NCERT solution of class 10 chapter life process

NCERT solution of class 10 chapter life process
Life process
page no. 95
1. Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
Ans: Unlike the unicellular organisms, the multi-cellular organisms have complex body structures with specialized cells and tissues to perform various necessary functions of the body. Since these cells are not in direct contact with surrounding environment so, simple diffusion connot meet the oxygen requirement of all these cells.
2.What criteria do we use to decide whether something is alive?
Ans: Any visible movement such as walking, breathing or growing is generally used to decide whether something is alive or not.
3. What are outside raw materials used for by an organism?
Ans: Various outside raw materials used by an organism are as follows:

Food as source of supplying energy and materials.
Oxygen for breakdown of food to obtain energy.
Water for proper digestion of food and other functions inside the body.

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

Ans: Life processes such as nutrition,respiration, transportation, excretion, etc are essential for maintaining life.

Page no. 101

1.What are the difference between autotropic nutrition and heterotropic nutrition?

Ans:

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

Ans: The following raw materials are required for photosynthesis:

Carbon dioxide: Plants get CO2 from atmosphere through stomata.
Water: Plants absorb water from soil through roots and transport to leaves.
Sunlight: Sunlight, which is absorbed by the chlorophyll and other green parts of the plant.

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

Ans: Following are the roles of acid in our stomach:-

It kills many bacteria and other microorganisms that enter alongwith the food.
It creates an acidic medium. In this acidic medium, enzyme pepsinogen is converted to pepsin, which is a protein-digesting enzyme.

4. What is the function of digestive enzymes?

Ans:

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.

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

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

Function: These villi increase the surface area for more efficient food absorption.

Within these villi, many blood vessels are present that absorbed the digested food and carry it to the bloodstream. From the bloodstream, the absorbed food is delivered to each and every cell of the body.

Page no. 105

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

Ans: Terrestrial organisms take up oxygen from the atmosphere whereas aquatic animals obtain oxygen from water. Air contains more O2 as compared to water. Since the content of O2 in air is high, the terrestrial animals do not have to breathe faster to get more oxygen. Therefore, unlike aquatic animals, terrestrial animals do not neend adaptations for gaseous exchange.

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

Ans

Anaerobic Respiration:

This process takes place in absence of oxygen.
Example : In yeast during fermentation.
In this case, pyruvate is converted into ethanol and carbon dioxide

Aerobic Respiration:

This process takes place in presence of oxygen.
The release of energy in aerobic respiration is much more than anaerobic respiration.

Lack of Oxygen:

Sometimes, when there is lack of oxygen, especially during vigorous activity, in our muscles, pyruvate is converted into lactic acid.
Formation of lactic acid in muscle causes cramp.

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

Ans: Transport of Oxygen:

The respiratory pigments (haemoglobin) present in red blood cells takes up the oxygen from the air to tissues which are deficient in oxygen.

Transport of carbon dioxide:

Carbon dioxide is more soluble in water hence, it is mostly transported from body tissue in the dissolved from in our blood plasma to lungs where it diffuses from blood to air in the lungs and then expelled out through nostrils.

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

Ans: In the lungs the bronchioles terminate in balloon like structure called alveoli.the alveoli are very thin membrane contains network of blood cappilaries that increase the surface area for exchange of gases.

Page no.110

1. What are the components of the transport system in human being? What are the function of these components?

Ans:

The main components of the transport system in human beings are the heart, blood, and blood vessels.
Heart pumps oxygenated blood throughout the body. It receives deoxygenated blood from the various body parts and sends this impure blood to the lungs for oxygenation.

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

Ans:

It is necessary to separate oxygenated and doxygenated blood to maintain efficient supply of oxygen into the body.
This system is essential in animals that have high energy need.
For example, animals like mammals and birds which constantly use this energy to maintain their body temperature.

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

Ans: In highly organised plants, there are two different types of conducting tissues- xylem and phloem.

Xylem: Xylem conducts water and minerals obtained from the soil to the rest of the plant.

Phloem: Phloem transports food materials from the leaves to different parts of the plant body.

4. How are water and minerals transported in plants?

Ans:

Water and minerals are transported through xylem cells from soil to the leaves.
The xylem cells of roots stem and leaves are interconnected to form a conducting channel that reaches all parts of the plant.
The root cells take ions from the soil. This creates a difference between the concentration of ions of roots and soil.
Therefore, there is a steady movement of water into xylem. An osmotic pressure is formed and water and minerals are transported from one cell to the other cell due to osmosis. The continuous loss of water takes place due to transpiration.
Transpiration creates a suction pressure, as a result of which water is forced into the xylem cells of roots.

5. How is food transported in plants ?

Ans: phloem transports food materials from the leaves to diffrent parts of the plants the transportation

of food in phloem is achieved by utilizing energy from ATP which healps in creating osmotic preasure that transport food from the area of high concentration to low concentration

page no 112

1 Describe the structure and functioning of nephrons ?

Ans Nephrons are the basic filtering units of kidneys Each kidney possesses large number of nephrons approximately 1-1.5 millions. The main components of the naphron are glomerulus, Bowman"s capsule, and a long renal tublue.

functioning of a nephron:

Functioning of a nephron:

The blood enters the kidney through the renal artery, which branches into many capillaries associated with glomerulus.
The water and solutes are transferred to the nephron at Bowman"s capsule
In the proximal tubule, some substances such as amino acids, glucose, and salts are selectively reabsorbed and unwanted molecules are added in the urin
The filtrate then moves down into the loop of Henle, where more water is absorbed.
From here the filtrate moves upwords into the distal tubule and finally to the collecting duct.collecting duct collects urine from many nephron
The urine formed in each kidney enters a long tube called ureter. From ureter it gets transported to the urinary bladder and then into the urether.

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

Ans.Plants can get rid of excess of water by transpriation. Waste materials may be stored in the cell vacuoles or as gum and resin, especially in old xylem. It is also stroed in the leaves that later fall off.

3. How is the amount of urine produced regulated ?

Ans. The amount of urine produced depends of the amount of excess water and dissloved wastes present in the body. some other factors such as habitat of an organism and hormone such as Anti-diuretic hormone [ADH] also regulates the amount of urine produced.

page No 113

Excercise

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

[a] nutrition.

[b] respiration.

[c] excretion.

[d] transportation.

Ans. [c] excretion.

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.

Ans[a] transport of water.

3. The autotropic mode of nutrition requires.

[a] carbon dioxide and water.

[b] chlorophyll.

[c] sunlight.

[d] all of the above.

Ans. [d] all of the above.

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

[a] cytoplasm.

[b] mitochondria.

[c] chloroplast.

[d] nucleus.

Ans. [b] mitochondria.

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

Ans:

Fats are present in the form of large globules in the small intestine.The small intestine receives the secreations. from the liver and the pancrease.
The bile salts(from the liver) break down the large fat globules into smaller globules so that the pancreatic enzyme lipase can easily act on them.
This is referred to as emulsification of fats.
This process takes place in the small intestine.

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

Ans: The role of saliva in the digestion of food.

It moistens the food for easy swallowing.
It contains a digestive enzyme called salivary amylase, which breaks down starch into sugar.
It kills the bacteria.

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

Ans: Autotrophic nutrition takes place through the process of photosynthesis. Carbon dioxide.water,chlorophyll pigment, and sunlight are the necessary conditions required for autotrophic nutrition.

Starch and oxygen are the by-product of photosynthesis.

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

Ans:

Lower organisms such as bacteria and yeast use anaerobic respiration.

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

Ans:

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. I
t can also lead to disease called anaemia.

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

Ans: During a single cycle blood goes twice in the heart which is known as double circulation. It is necessary in human being to separate oxygenated and deoxygenated blood because this makes their circulatory system is more efficient and helps in maintaing constant body temperature.

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

Ans: