NCERT Science Solutions for Class 10 Chapter 6: Life Processes

NCERT Science Solutions For Class 10 Chapter 6 Life Processes: In this article, students will find the solutions to Science Chapter 6 of Class 10. The solutions provided here are properly explained so that even if a student doesn't remember the concept, then by reading the explanation, they will be able to understand the solution. These solutions will also help students to be better at learning and even in their homework. Doing homework fast will save time for self-study, which is a great choice, and since the answers are well explained, the theory part will also get revised.

NCERT Science Solutions for Class 10 Chapter 6 Inside Book Questions

Page Number: 95

Question 1:

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

Answer:

Humans are multicellular organisms made of cells, but human cells are not in direct contact with the outer environment. Since they are not in direct contact with the outer environment, the body cells would not be able to get oxygen as per their requirement by diffusion. Also, the distance between the gas exchange surface and the locations where oxygen is needed cannot be covered by diffusion because it's a very slow process. This is the reason why multicellular organisms like humans cannot meet the oxygen requirement through the process of diffusion.

Question 2:

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

Answer:

The most important criteria to decide whether something is alive are respiration and breathing. Apart from these two, something alive will also show growth and movement, such as walking.

Question 3:

What are outside raw materials used by an organism?

Answer:

Every organism relies on its surroundings to meet its needs. Any organism's need for raw materials requirements depends upon the complexity of the organism and its surroundings.

The following are some examples of external raw materials utilized by an organism to carry out life processes:

1. Food: It is a source of energy and resources.
2. Oxygen: It is necessary for the decomposition of food into energy.
3. Water: It is necessary for healthy food digestion and other bodily processes.

Question 4:

What processes would you consider essential for maintaining life?

Answer:

Processes essential for maintaining life are:

1. Nutrition
2. Respiration
3. Transportation
4. Excretion
5. Control and Coordination

Even when they are not actively doing any specific task, living things do not stop performing their maintenance role. Life becomes challenging if any of these processes are missing.

Page Number: 101

Question 1:

What are the differences between autotrophic nutrition and heterotrophic nutrition?

Answer:

Question 2:

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

Answer:

Plants are autotrophs. So that they can make their food, but to make food, they need raw materials. Plant raw materials are chlorophyll, sunlight, water, and carbon dioxide. These raw materials are, by default, provided by natural means.

1. Chlorophyll: This is a green pigment present in the chloroplast of the leaves, which are green in color. The green color is due to the presence of this chlorophyll. Plants with the absence of chlorophyll cannot make their food.
2. Sunlight: It is the primary source of energy for all kinds of living beings. And as everybody knows, sunlight comes from the sun.
3. Water: It is present below the soil, so the plant roots go deep inside the soil in search of water. The roots keep growing unless it finds water. If the roots cannot find water underground, it must be provided manually. Without a proper supply of water, plants may even die.
4. Carbon Dioxide: The earth's atmosphere is filled with various kinds of gases, and carbon dioxide is one of them, which plants use as a raw material for making food.

Question 3:

What is the role of the acid in our stomach?

Answer:

Hydrochloric acid is acid produced in the stomach, a very strong acid. This acid in our stomach carries various advantages, and some of them are:

1. The acid in the stomach is used to activate an enzyme called pepsin which is helpful in digestion as it breaks down food into smaller particles.
2. This acid produced is also helpful for our health because it kills the bacteria that may have entered our stomach along with the food.

Question 4:

What is the function of digestive enzymes?

Answer:

Digestive enzymes, as the name suggests, are a helpful material that helps digest our food. The food we eat generally is complex, which means that the food contains very complex molecules. These complex molecules need to be broken down into smaller molecules so that the walls of the intestine can easily absorb them. This is the main function of the digestive enzymes present inside our body.

Question 5:

How is the small intestine designed to absorb digested food?

Answer:

The small intestine is vital in absorbing food and transferring it into the blood, from where it goes to all body parts.

After getting absorbed in the intestine, the nutrients are then transferred to the blood, and it's the responsibility of the blood to carry those nutrients to all parts of the body. The small intestine is designed in such a way that it offers a maximum area for the absorption of the digested food.

Numerous finger-like projections are present in the inner lining of the small intestine, known as villi, and contain many blood vessels that help carry absorbed food to each body cell.

Page Number: 105

Question 1:

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

Answer:

Aquatic organisms get oxygen from the surrounding water. Since oxygen is in the dissolved state, the oxygen concentration is low, resulting in aquatic organisms breathing much faster.

Terrestrial organisms get their oxygen from the atmosphere, which is rich in oxygen concentration. Since terrestrial organisms are getting direct oxygen that is also in high quantity, they have a low breathing rate compared to aquatic organisms.

Question 2:

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

Answer:

The very beginning stage is the breakdown of the glucose molecules. Glucose contains 6 carbon molecules, and this breakdown process occurs in all organisms in cytoplasm cells. After the breakdown, it produces a compound of three carbon molecules known as pyruvate.

This pyruvate is further broken down differently in different organisms, where it produces different end products.

1. Anaerobic respiration: In various plants like yeast, anaerobic respiration (respiration in the absence of oxygen) produces carbon dioxide and ethanol as the end product after the breakdown of pyruvate.
2. Aerobic respiration: Aerobic respiration occurs in the presence of oxygen. In this respiration, the pyruvate is broken down to form water and three molecules of carbon dioxide and this reaction takes place in the presence of oxygen.
3. Lack of oxygen: Sometimes, there may be a lack of oxygen due to very fast respiration, which then converts this pyruvate into lactic acid. Generally, this happens during intense physical exercise, and the pyruvate in our muscles produces lactic acid due to which we experience a very bad cramp. Lactic acid is a three-carbon molecule compound.

Question 3:

How are oxygen and carbon dioxide transported in human beings?

Answer:

Oxygen and Carbon dioxide in human beings is transported in the following way:

1. Transport of Oxygen: The lungs take in the air from the atmosphere, and after that, the air gets filtered to extract oxygen. The oxygen is then carried by hemoglobin present in the red blood cells to tissues and other parts of the body.
2. Transport of Carbon dioxide: Carbon dioxide is a compound dissolved in water. Since it is soluble in water, it is transported from tissues to lungs in the dissolved form. The blood plasma carries carbon dioxide from tissues to the lungs, where it diffuses from the blood to air in the lungs.

Question 4:

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

Answer:

The air passage inside the lungs becomes smaller and smaller tubes known as bronchi, and further, it forms bronchioles. The bronchioles then end in a balloon-like structure known as alveoli. These alveoli inside the lungs provide the maximum surface area required for exchanging gases. The alveoli have a very fine network of blood vessels and thin walls, which helps to facilitate the exchange of gases.

Page Number: 110

Question 1:

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

Answer:

The transport system, specifically the circulatory system, has three main components: heart, blood, and blood vessels.

1. Heart - The heart receives the deoxygenated blood from all body parts and transfers it to the lungs to increase oxygen concentration. After enriching the blood with oxygen and purifying it, the lungs send it back to the heart.
2. Blood - The main responsibility of the blood is to transport digested food, oxygen, hormones, and nitrogenous wastes like urea and carbon dioxide. It also fights against foreign particles and makes our body immune to diseases. It also helps to regulate body temperature.
3. Blood Vessels - Blood Vessels are responsible for carrying blood from the heart to other parts of the body and also from other parts of the body to the heart. Various blood vessels like arteries, veins, and capillaries are responsible for achieving this task.

Question 2:

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

Answer:

Oxygenated blood is rich in oxygen, while deoxygenated blood is deficient in oxygen. Oxygenated blood provides oxygen to all body parts because mammals and birds carry out many activities. To carry out these activities, birds and mammals need a constant oxygen concentration inside the body. It also helps to regulate body temperature. This is why separating oxygenated and deoxygenated blood in mammals and birds is necessary.

Question 3:

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

Answer:

Properly developed plants contain two most important conducting tissues: the xylem and phloem.

1. Xylem - The xylem consists of various cells, tracheids, and vessels. The vessels are interconnected with tracheids, forming a continuous system and making a channel for a water passage through which the water is passed to all the parts of the plant. The main function of the xylem tissue is to carry water and other useful nutrients to all parts of the plant.
2. Phloem - Phloem carries soluble products formed during photosynthesis from leaves to different parts of the plant.

Question 4:

How are water and minerals transported in plants?

Answer:

Water and minerals are mainly transported through the roots of the plant. Roots have hair known as root hair in direct contact with the water in soil particles. The process of diffusion helps the water and minerals to get into the root hair, which is further passed on from cell to cell by the process of osmosis. It even passes through the epidermis, root cortex, and endodermis and finally reaches the root xylems.

The xylem vessels inside the root are connected with the plant's stem's xylem vessels, which is why the water and minerals are transported from the roots to the stems. The xylem vessels of roots carry useful nutrients to the xylem vessels of the stem.

The stems of the plants are branched into leaves, and the water and minerals are carried to these parts through xylem vessels. So this way, the useful nutrients are carried by the xylem to all the parts of the plant.

Now, the roots are continuously absorbing water, but why? Roots continuously absorb water because when plants lose water from their cells through evaporation, it creates a suction force inside xylem vessels, resulting in the water being pulled from the roots. This loss of water by plants through evaporation is known as transpiration.

Question 5:

How is food transported in plants?

Answer:

Plants transport food through phloem tissues which require energy, and this food movement in plants is known as translocation. The sugar, the form of food in plants, is loaded in a sieve tube of phloem tissue. The food is prepared with leaves, and the loading process requires energy gained from ATP.

After this, the water enters into the sieve tube by the process of osmosis which regulates pressure and increases it, and because of this high pressure, food is transported to all parts of the plants having low pressure. This is how food is transported in plants.

Page Number: 112

Question 1:

Describe the structure and functions of nephrons.

Answer:

Structure of Nephron

Each nephron has two parts, among which the first one is Bowman's Capsule which is present at the upper end and looks like a cup-shaped bag. The Bowman's Capsule consists of a network of blood capillaries known as the glomerulus. The renal artery connects to one end of the glomerulus, which is responsible for bringing impure blood containing urea waste for filtration.

The second part of the nephron is coiled, where the important substances, if present, are reabsorbed by the body. After the reabsorption process, whatever substance is left is urine which contains urea and is expelled from the body from time to time. This substance may be amino acids, ions, water, or glucose.

Functions of Nephron

1. Nephron is responsible for filtration of blood which takes place in Bowman's Capsule where glomerulus capillaries are also involved.
2. After the filtration, the filtrate may contain nutrients useful for the body, like amino acids, glucose, water, and salts. If it is present, it is reabsorbed by capillaries around the nephron.
3. After reabsorption, only urine is left, which contains nitrogenous wastes. The urine gets collected from the nephron and goes to the urinary bladder through the ureter.

Question 2:

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

Answer:

Plants use various methods to get rid of excretory products.

1. Stomata present on leaves of the plants, which helps in gaseous exchange. Some plants have lenticels through which gaseous exchange takes place.
2. The stored solid or liquid waste is removed by falling fruits, shedding leaves, or peeling bark.
3. Plants secrete their waste through gums and resins.
4. Sometimes, plants get rid of waste by releasing it into the soil.

Question 3:

How is the amount of urine produced regulated?

Answer:

The kidney mainly regulates the amount of urine produced inside the body. The regulation depends on the quantity of excess water and the amount of waste present in the water.

1. Quantity of Water: When water concentration is very high in tissues, a large quantity of dilute urine is excreted. If the water concentration is less, then a small quantity of concentrated urine is excreted.
2. Quantity of dissolved wastes: If the waste inside the body, especially the nitrogenous wastes like urea and uric acid, are in large quantities, then a large amount of water is required to excrete them means the urine produced will be greater in amount.
3. Hormones: Some hormones inside the body are also responsible for regulating urine. These hormones control the movement of sodium ions and water in nephrons.

NCERT Solutions for Class 10 Science Chapter 6 Exercise Solutions

Question 1:

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

1. nutrition
2. respiration
3. excretion
4. transportation

Answer:

iii.) Excretion: The excretion process takes place inside the kidney and helps the body to get rid of nitrogenous wastes in the form of urine.

Question 2:

The xylem in plants is responsible for

1. transport of water
2. transport of food
3. transport of amino acids
4. transport of oxygen

Answer:

i.) Transport of water: Xylem tissues are present all over the plants from root to tip of the shoot, so the water and other useful nutrients absorbed from roots go to all parts of the plants from cell to cell.

Question 3:

The autotrophic mode of nutrition requires

1. carbon dioxide and water
2. chlorophyll
3. sunlight
4. all of the above

Answer:

iv.) All of the above - Autotrophic modes of nutrition are mainly shown by green plants containing chlorophyll in the presence of carbon dioxide, water, and sunlight. Without these materials, autotrophs cannot make their food.

Question 4:

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

1. cytoplasm
2. mitochondria
3. chloroplast
4. nucleus

Answer:

ii.) Mitochondria

Question 5:

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

Answer:

Fats are mainly digested in the small intestine of the body. The liver produces bile juice pouring into the intestine and the pancreatic juice. The bile salts then emulsify the large globules of fats in bile juice. The process is known as emulsification, where the large fat globules are broken down into small fat globules, and in return, it provides a larger surface area for enzymes to act upon.

Now the pancreatic juice contains an enzyme known as lipase. This lipase's job is to break down the emulsified fats. Also, the glands on the walls of the small intestine secret intestinal juice, which contains lipase enzymes and converts fats into glycerol and fatty acids.

Question 6:

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

Answer:

Saliva is helpful in the digestion of food because it contains an enzyme called salivary amylase, whose function is to break down starch into sugar products like maltose. This is done because starch is a complex sugar while maltose is a simple sugar.

Saliva produced in the mouth helps keep the mouth cavity clean and moistens the food, which makes it easy to chew and swallow.

Question 7:

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

Answer:

There are various conditions needed for the autotrophic mode of nutrition. Firstly there should be the presence of chlorophyll in plants, and also, there should be a proper supply of water. Sunlight and carbon dioxide should be present in sufficient amounts, without which the autotrophic mode of nutrition would not take place.

Oxygen is released as the by-product during the autotrophic mode of nutrition.

Question 8:

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

Answer:

Yeast and Bacteria are examples of organisms that show the anaerobic mode of respiration.

Question 9:

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

Answer:

1. There are ballon-like structures present in alveoli that increase surface area and thus help in the exchange of gases.
2. Alveoli have a great network of blood vessels and help exchange of gases between blood and air inside alveoli.

Question 10:

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

Answer:

Hemoglobin in the blood is an essential material whose primary job is carrying oxygenated blood. A deficiency of hemoglobin means less transportation of oxygen to the body parts. Less oxygen will result in slower production of energy by oxidation. Because of these reasons, a person may fall sick or feel dizzy and lazy most of the time if there is a hemoglobin deficiency.

Question 11:

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

Answer:

The blood movement in our body is organized so that it enters the heart twice and leaves the heart twice. The deoxygenated blood is carried from different parts of the body to the heart, and through the vena cava, the blood enters the heart's right atrium. Deoxygenated blood is sent to the right ventricle from the right atrium, where the blood is pumped into the lungs for oxygenation. The blood is carried to the lungs by the pulmonary artery.

Oxygenated blood reaches all parts of the body. The deoxygenated blood is enriched with oxygen, and from the lungs, it is sent to the left atrium through pulmonary veins. From the left atrium, the oxygenated blood is sent to the left ventricle, and the left ventricle pumps the oxygenated blood into arteries.

The blood flows twice from the heart and is called double circulation.

Double circulation is necessary because it doesn't allow mixing oxygenated blood with deoxygenated one. Also, it helps to increase oxygen concentration by keeping the blood separated. Thus constant energy and temperature regulation are maintained in the human body.

Question 12:

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

Answer:

Question 13:

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

Answer: