contain microvilli. These structures greatly increase the surface area for absorption. Each villus is rich in blood vessels that quickly absorb the digested nutrients and carry them into the bloodstream, which then transports them to all parts of the body.

Questions Page Number: 105
1. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen
for respiration?

Answer:

Terrestrial organisms obtain oxygen directly from the atmosphere, where oxygen is present in a much higher concentration. This makes respiration easier and more efficient for them. In contrast, aquatic organisms depend on oxygen dissolved in water, which is available in much smaller amounts. As a result, aquatic organisms need to breathe faster to meet their oxygen needs, while terrestrial organisms do not face this limitation.

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

Answer:

The different ways in which glucose is oxidized to provide energy in various organisms
are:

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

Answer:

Oxygen and carbon dioxide are transported in the human body through the blood.
(i) Transport of oxygen : Oxygen does not dissolve easily in blood fluid. Haemoglobin present in red blood cells binds tightly with oxygen in the lungs and carries it to tissues across the body that are running low on oxygen.
(ii) Transport of carbon dioxide : Carbon dioxide is highly soluble in water. Therefore, most of the Carbon dioxide produced by our cells dissolves smoothly directly into the blood plasma.The plasma carries it back to the lungs, where it diffuses into the air spaces and is exhaled.

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

Answer:

The human lungs are highly efficient for gas exchange due to their special structure. Inside the lungs, the air passage divides repeatedly into smaller tubes and finally ends in tiny balloon-like structures called alveoli. These alveoli greatly increase the surface area available for gas exchange.
The walls of alveoli are very thin and are surrounded by an extensive network of blood capillaries. This allows oxygen to easily diffuse into the blood and carbon dioxide to move out of the blood into the alveoli.
During breathing, the movement of ribs and diaphragm helps air to enter and leave the lungs, ensuring a continuous supply of fresh oxygen and removal of carbon dioxide. The large number of alveoli together provides a very large surface area, making gas exchange fast and efficient.

Questions Page Number: 110
1. What are the components of the transport system in human beings? What are the functions of these
components?

Answer:

The human transport system (circulatory system) consists of three main components: the heart, blood, and blood vessels.

Heart: It acts as a pump. It sends oxygen-rich blood to all parts of the body and brings back deoxygenated blood to the lungs for oxygenation.
Blood: It is the main fluid of the transport system.
It carries oxygen, carbon dioxide, nutrients, hormones, and waste materials like urea.
It consists of white blood cells (WBCs), which are the main component of our immune system.
It also consists of platelets that cause the clotting of blood.
Blood vessels: These include arteries, veins, and capillaries. They form a network that carries blood from the heart to different parts of the body and brings it back to the heart. All arteries carry oxygenated blood except pulmonary arteries, and they transport blood from the heart to various parts of the body, while all veins carry deoxygenated blood except pulmonary veins. Capillaries help in the exchange of materials between blood and body tissues.

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

Answer:

Mammals and birds are warm-blooded animals, so they need to maintain a constant body temperature. For this, they require a massive, continuous supply of energy generated through cellular respiration. To produce this huge amount of energy, the body cells require a highly efficient and constant supply of oxygen.

The complete separation of oxygenated and deoxygenated blood ensures that the body gets a highly efficient oxygen supply. This improves energy production and helps in maintaining a stable body temperature, regardless of the surrounding environment.

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

Answer:

The transport system in highly organised plants consists of vascular tissues, mainly xylem and phloem.

Xylem: It transports water and minerals absorbed by the roots to all parts of the plant.
Phloem: It transports food prepared in the leaves to different parts of the plant body.

4. How are water and minerals transported in plants?

Answer:

Water and minerals travel upward from roots to stems and leaves through the xylem tissue by a combination of two forces:

Root pressure:Root cells actively absorb ions (minerals) from the soil. This creates a higher concentration of ions inside the root than in the soil. Water then enters into the root by osmosis. This creates an upward push called root pressure that pushes water up into the xylem vessels.
Transpiration pul: As water evaporates from leaf cells through the stomata (transpiration), it creates a suction force that pulls water in the xylem upward from the roots. This pulling force is called transpiration pull. This, transpiration pull is the major driving force for upward water movement during the day.

Answer:

The food is produced in the leaves of the plants through the process of photosynthesis. It is then transported to various parts of the body through phloem tissues. This food is mainly transported in the form of sucrose. This process is called translocation and requires energy in the form of ATP. The food is loaded into the phloem tissue, which increases the osmotic pressure of the tissue. As a result, water enters the phloem by osmosis. This pressure then pushes the food to tissues with less pressure(roots, fruits, seeds), according to the plant’s needs.

Questions Page Number: 112
1. Describe the structure and functioning of nephrons.

Answer:

Nephrons are the structural and functional units of the kidneys. Each kidney contains millions of nephrons that help in filtering blood and forming urine.

Structure of a Nephron:

A nephron mainly consists of two parts:

Bowman’s capsule and glomerulus:
Bowman’s capsule is a cup-shaped structure that contains a network of tiny blood capillaries called the glomerulus. Blood enters the glomerulus through the renal artery, where filtration takes place.
Renal tubule:
It is a long coiled tube connected to Bowman’s capsule. The filtrate passes through this tubule, where useful substances are reabsorbed.

Functioning of a Nephron:

Blood is filtered in the glomerulus, and the filtered fluid enters Bowman’s capsule.
The filtrate contains water, salts, glucose, amino acids, and waste materials like urea.
As the filtrate moves through the renal tubule, useful substances such as glucose, amino acids, salts, and most of the water are reabsorbed into the blood.
The remaining waste material forms urine.
The urine passes into collecting ducts, then into the ureter, where it is carried to the urinary bladder for storage before being removed from the body.

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

Answer:

Plants use different methods to remove excretory products from their body.

Excess water is removed through transpiration from the leaves.
Gaseous wastes such as oxygen and carbon dioxide are released through stomata in leaves by diffusion.
Some waste substances are stored in leaves that fall off.
Wastes may also be stored in the form of gums and resins.
Some waste materials are released into the soil through the roots.

3. How is the amount of urine produced regulated?

Answer:

If there is a high concentration of toxic nitrogenous wastes (like urea) running through your blood, the kidneys require more water to dissolve and flush those toxins out safely, which increases urine volume.

The amount of urine that is regulated depends upon the amount of water and other substances that are present.

Quantity of water : If there is more water in the body then the renal tubules reabsorb very little water. This results in a large volume of dilute urine. Conversely, if there is less water in the body, the kidneys reabsorb more water, then a small quantity of concentrate urine is excreted.
Quantity of dissolved wastes : When there is more quantity of dissolved wastes like urea, uric acid and salts in the body, more quantity of water is required to excrete them. Therefore, the amount of urine produced increases.
Hormones: The amount of urine produced is also regulated by certain Antidiuretic hormone (ADH).

Questions Page Number: 113
1. The kidneys in human beings are a part of the system for
(a) nutrition
(b) respiration
(c) excretion
(d) transportation

Answer:

(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

Answer:

(a) transport of water

3. The autotrophic mode of nutrition requires
(a) carbon dioxide and water
(b) chlorophyll
(c) sunlight
(d) all of the above
Solution:

(d) 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
Answer:
(ii) Mitochondria

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

Answer:

Fats are digested in the small intestine. Bile juice secreted by the liver is poured into the small intestine along with pancreatic juice. The bile salts break down the large fat globules into smaller fat globules. This process is called emulsification. Therefore, by emulsification, large globules break down into fine globules to provide larger surface area to act upon by the enzymes.

The pancreas secretes pancreatic juice containing the enzyme lipase, which breaks down emulsified fats. Glands present in the wall of small intestine secrete intestinal juice, which contains enzyme that converts fats into fatty acids and glycerol.

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

Answer:

Saliva helps in the digestion of food in several ways. It moistens and softens the food, making it easier to chew and swallow. Saliva also contains an enzyme called salivary amylase, which begins the digestion of starch by breaking it into simpler sugars. In this way, digestion starts in the mouth itself.

7. What are the necessary conditions for autotrophic nutrition, and what are its byproducts?

Answer:

The necessary conditions for autotrophic nutrition are sunlight, chlorophyll, carbon dioxide, and water. Green plants use these materials to prepare their own food through the process of photosynthesis.

The by-products of autotrophic nutrition are the carbohydrates in the form of glucose (food) and the release of oxygen into the atmosphere.

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

Aerobic Respiration	Anaerobic Respiration
It takes place in the presence of oxygen.	It takes place in the absence of oxygen.
Glucose is completely broken down.	Glucose is partially broken down.
The end products are carbon dioxide, water, and energy.	The end products are ethanol and carbon dioxide or lactic acid along with a small amount of energy.
A large amount of energy is released.	Only a small amount of energy is released.
It occurs in most plants and animals.	It occurs in yeast, some bacteria, and human muscle cells during heavy exercise.

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

Answer:

The alveoli are tiny, balloon-like air sacs that greatly increase the surface area inside the lungs. The walls of alveoli are very thin and are surrounded by a dense network of blood capillaries. This allows oxygen to quickly diffuse into the blood and carbon dioxide to move out of the blood into the alveoli. Because there are millions of alveoli in the lungs, a large amount of air comes in contact with blood at the same time, which maximises the exchange of gases.

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

Answer:

Haemoglobin is found in red blood cells that carries oxygen from the lungs to all parts of the body. If there is a deficiency of haemoglobin, the oxygen-carrying capacity of the blood decreases. As a result, less oxygen reaches the body cells, and energy production becomes slow. A person may feel weak, tired, and low on stamina. Severe deficiency can lead to anaemia, a condition in which the body does not get enough oxygen for normal functioning.

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

Answer:

Double circulation is a process in which blood passes through the heart twice in one a single cycle

It consists of two parts:

Pulmonary circulation: Pulmonary circulation starts from the right ventricle and ends in the left atrium. The deoxygenated blood collected from the body is brought to the right atrium, where it is sent to right ventricle. The right ventricle pumps this impure blood to the lungs for oxygenation through pulmonary artery. The oxygenated blood from lungs again enters the left atrium of the heart through pulmonary veins.
Systemic circulation: While the systemic circulation starts from the left ventricle and ends in the right atrium. From the left atrium it is send to left ventricle, from where this oxygenated blood is pumped to different parts of body. The deoxygenated blood returns back to the right right atrium of the heart. In this way the blood flows through the heart twice, that’s why it is called ‘double circulation’.

Importance Of Double Circulation:

Double circulation is necessary because it keeps oxygenated and deoxygenated blood completely separate. This ensures that body tissues receive a continuous and efficient supply of oxygen, which is essential for high energy production and maintaining body temperature in humans.

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

Solution:

Xylem	Phloem
Xylem transports water and minerals from roots to all parts of the plant.	Phloem transports food prepared in leaves to all parts of the plant.
The movement is mainly upward (from roots to leaves).	The movement can be both upward and downward.
Xylem tissue is made up of dead cells like vessels and tracheids.	Phloem is made up of living cells like sieve tubes and companion cells.
Transport in xylem occurs mainly due to transpiration pull.	Transport in phloem requires energy (ATP) for movement of food.

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

Answer:

Structure

Alveoli (Lungs)	Nephrons (Kidneys)
Alveoli are tiny, balloon-like air sacs present in the lungs.	Nephrons are tubular structures present in the kidneys.
Their walls are very thin (one cell thick) and surrounded by a dense network of blood capillaries.	A nephron consists of Bowman’s capsule, glomerulus, and a long renal tubule. They are composed of a cluster of thin-walled capillaries.
They provide a large surface area for exchange of gases.	They provide a large surface area for filtration and urine formation.

Function

Alveoli (Lungs)	Nephrons (Kidneys)
Oxygen and carbon dioxide are exchanged between blood and alveolar air.	Blood is filtered, and useful substances are reabsorbed while wastes are removed as urine.
They are the main site of respiration (gas exchange).	They are the main functional units for excretion and removal of nitrogenous wastes.

NCERT Solutions for Class 10 Science Chapter 6 Life Processes

NCERT Solutions for Class 10 Science Chapter 6 Intext Questions

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