MG SCHOOL EDUCATION: 10th Life procs prvs yers qns

Class 10 Science

Chapter 6 Life Processes

Previous Years Appeared Questions

MULTIPLE CHOICE QUESTIONS

1. The correct statement related to digestion in small intestine is (june 2019)

(A) acidic food is made alkaline by bile juice

(B) food is made acidic by hydrochloric acid

(D) protein is digested due to the action of pepsin.

Ans: (A) acidic food is made alkaline by bile juice

2. The blood vessels that carry blood from all parts of the human body to the heart are (July 2021)

(A) arteries (B) capillaries

Ans: (D) veins

3. The site of complete digestion of carbohydrates, proteins and fats is (Sep 2020)

(A) stomach (B) large intestine

Ans: (C) small intestine

4. Plants can get rid of excess of water by this process (July 2021)

(A) Transpiration (B) Photosynthesis

Ans: (A) Transpiration

5. The blood vessels that carry deoxygenated blood from the heart to the lungs in the human body are (Sep 2021)

(A) Pulmonary veins (B) Aorta

Ans: (D) Pulmonary arteries

6. The transport of soluble products of photosynthesis in plants is (Sep 2021)

(A) Transpiration (B) Osmosis

Ans: (D) Translocation

1. In plants the major function of xylem is the transportation of- (June 2022)

(A) water (B) food

Ans: (A) water

ONE MARKS QUESTIONS

1. Under what condition lactic acid is produced in the muscle cells ? (April 2019)

Ans. : Lactic acid is produced when there is lack of oxygen in the muscle cells.

2. Name the products of anaerobic respiration. (June 2019)

Ans : Ethanol and Carbon dioxide are the products of anaerobic respiration

3. Draw the diagram showing opened stomata. Label the following parts : (i) Guard cells (ii) Stomatal pore. (June 2019)

Ans:

4. The rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms, Why ? (April 2020)

Ans : Aquatic organisms like fishes obtain oxygen from water present in dissolved state through their gills. Since the amount of dissolved oxygen is fairly low as compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms.

5. Eating chapatti by chewing it very slowly tastes sweeter. Why ?(Sep 2020)

Ans. :

★When chapatti is chewed for some time it taste sweeter because, the saliva produced by the salivary glands consist of enzyme called Amylase .

★ This enzyme converts the starch content(carbohydrate)present in the chapatti into sugar.

TWO MARKS QUESTIONS

1. Explain the process of translocation of food materials in plants. (April 2019)

Ans. :

★ Translocation of food materials occurs in the phloem tissue of plants.

★ This process takes place in the sieve tubes with the help of adjacent companion cells both in upward and downward directions.

★ This process is achieved by osmotic pressure.

2. Explain the process of digestion in the small intestine of man. (April 2019)

Ans. :

★ Small intestine is the site of complete digestion of proteins, carbohydrates and fats.

★ Enzymes in the intestinal juice convert proteins into amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.

★ Digested food is absorbed by the villi present in the walls of intestine.

3. Diagrams given below represent hearts of three different animals. Observe it and answer the question.

Among these, which heart is helpful to the animals that require more energy ? Why ? (June 2019)

Ans:

★ Heart - 2

★ Oxygenated and deoxygenated blood will not mix together Efficient supply of oxygen to the body. Helpful to maintain body temperature.

4. The approximate lengths of small intestine of animals x and y are given in the table. Observe it and answer the question.

Identify the herbivorous and carnivorous animals in the table and support your decision with scientific reasons. (June 2019)

Ans :

★ Animal X is herbivorous and animal Y is carnivorous.

★The small intestine is longer in herbivores than in carnivores because herbivores consume plant which is full of cellulose and the digestion of cellulose takes a long time. Herbivores need a longer small intestine to allow cellulose to be digested.

★ Whereas Meat is easier to digest, hence carnivores have shorter small intestine.

5. The body temperature of frogs and lizards depend on temperature in the environment, Justify. (April 2020)

Ans. :

★Both frogs and lizards have three chambered heart

★ Oxygenated and deoxygenated blood mix in the heart.

★ Production of energy became slightly less. This energy cannot be used for maintaining constant temperature.

6. Give reason :

a) Ventricles of the human heart have thick wall.‘

b) It is necessary to separate oxygenated and deoxygenated blood in mammals and birds.‘ (April 2022)

Ans. :

a) Since ventricles have to pump blood into various organs.

b) Since they need more energy to maintain their body temperature constant.

7. Draw the diagram showing the structure of human excretory system and label ureter‘. (June 2022)

Ans:

8. Observe the given below figures :

a) Which figure indicates the massive amount of exchange of gases ? Why ?

b) Name the parts X and Y. What is the function of other part X? (April 2023)

Ans. :

★ Fig. (i) / Open stomata

★ It is because the stomatal pore is open.

X — Guard cell

Y — Stomatal pore

Regulates opening and closing of stomatal pore.

THREE MARKS QUESTIONS

1. Draw the diagram showing the sectional view of the human heart. Label the following parts. (i) Aorta (ii) Chamber of heart that receives deoxygenated blood. (April 2019)

Ans:

2. How are the functions of arteries, veins and capillaries are interrelated in the circulation of blood ? (Sep 2020)

Ans. :

★ Arteries carry blood away from the heart to various organs of the body. On reaching an organ or tissue, the artery divides into smaller and smaller vessels to bring the blood in contact with all the individual cells.

★ Exchange of material between the blood and surrounding takes place across the thin wall of smallest vessels, the capillaries. The capillaries then join together to form veins.

★ Veins convey the blood away from the organ or tissue. Veins collect the blood from different organs and bring it back to the heart.

3. How does transportation of water take place over the heights in a plant ? (Sep 2010)

Ans :

★ At the roots, cells in contact with the soil actively take up ions. This creates a difference in the concentration of these ions between the root and the soil.

★ Water moves into the root from the soil to eliminate this difference. There is a steady movement of water into root xylem, creating a column of water that is steadily pushed upwards.

★ Evaporation of water molecules from the stomata of leaves due to transpiration creates a suction which pulls water from xylem cells of root.

4. Explain the role of small intestine in the human digestive. (State level Preparatory 2023)

Ans:

★ Small intestine is the site of complete digestion of proteins, carbohydrates and fats.

★ Enzymes in the intestinal juice convert proteins into amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.

★ Digested food is absorbed by the villi present in the walls of intestine.

5. Explain the role of „nose‟ and alveoli in the human respiratory system. . (State level preparatory 2023)

Ans:

★ nostrils act as the body’s first line of defence against foreign pathogens. they provide additional humidity for inhaled air.

★ The alveoli contain network of blood capillaries that increase the surface area for exchange of gases.

★ The inhaled oxygen diffuses into the pulmonary capillaries. The carbon dioxide from the blood diffuses into the alveoli and is expelled through exhalation.

FOUR MARKS QUESTIONS

1. Which molecule is formed during the first step of cellular respiration by the breakdown of glucose molecule in cytoplasm ? Mention the types of respiration and write any two differences between them. (April 2022)

Ans. : ★ Pyruvate.

★ Two types : i) Aerobic respiration ii) Anaerobic respiration

2. Which are the factors essential for photosynthesis ? Mention the events that occur during this process and represent this process by balanced chemical equation. (April 2022)

Ans:

★ Factors essential for photosynthesis : Carbon dioxide, water, minerals, sunlight and chlorophyll.

★Events that occur during photosynthesis : i) Absorption of light energy by chlorophyll.

ii) Conversion of light energy into chemical energy.

iii) Splitting of water molecules into hydrogen and oxygen molecules.

iv) Reduction of carbon dioxide into carbohydrates.

★ Equation :

3. Explain the stages of double circulation‘ of the blood in humans. (June 2022)

Ans. :

Transportation of blood in heart :

i) Oxygen-rich blood from the lungs comes to the left atrium.

ii) When the left atrium relaxes and contracts then blood gets transferred to left ventricle

iii) When the left ventricle contracts the blood is pumped out to the body through aorta.

iv) De-oxygenated blood comes from the body to the right atrium.

v) As the right atrium contracts the blood get transferred to the right ventricle.

vi) On contraction of right ventricle the blood go to the lungs for oxygenation.

4. Mention the events that occur during photosynthesis in plants. What are the methods used by plants to get rid of excretory products ? (June 2022)

Ans:

Events that occur during photosynthesis: ★ Absorption of sunlight by chlorophyll.

★ Conversion of light energy into chemical energy / decomposition of water into oxygen and hydrogen molecule.

★ Reduction of carbon dioxide into carbohydrate.

Methods to get rid of excretory products in plants :

★ Excess of water removed by transpiration

★ Remove oxygen and carbon dioxide gases through stomata

★ Waste products and dead cells in vacuoles by shedding leaves / barks

★ Resins and gums get store in old xylem

★ Diffusing certain wastes into surrounding soil.

5. a) What is the important function of 'villi' and 'alveoli' in our body?

b) Explain the structure and function of nephron. (KSEEB MQP 22-23)

Ans :

★ The small intestine has millions of tiny finger-like projections called villi. These villi increase the surface area for more efficient food absorption.

★ Each lung contains large number of alveoli which increase the surface area for gaseous exchange making the process of respiration more efficient.

The main components of the nephron are glomerulus, Bowman’s capsule, and a long renal tubule.

Functioning of a nephron:

The blood enters the kidney through the renal artery,

★ Waste materials in the blood are filtered and collected by Bowman’s capsule.

★ Some substances in the initial filtrate, such as glucose, amino acids, salts and a major amount of water, are selectively re-absorbed as the urine flows along the tube.

★ The urine forming in each kidney eventually enters a long tube, the ureter, which connects the kidneys with the urinary bladder.

6. a) What is the importance of transpiration in plants?

b) How does translocation of materials take place by phloem tissue?

Ans :

a) Transpiration helps in the absorption and upward movement of water and minerals. And helps in temperature regulation.

b) Phloem transports food materials from the leaves to different parts of the plant body. The transportation of food in phloem is achieved by utilizing energy from ATP. The translocation of food and other substances takes place in the sieve tubes with the help of adjacent companion cells both in upward and downward directions.

7. Explain the digestion of food materials in stomach and small intestine. (April 2023)

Ans. :

Stomach :

★ Gastric glands present in the wall of the stomach release hydrochloric acid, pepsin and mucus.

★ Hydrochloric acid creates an acidic medium which facilitates the action of pepsin.

★ Pepsin digests protein.

Small intestine :

★ It receives pancreatic juice and bile juice. Bile juice makes the food alkaline.

★ Bile salts emulsify the fats in the small intestine.

★ Trypsin present in pancreatic juice helps to digest the proteins.

★ Lypase breaks down the emulsified fats.

★ Enzymes present in the small intestinal juice convert proteins into amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.

8. Explain the role of xylem and phloem tissues in the transportation of materials in plants. (April 2023)

Ans:

Xylem : Water conducting tissue.

★ In xylem tissue, vessels and tracheids of the roots, stem and leaves are interconnected to form a continuous system of water-conducting channel reaching all parts of the plant.

★ Transpiration ( loss of water through stomata ) creates suction pressure and creates a column of water.

★ This steadily pushes the water upward with dissolved minerals in it.

Phloem : Food conducting tissue.

★ Phloem translocates soluble products of photosynthesis, amino acids and other substances from the leaves to storage organs of roots, fruits and seeds, and to the growing organs.

★ Translocation takes place in sieve tube with the help of companion cell, both in upward and downward directions.

9. a) Compare the functions of xylem tissue with that of phloem tissue.

b) Explain the process of exchange of gases that take place through stomata in plants. (June 2023)

Ans: a)

★ In plants the large intercellular spaces and all the cells are oftenly in contact with air, due to this CO2 and oxygen are exchanged by diffusion here. This means

★ Gases can go into cells and away from them and out into the air / atmosphere.

10. a) How is the structure of human heart supportive in transporting oxygenated blood and deoxygenated blood ? Explain. b) In humans, how is the digested food absorbed by the blood ? Mention the function of blood in transporting necessary materials. (June 2023)

Ans:

Human heart

★ Has different chambers

★ The valves present in between the chambers prevent backward flow of blood

★ Separated by dividing wall septum

★Septum is responsible for creating separate pathways to transport oxygenated and deoxygenated blood.

Absorbed by finger like projections Villi present in small intestine

★ Blood plasma — transports food, carbon dioxide and nitrogne wastes

★ RBC — Carries oxygen

★ Many other substances like salts are also transported by blood.

IMPORTANT QUESTIONS

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

Ans : It provides acidic medium to promote the action of pepsin It kills bacteria present in the food

2. How is small intestine designed to absorb digested food ?

Ans : The small intestine has millions of tiny finger-like projections called villi. These villi increase the surface area for more efficient food absorption. Within these villi, many blood vessels are present that absorb the digested food and carry it to the bloodstream.

3. Write the equation for the process of breakdown of glucose in a cell :

(a) in the presence of oxygen.

(b) in the absence of oxygen.

Ans : (a) in the presence of oxygen.

Glucose → Piruvate → Carbon dioxide + water + Energy

(b) in the absence of oxygen.

Glucose → Piruvate → Ethanol + Carbon dioxide + Energy

4. Give reason for the following :

(a) Arteries are thick walled blood vessels.

(b) Veins have valves in them.

Ans :

(a) Arteries are thick walled blood vessels because, the blood emerges from the heart under high pressure.

(b) Veins have valves in them because , to ensure that the blood flows only in one direction.

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

Ans : The transport system in human beings mainly consists of heart, blood and blood vessels.

(i) Function of heart : The heart receives deoxygenated blood from the body parts and pumps it to lungs for enriching with oxygen. It receives purified blood from lungs and pumps it around the body.

(ii) Function of blood : Blood transports oxygen, carbon dioxide, digested food, hormones and nitrogeneous waste like urea. It also protects the body from diseases and regulates the body temperature.

(iii) Function of blood vessels : The blood pushed by the heart flows through the blood vessels (arteries, veins and capillaries) and also comes back to the heart through them.

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

What are the advantages of having four chambered heart in birds and mammals

Ans :

★Separation of oxygenated and deoxygenated blood allows good supply of oxygen to the body.

★ This system is useful in animals that have high energy requirement.

★ Mammals and birds constantly need oxygen to get energy to maintain their body temperature constant.

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

Ans : Blood goes through the heart twice during each cycle in our body. This is known as double circulation. Heart collects deoxygenated blood from body and send it to lungs for purification Heart collects oxygenated blood from lungs and supply it to all body parts . Necessity of double circulation:

★It avoids deoxygenated and oxygenated blood from mixing.

★ This type of separation of oxygenated and deoxygenated blood ensures a highly efficient supply of oxygen to the body.

★ This is useful in case of humans who constantly need energy to maintain their body temperature.

8. How arteries and veins are structurally differ in each other ?

Ans :

★ Since the blood emerges from the heart under high pressure, the arteries have thick, elastic walls.

★ Veins do not need thick walls because the blood is no longer under pressure, instead they have valves that ensure that the blood flows only in one direction.

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

Ans: Due to the deficiency of haemoglobin in blood, its oxygen carrying capacity decreases. As a result the production of energy by oxidation will become slower. Therefore, one would fall sick and would feel fatigue most of the time.

10. Describe the structure and functioning of nephrons.

Ans : Structure of nephron : Each nephron is composed of two parts.

★ First one is a cup-shaped bag at its upper end which is called Bowman‘s capsule. The Bowman‘s capsule contains a bundle of blood capillaries which is called glomerulus.

★The other part of the nephron is coiled which carries filtrate to the collecting duct

Function of nephron :

★ Filtration of blood takes place in Bowman‘s capsule from the capillaries of glomerulus. The filtrate passes into the tubular part of the nephron. This filtrate contains glucose, amino acids, urea, uric acid, salts and water.

★ As the filtrate flows along the tubule, useful substances such as glucose, amino acids, salts and water are selectively reabsorbed into the blood by capillaries surrounding the nephron tubule.

★ The filtrate which remained after reabsorption is called urine.  Urine is collected from nephrons to carry it to the ureter from where it passes into urinary bladder.

11. How is the amount of urine produced regulated?

Ans :

It depends on the quantity of excess water and wastes dissolved in water.

★ Quantity of water : When water is abundant in the body tissues, large quantities of dilute urine is excreted out. When water is less in quantity in the body tissues, a small quantity of concentrate urine is excreted.

★Quantity of dissolved wastes : Dissolved wastes, especially nitrogenous wastes, like urea and uric acid and salts are excreted from the body. When there is more quantity of dissolved wastes in the body, more quantity of water is required to excrete them. Therefore, the amount of urine produced increases.

12. Compare to animals , plants need less energy. Why ?

Ans :

★ Plant doesn‘t move

★ Major part of the plant body is made up of dead cells

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

Ans :

14. Draw the diagram showing the structure of nephron and label the parts.

Ans:

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

Ans: In lungs, the bronchioles terminate in balloon-like structures called alveoli. The alveoli contain network of blood capillaries that increase the surface area for exchange of gases.

16. Mucus is not used for churning the food or digesting it. Then why is it secreted in the stomach?

Ans: Excessive secretion of HCI can damage the inner lining of stomach. Hence, mucus is secreted in the stomach to protect its inner lining from being damaged by HCI.

17. Leaves of a healthy potted plant were coated with petroleum jelly. How will it affect the plant? State two reasons.

Ans: The plant will not remain healthy for long due to the following reasons:

1. There will be no transpiration.

2. There will be no exchange of gases which will affect the rate of photosynthesis.

18. A sample of water weed placed in water and exposed to sunlight. Bubbles of gas seen on the surface of the leaves .

(i) Name the gas evolved

(ii) Name the process taking place and

(iii) write the balanced equation of the reaction taking place

Ans:

(i) Oxygen gas evolved

(ii) photosynthesis process

(iii) 6CO2 + 6H2O → C6H12O6 + 6O2

19. Give two points of differences between respiration in plants and respiration in animals

Ans :

(i) In plants, all parts like the root, stem, leaves, etc., perform respiration individually., while in animals, either the general body surface or specific organs like the skin, gills, lungs, etc.,

(ii) There is a minimal transport of gasses from one part of the plant to other , unlike the animals

(iii) Plant respiration occurs at much slower rate than animals

20 Why the walls of trachea are supported by cartilaginous rings?

Ans: The trachea is supported by cartilaginous rings which prevent the collapsing even when there is not much air in it.