Class 10th Science Chapter 6 Life Processes long Questions & Answers NCERET BOOK

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Chapter - Life Process

Question 1: 

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

(a) nutrition.

(b) respiration.

(c) excretion.

(d) transportation.

Answer : (c) excretion.

Question 2: 

The xylem in plants are responsible for

(a) transport of water.

(b) transport of food.

(c) transport of amino acids.

(d) transport of oxygen.

Answer : (a) transport of water.

Question 3: 

The autotrophic mode of nutrition requires

(a) carbon dioxide and water.

(b) chlorophyll.

(c) sunlight.

(d) all of the above.

Answer : (d) all of the above.

Question 4: 

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

in

(a) cytoplasm.

(b) mitochondria.

(c) chloroplast.

(d) nucleus.

Answer : (b) mitochondria.

Question 5: 

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

Answer : Fats are present in the form of large globules in the small intestine. The small 

intestine gets the secretions in the form of bile juice and pancreatic juice 

respectively from the liver and the pancreas. The bile salts (from the liver) break 

down the large fat globules into smaller globules so that the pancreatic enzymes 

can easily act on them. This is referred to as emulsification of fats. It takes place 

in the small intestine.

Question 6: 

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

Answer : Saliva is secreted by the salivary glands, located under the tongue. It makes the 

food soft for easy swallowing. It contains a digestive enzyme called salivary 

amylase, which breaks down starch into sugar.

Question 7: 

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

Answer : Autotrophic nutrition takes place through the process of photosynthesis. Carbon 

dioxide, water, chlorophyll pigment, and sunlight are the necessary conditions 

required for autotrophic nutrition. Carbohydrates (food) and O2 are the by-

products of photosynthesis.

6CO2 + 6H2O + 𝐶ℎ𝑙𝑜𝑟𝑜𝑝ℎ𝑦𝑙𝑙 𝑎𝑛𝑑 𝑆𝑢𝑛𝑙𝑖𝑔ℎ𝑡 → C6H12O6 + 6O2

Question 8: 

What are the differences between aerobic and anaerobic respiration? Name some

organisms that use the anaerobic mode of respiration.

Answer : Difference between Aerobic respiration and Anaerobic respiration are following :

Aerobic respiration	Anaerobic respiration
1. It occurs in the presence of O2.  2. It involves the exchange of gases  between the organism and the  outside environment. 3. It occurs in cytoplasm and  mitochondria. 4. It always releases CO2 and H2O.  5. It yields large amount of energy.	1. It occurs in the absence of O2 2. Exchange of gases is absent.  3. It occurs only in cytoplasm. 4. It produces alcohols and CO2. 5. Energy released is very low.

Anaerobic respiration occurs in the roots of some waterlogged plants, some 

parasitic worms, animal muscles and some micro-organisms such as yeasts.

Question 9: 

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

Answer : The alveoli are the small balloon-like structures present in the lungs. The walls of the alveoli consist of extensive network of blood vessels. Each lung contains 300−350 million alveoli, making it a total of approximately 700 million in both the lungs. The alveolar surface when spread out covers about 80 m2 area. This large surface area makes the gaseous exchange more efficient.

Question 10: 

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

Answer : Haemoglobin is the respiratory pigment that transports oxygen to the body cells 

for cellular respiration. Therefore, deficiency of haemoglobin in blood can affect the oxygen supplying capacity of blood. This can lead to deficiency of oxygen in the body cells. It can also lead to a disease called anaemia.

Question 11: 

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

Answer : Because both oxygen and carbon dioxide have to be transported by the blood, the heart has different chambers to prevent the oxygen-rich blood from mixing with the blood containing carbon dioxide. The human heart is divided into four chambers − the right atrium, the right ventricle, the left atrium and the left ventricle.

Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left, the left atrium. The left atrium relaxes when it is collecting this blood. It thencontracts, while the next chamber, the left ventricle, expands, so that the blood is transferred to it. When the muscular left ventricle contracts in its turn, the blood is pumped out to the body.

De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it expands. As the right atrium contracts, the corresponding lower chamber, the right ventricle, dilates. This transfers blood to the right ventricle, which in turn pumps it to the lungs for oxygenation. During this process blood goes twice through the heart. That’s why it is known as double circulation.

Double Circulation is necessary:

The separation of oxygenated and de-oxygenated blood allows a more efficient supply of oxygen to the body cells. This efficient system of oxygen supply is very useful in warm blooded animals such as human beings. As we know, warm-blooded animals have to maintain a constant body temperature by cooling themselves when they are in a hotter environment and by warming their bodies when they are in a cooler environment.  Hence, they require more O2 for more respiration so that they can produce more energy to maintain their body temperature. 

Question 12: 

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

Answer : 
Difference between Xylem and Phloem:

Xylem	Phloem
1. Xylem tissue helps in the  transport of water and minerals. 2. Water is transported upwards  from roots to all other plant parts. 3. Transport in xylem occurs with  the help of simple physical forces  such as transpiration pull.	1. Phloem tissue helps in the transport of food. 2. Food is transported in both  upward and downward  directions. 3. Transport of food in phloem requires energy in the form of  ATP.

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Page : 95 

Question 1. 

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

Answer:  
In multicellular organisms, only the cells present in the surface layer are in direct contact with the surrounding environment, whereas other cells are not. Therefore, diffusion is insufficient to meet the oxygen requirements of multicellular organisms like humans. 

Question 2: 

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

Answer :

Any visible movement such as walking, breathing, or growing is generally used 

to decide whether something is alive or not. However, a living organism can also 

have movements, which are not visible to the naked eye. Therefore, the presence 

of molecular movement inside the organisms use to decide whether something 

is alive or not.

Question 3: 

What are outside raw materials used for by an organism?

Answer :

An organism uses outside raw materials mostly in the form of food (Since life on 

earth depends on carbon based molecules, most of these food sources are also 

carbon-based) and oxygen. The raw materials required by an organism can be 

quite varied depending on the complexity of the organism and its environment 

Question 4: 

What processes would you consider essential for maintaining life?

Answer :

Life processes such as nutrition, respiration, transportation, excretion, etc. are 

essential for maintaining life.

Page : 101

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

Answer.

Autotrophic nutrition	Heterotrophic nutrition
1. The organism prepares its own food.	1. The organism does not prepares its own food.
2. It is not dependent on any other organism for their food. Example: Green plants.	2. It is dependent on other organisms for food. Examples: Man, dogs, lions snakes, etc.

Question 2: 

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

Answer :

The following raw materials are required for photosynthesis:

(i)The raw material CO2 enters from the atmosphere through stomata.

(ii)Water is absorbed from the soil by the plant roots.

(iii)Sunlight, an important component to manufacture food, is absorbed by the

chlorophyll and other green parts of the plants.

Question 3 . 
What is the role of the acid in our stomach?
Answer:
The acid (hydrochloric acid) formed in our stomach helps in killing unwanted harmful germs which may have gained entry along with the food. It is secreted by the gastric glands creates an acidic medium which facilitates the action of the pepsin enzyme.

Question 4: 

What is the function of digestive enzymes?

Answer :

Digestive enzymes such as amylase, lipase, pepsin, trypsin, etc. help in the 

breaking down of complex food particles into simple ones. These simple particles 

can be easily absorbed by the blood and thus transported to all the cells of the 

body.

Question 5: 

How is the small intestine designed to absorb digested food?

Answer :

The small intestine has millions of tiny finger-like projections called villi. These 

villi increase the surface area for food absorption. Within these villi, many blood 

vessels are present that absorb the digested food and carry it to the blood stream. 

From the blood stream, the absorbed food is delivered to each and every cell of 

the body

Page : 105

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

Answer:
The water has oxygen dissolved in it. On the other hand, the air has oxygen gas present freely. Beside this, the concentration of oxygen is more in the atmosphere than water. Hence, the aquatic organisms have to breathe quite fast to get the required oxygen. The terrestrial animals can easily get oxygen from the atmosphere.

Question2 . 
What are the different ways in which glucose is oxidised to provide energy in various organisms?

Answer:
 Glucose is oxidised either aerobically, i.e. in the presence of oxygen or anareobically, i.e. in the absence of oxygen to provide energy in various living organisms. In organisms like yeast, glucose is oxidised anareobically to give ethanol, carbon dioxide and energy. Aerobically, glucose is oxidised to give carbon dioxide, water and energy.

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

Answer:
Oxygen and carbon dioxide are transported in human beings with the help of ‘transportation system’.

Transport of oxygen: The air present in the alveolar sacs have high concentration of oxygen, while the blood capillaries surrounding the alveolar sacs are deficient in oxygen. Oxygen diffuses from the alveoli to the blood capillaries where it combines with the haemoglobin to form oxyhaemoglobin. Then the blood reaches the tissues where oxyhaemoglobin breaks into haemoglobin and oxygen. This oxygen enters the cells.

Transport of carbon dioxide: The tissues have high concentration of carbon dioxide than the blood entering them. Therefore, carbon dioxide diffuses from the tissues into the blood. Then it reaches the lungs where it diffuses into the alveoli, and expelled out into the atmosphere through the respiratory tract.

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

Answer:
 The lungs have special air sacs called ‘alveoli’. The presence of air sac increases the surface area inside the lungs. Alveoli are the places where exchange of gases takes place. There are about 300-350 millions of alveoli in each lung. The alveoli are filled with air and they swell up. During inspiration, the ribs move up and diaphragm flattens which increases the surface area. The increased surface area helps in maximum exchange of gases to take place.

Page : 110

Question1 .
 What are the components of the transport system in human beings? What are the functions of these components?

Answer:
The components along with functions of transport system in human beings are as:

Heart: It is a muscular pumping organ that helps to pump blood around the body.

Blood: The blood is a fluid connective tissue. It consists of a watery fluid called plasma, and three types of cells: red blood cells, white blood cells and platelets. Plasma helps in transporting food, carbon dioxide, salts and nitrogenous wastes in dissolved form. Red blood cells carry oxygen. White blood cells engulf bacteria and produce antibodies, which provide immunity against various disease-causing pathogens. Platelets help to clot the blood at the site of injury.

Blood vessels: There are three types of blood vessels. They are: arteries, veins and
capillaries. These vessels help in transporting the blood in the body.

Lymph: It carries digested and absorbed fats from intestine and transports them to the blood. It also drains excess fluid from extra-cellular space back into the blood.

Question 2: 
Why is it necessary to separate oxygenated and deoxygenated blood in mammals 

and birds?

Answer :

Warm-blooded animals such as birds and mammals maintain a constant body 

temperature by cooling themselves when they are in a hotter environment and by 

warming their bodies when they are in a cooler environment. Hence, these 

animals require more oxygen (O2) for more cellular respiration so that they can 

produce more energy to maintain their body temperature.

Thus, it is necessary for them to separate oxygenated and de-oxygenated blood, 

so that their circulatory system is more efficient and can maintain their constant 

body temperature.

Question . How are water and minerals transported in plants?

Answer:- Water and minerals are transported in plants through the xylem tissues, which consist of interconnected vessels and tracheids stretching from the roots to the leaves. Root hairs are in contact to the soil containing water and mineral salts. They take up mineral ions by active transport. This creates a difference in concentration of these ions between the root and soil. Therefore, water moves into the root hairs to eliminate this difference. Then water diffuses into the cortical cells. After that the water (containing dissolved minerals) reaches the endodermis by osmosis and then into the root xylem. From the root xylem the water reaches the stem xylem and then conducted to other parts through the branched xylem tissues.

The pressure with which water is pushed into the xylem of the root is called root pressure.

This pressure cannot make up for the water lost by transpiration in tall trees. The loss of water due to transpiration creates a force called transpiration pull which pulls water up through the xylem vessels to the highest point of the plant body.

Question . How is food transported in plants?

Answer:- The food is transported in plants both in ‘ upward and downward direction through

phloem tissues, which consist of sieve tubes and companion cells. The translocation in

phloem occurs with the expenditure of energy. Sucrose is the main form of carbohydrate which is transferred into the phloem tissues using energy from ATP. When sucrose is synthesised in the leaf cells, the osmotic pressure of the cells increases causing water to move into it. This causes translocation of sucrose in the form of solution from the point of synthesis to the points having less pressure. This allows the phloem to move material according to the plants needs.

Question . Describe the structure and functioning of nephrons.

Answer:- The nephron is the basic filtering unit of kidneys. Each kidney has 1-1.5 million nephrons in it.

The filtration of blood takes place in Bowman’s capsule under a very high pressure. Finally, the waste products go to a network of collecting tubules which finally meet in a common collecting duct. This collecting duct joins the ureter which carries urine to the urinary bladder for excretion.

Structure and functioning of nephrons

• Bowman’s capsule: The Bowman’s Capsule is a cup-shaped structure which houses the ‘glomerulus’. For this reason, it is also known as the ‘glomerular capsule’. Fluids flowing through the glomerulus are removed from larger particles.
• Proximal convoluted tubule or proximal tubule: This is the first twisted region after the Bowman’s capsule. It lies in the cortex. The reabsorption of essential substances takes place here. This is known as tubular reabsorption.
• Loop of Henle: The long, hairpin loop after the proximal tubule is called ‘loop of Henle’. It is extended from the cortex down into the medulla and back.
• Distal convoluted tubule or distal tubule: This is the second twisted portion of the nephron after the loop of Henle. It is located in the cortex.
• Collecting duct: This is the long straight portion after the distal tubule. The distal convoluted tubule is the most distal (distant) portion of the nephron and is responsible for the reabsorption of sodium, and water.

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

Answer.

1. Plants get rid of the oxygen produced during photosynthesis by its diffusion through stomata and lenticels.
2.  They get rid of excess water by transpiration.
3.  Many waste products are stored in cell vacuoles.
4.  Some wastes are removed in the falling leaves.
5.  Other, wastes are stored as resins and gums, especially in old xylem.
6.  Plants also get rid of some waste products by excreting into the surrounding soil.