NCERT Solutions for Class 10 Biology Chapter 6 : Life Processes

Q: Question 1. What are the criteria for determining whether something is alive?

Answer. Walking, breathing, and other apparent changes can all be used to assess whether or not something is alive. However, some living objects will undergo changes that are not visible to the naked sight; thus, the presence of a living process is a key criterion for determining whether or not something is alive.

Q: Question 2. How are human lungs designed to maximise the area available for gas exchange?

Answer. The lungs are an essential component of the human body. The pathway inside the lungs is divided into smaller and smaller tubes, which eventually finish in alveoli, which are balloon-like structures. The alveoli provide a surface where gases can exchange. The alveolar walls usually contain a vast network of blood vessels. When we breathe in, our ribs lift, our diaphragm flattens, and our chest cavity expands. As a result of this process, the air is pulled into the lungs and fills the enlarged alveoli. The blood transports carbon dioxide from the rest of the body to the alveoli, while the oxygen in the alveolar air is taken up by the blood in the alveolar blood vessels and transmitted to all other body cells. The lungs always contain a residual volume of air during the normal breathing cycle, when air is taken in and released out so that oxygen can be absorbed and carbon dioxide can be released.

Question 1

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

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Human beings are multicellular organisms having a complex body structure. The oxygen requirement in multicellular organisms cannot be met by diffusion because-
1) Diffusion is a slow process.

2) In multicellular organisms, the cells are not in direct contact with the outside environment as in unicellular organisms.

Therefore, in human beings, there are specialized tissues and organs that help to meet the oxygen requirements of the body.

Answer

Human beings are multicellular organisms having a complex body structure. The oxygen requirement in multicellular organisms cannot be met by diffusion because-
1) Diffusion is a slow process.

2) In multicellular organisms, the cells are not in direct contact with the outside environment as in unicellular organisms.

Therefore, in human beings, there are specialized tissues and organs that help to meet the oxygen requirements of the body.

Question 2

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

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All the living organism is made up of cell and shows living characteristics by showing some visible movement such as walking, breathing, or growing. However, a living organism can also have movements, which are not visible to the naked eye.
But all the living cells perform life processes like respiration, nutrition, reproduction, etc. Therefore, the presence of life processes is a fundamental criterion that can be used to decide whether something is alive or not.

Answer

All the living organism is made up of cell and shows living characteristics by showing some visible movement such as walking, breathing, or growing. However, a living organism can also have movements, which are not visible to the naked eye.
But all the living cells perform life processes like respiration, nutrition, reproduction, etc. Therefore, the presence of life processes is a fundamental criterion that can be used to decide whether something is alive or not.

Question 3

What are outside raw materials used by an organism?

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All the organism depends on the environment for their needs. The raw material required by any organism varies with the complexity of the organism and its environment. Various outside raw materials used by an organism to perform life process are as follows:
Food like plants and other animals as a source of supplying energy and materials.
Oxygen for the breakdown of food to obtain energy.
Water for proper digestion of food and other functions inside the body.

Answer

All the organism depends on the environment for their needs. The raw material required by any organism varies with the complexity of the organism and its environment. Various outside raw materials used by an organism to perform life process are as follows:
Food like plants and other animals as a source of supplying energy and materials.
Oxygen for the breakdown of food to obtain energy.
Water for proper digestion of food and other functions inside the body.

Question 4

Which processes would you consider essential for maintaining life?

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Answer:

Life processes are processes which are required to maintain body functions and are necessary for survival.

There are the 7 processes all living things do - movement, reproduction, sensitivity, nutrition, excretion, respiration and growth.

Answer

Answer:

Life processes are processes which are required to maintain body functions and are necessary for survival.

There are the 7 processes all living things do - movement, reproduction, sensitivity, nutrition, excretion, respiration and growth.

Question 5

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

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Answer:

Fat digestion takes place in the small intestine.
The alkaline secretion of the liver, bile, is carried to the small intestine by the bile duct.
The process starts with emulsification (break down) of large fat globules by the salt of bile into smaller micelles to facilitate further enzymatic reaction and digestion process.
The fat-digesting lipase enzyme in pancreatic juice and intestinal juices digest the fat in micelles into triacylglycerols and then fatty acids and glycerol.
These fat digestion products are then absorbed by the intestinal mucosa and are carried to tissues by the lymphatic system and blood where they either serve as energy fuel or are stored after re-esterification.

Answer

Answer:

Fat digestion takes place in the small intestine.
The alkaline secretion of the liver, bile, is carried to the small intestine by the bile duct.
The process starts with emulsification (break down) of large fat globules by the salt of bile into smaller micelles to facilitate further enzymatic reaction and digestion process.
The fat-digesting lipase enzyme in pancreatic juice and intestinal juices digest the fat in micelles into triacylglycerols and then fatty acids and glycerol.
These fat digestion products are then absorbed by the intestinal mucosa and are carried to tissues by the lymphatic system and blood where they either serve as energy fuel or are stored after re-esterification.

Question 6

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

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Answer-

Salivary glands are present in the oral cavity that secrete saliva which is released into the mouth.
Saliva contains bicarbonate and salivary amylase and serves to initiate the process of starch digestion into simple sugars by breaking the $α$ -1, 4- glycosidic linkage of starch to release oligosaccharides.

Answer

Answer-

Salivary glands are present in the oral cavity that secrete saliva which is released into the mouth.
Saliva contains bicarbonate and salivary amylase and serves to initiate the process of starch digestion into simple sugars by breaking the $α$ -1, 4- glycosidic linkage of starch to release oligosaccharides.

Question 7

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

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Answer-

A) Necessary conditions required for autotrophic nutrition are:

1. Carbon dioxide

2. Water

3. Chlorophyll pigment

4. Sunlight

B) Byproducts are:

1. Oxygen
2. Carbohydrates (glucose)

Autotrophic organisms are self-feeders that can synthesise their own food.

Green plants are photoautotrophs that can carry out photosynthesis.

Photosynthesis is a process in which atmospheric carbon dioxide is fixed and combined with water to form glucose and oxygen.

Photosynthesis always takes place in the presence of sunlight which is captured by chlorophyll pigment present in plants.

The equation for photosynthesis is

6 C O_{2} + 6 H_{2} O ⟶ C_{6} H_{12} O_{6} + 6 O_{2}

Answer

Answer-

A) Necessary conditions required for autotrophic nutrition are:

1. Carbon dioxide

2. Water

3. Chlorophyll pigment

4. Sunlight

B) Byproducts are:

1. Oxygen
2. Carbohydrates (glucose)

Autotrophic organisms are self-feeders that can synthesise their own food.

Green plants are photoautotrophs that can carry out photosynthesis.

Photosynthesis is a process in which atmospheric carbon dioxide is fixed and combined with water to form glucose and oxygen.

Photosynthesis always takes place in the presence of sunlight which is captured by chlorophyll pigment present in plants.

The equation for photosynthesis is

6 C O_{2} + 6 H_{2} O ⟶ C_{6} H_{12} O_{6} + 6 O_{2}

Question 8

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

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The difference between aerobic and anaerobic respiration.

Aerobic respiration	Anaerobic respiration
1. Aerobic respiration refers to complete breakdown of metabolic fuels in presence of oxygen.	1. Anaerobic respiration is the process of partial breakdown of fuel (glucose) in absence of oxygen.
2. It includes glycolysis, citric acid cycle and oxidative phosphorylation. The first two processes take place in the cytoplasm while last one occurs in mitochondria.	2. Glycolysis is followed by ethanol fermentation (occurs in yeast) or lactic acid fermentation (in muscles and microbes like lactic acid bacteria).
3. The end products are carbon dioxide and water.	3. End products of ethanol fermentation are ethanol and carbon dioxide; that of lactic acid fermentation are lactic acid
4. Owing to complete oxidation of glucose, a large amount of energy is produced (36-38 ATP molecules)	4. Incomplete oxidation of glucose does not release all stored energy and only 2 ATP molecules are produced.

Anaerobic respiration is carried out by yeast and other anaerobic organisms like lactic acid bacteria, E. coli, Staphylococcus, Clostridium etc.

Answer

The difference between aerobic and anaerobic respiration.

Aerobic respiration	Anaerobic respiration
1. Aerobic respiration refers to complete breakdown of metabolic fuels in presence of oxygen.	1. Anaerobic respiration is the process of partial breakdown of fuel (glucose) in absence of oxygen.
2. It includes glycolysis, citric acid cycle and oxidative phosphorylation. The first two processes take place in the cytoplasm while last one occurs in mitochondria.	2. Glycolysis is followed by ethanol fermentation (occurs in yeast) or lactic acid fermentation (in muscles and microbes like lactic acid bacteria).
3. The end products are carbon dioxide and water.	3. End products of ethanol fermentation are ethanol and carbon dioxide; that of lactic acid fermentation are lactic acid
4. Owing to complete oxidation of glucose, a large amount of energy is produced (36-38 ATP molecules)	4. Incomplete oxidation of glucose does not release all stored energy and only 2 ATP molecules are produced.

Anaerobic respiration is carried out by yeast and other anaerobic organisms like lactic acid bacteria, E. coli, Staphylococcus, Clostridium etc.

Question 9

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

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Alveoli are pouch-like air sac that is made up of simple squamous epithelium. It has a thin cell wall to facilitate gaseous exchange.
The presence of millions of alveoli in the lungs provides ample surface area to facilitate gaseous exchange between the air in alveoli and blood in surrounding capillaries.
Oxygen diffuses across the alveolar and capillary wall into the bloodstream while carbon dioxide diffuses from blood across the mentioned walls into the alveoli.

Answer

Alveoli are pouch-like air sac that is made up of simple squamous epithelium. It has a thin cell wall to facilitate gaseous exchange.
The presence of millions of alveoli in the lungs provides ample surface area to facilitate gaseous exchange between the air in alveoli and blood in surrounding capillaries.
Oxygen diffuses across the alveolar and capillary wall into the bloodstream while carbon dioxide diffuses from blood across the mentioned walls into the alveoli.

Question 10

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

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Haemoglobin molecule contains four polypeptide chains and four heme prosthetic groups. It serves as carrier of oxygen gas. Haemoglobin deficiency would decrease the oxygen carrying capacity of blood which in turn would cause breathing problems and lack of energy and weight loss.

Answer

Haemoglobin molecule contains four polypeptide chains and four heme prosthetic groups. It serves as carrier of oxygen gas. Haemoglobin deficiency would decrease the oxygen carrying capacity of blood which in turn would cause breathing problems and lack of energy and weight loss.

NCERT Solutions for Class 10 Biology Chapter 6 : Life Processes

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