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Class 10 Science Chapter 5 Previous Year Questions - Life Processes

2023

Q1: Class 10 Science Chapter 5 Previous Year Questions - Life Processes
Ans: (b)

Q2:  Class 10 Science Chapter 5 Previous Year Questions - Life Processes
Ans:  (c) Presence of villi in small intestine increases the capacity of absorption by wall of intestine.

Question for Previous Year Questions: Life Processes
Try yourself:Q3: Water in the root enters due to                   (2023)
View Solution

Q4: As compared to terrestrial organisms, the rate of breathing in aquatic organism is

(a) faster because they need more oxygen for their survival

(b) faster because the amount of dissolved oxygen in water is fairly low

(c) slower because the amount of dissolved oxygen in water is fairly low

(d) slower because the capacity of water of dissolving atmospheric air is limited
Ans:  (b)  In aquatic organisms, rate of breathing is higher as these organisms utilise oxygen dissolved in water which is present in lesser amount compared to others.

Q5:  Observe the following diagram and identify the process and its significance from the following options:

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(a)  Evaporation : maintains water contents in leaf cells.

(b)  Transpiration : creates a suction force which pulls water inside the plant.

(c)  Excretion : helps in excreting out waste water from the plant.

(d) Translocation : helps in transporting materials from one cell to another. (2023) 

Ans:   (b) : Transpiration pull help in the upward movement of water from roots to leaves. A lot of water evaporates through stomata present on the surface of leaf.

Q6:  The process in which loss of water in the form of vapours from the aerial parts of plants takes place is X, which helps in Y. Here, X and Y respectively are
(a) transpiration and photosynthesis
(b) transpiration and temperature regulation
(c)  translocation and movement of soluble products of photosynthesis in phloem
(d) translocation and absorption of water and minerals from soil by roots. (2023)

Ans: (B)

Q7:  Assertion (A) : The walls of atria are thicker than those of the ventricles.

         Reason (R) : Ventricles have to pump blood into various organs at high pressure.

(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A)

(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A)

(c) Assertion (A) is true, but Reason (R) is false.

(d) Assertion (A) is false, but Reason (R) is true. (2023) 
Ans:  (d) The walls of ventricles are thicker than walls of atria.

Q8: Two green plants are kept separately in oxygen-free containers, one in the dark and the other in sunlight. It was observed that plants kept in the dark could not survive longer. Give a reason for this observation. (2023)
Ans:
The plant kept in the dark could not survive longer because it will not be able to produce the oxygen required for its respiration by the process of photosynthesis. Oxygen is evolved as the byproduct of photosynthesis during the photolysis of water and helps plants to survive longer than is kept in sunlight.

Q9: List the events that take place during the process of photosynthesis in the proper sequence. (2023)
Ans: The three events that occur during the process of photosynthesis are;
(i) Absorption of light energy by chlorophyll.
(ii) Conversion of light energy to chemical energy (in the form of ATP and NADPH) and splitting of water molecules into hydrogen and oxygen.
(iii) Reduction of carbon dioxide to carbohydrates (carbon assimilation).

Q10: (i) How does Paramecium obtain its food? 
(ii) List the role of each of the following in our digestive system: 
(a) Hydrochloric acid 
(b) Trypsin 
(c) Muscular walls of the stomach 
(d) Salivary amylase (2023)
Ans: (i) In Paramecium, a unicellular protozoan, the hair-like outgrowth cilia are present on the entire surface and help collect the food. They sweep the food inside the body through the oral groove.
(ii) (a) Role of hydrochloric acid: It helps to maintain the acidic pH in the stomach required for activation of the enzyme pepsin that digests proteins in the stomach.
(b) Role of trypsin in our digestion system: Trypsin breaks down protein into smaller peptides in the duodenum of the small intestine. It helps in digesting dietary protein by breaking the chain of amino acids. It also activates some proenzymes present in pancreatic juice.
(c) Role of muscular walls in the stomach in our digestive system: The muscular walls in the stomach contract periodically and thereby help in the churning and mixing of the food with the digestive enzymes and HCI. It helps in chemical digestion.
(d) Role of salivary amylase in our digestive system: Salivary amylase found in saliva breaks down the starch and converts it into the simplest sugar.

Q11: (a) With the help of an activity, explain the action of saliva on the food we eat. 
(b) Why is bile juice important in the process of digestion? (2023)
Ans: (a) The action of saliva on the food we eat is explained with the help of activity as follows: Take two test tubes, A and B. In test tube A, put one teaspoon full of boiled rice, and in test tube B, keep one teaspoon full of boiled rice after chewing it for 3 to 5 minutes. Add 3.4 mL of water in both test tubes and add a few drops of iodine solution to each test tube. In test tube A, the colour of the rice changes because of the absence of any enzyme, while in test tube B, no colour change is observed because when rice is chewed, the amylase enzyme present in saliva breaks down the starch of rice to simple sugars.
(b) Bile juice breaks down fats into fatty acids that can be taken into the body by the digestive tract. In addition, it provides alkaline fluid in the intestine to neutralize the acidic pH of food that comes from the stomach.

Q12: What is the other name of 'tissue fluid'? Write its two functions. (2023)
Ans: Tissue fluid is also called lymph. The functions of tissue fluid are:
(i) It carries digested and absorbed fat from the intestine.
(ii) It drains excess fluid from extracellular space back into the blood.

Q13: What will happen if: 
(a) Xylem tissue in a plant is removed. 
(b) We are injured and start bleeding? (2023)
Ans: (a) If the xylem is removed, transport of water and minerals from the soil would not occur, which leads to the wilting of leaves and, ultimately, the death of the plant.
(b) In case of any injury, when bleeding occurs, platelets circulate around the body and form a mesh-like network or clot at the site of injury.

Q14: (i) What is double circulation?
(ii) Why is the separation of the right side and the left side of the heart useful? How does it help birds and mammals?   (2023)
Ans: (i)
Double circulation is a mechanism in which blood circulates twice through the heart in one complete cycle. Systemic circulation and pulmonary circulation are two pathways through which blood flows in double circulation.
Class 10 Science Chapter 5 Previous Year Questions - Life Processes(ii) The separation of the right and left sides of the heart helps in the separation of oxygenated and deoxygenated blood and allows the highly efficient supply of oxygen to the body. Birds and mammals are warm-blooded animals, and their metabolism is quite complex. They require a constant supply of oxygen. Without proper separation, oxygenated blood can mix with deoxygenated blood, which can cause problems in birds and mammals. Separation of the right side and left side of the heart ensures the circulation of oxygenated blood to different body parts.

Q15: Write one specific function of each of the following organs in relation to excretion in human beings:
(i) Renal Artery
(ii) Urethra
(ii) Glomerulus
(iv) Tubular part of nephron (2023)
Ans: (i) 
Renal artery carries blood from the aorta to the kidneys for filtration.
(ii) The urethra receives urine stored in the bladder and releases it outside.
(iii) Glomerulus filters the blood passing through it and initiates urine formation.
(iv) The tubular part of the nephron allows selective reabsorption of useful substances like glucose, amino acids, salts, and water into the blood capillaries.

Q16: Explain in brief two ways by which leaves of a plant help in excretion. (2023)
Ans: 
Most of the carbon dioxide is released through stomata in leaves. Plants can get rid of excess water by the process of transpiration, i.e., evaporative loss of water. Many plant waste products are stored in leaves, which are excreted when shed off.

2022

Q1: In human alimentary canal, the specific enzyme/ juice secreted in locations (i), (ii) and (iii) are

Class 10 Science Chapter 5 Previous Year Questions - Life Processes(a) (i) Amylase (ii) Pepsin (iii) Bile
(b) (i) Amylase (ii) Bile (iii) Trypsin
(c) (i) Lipase (ii) Amylase (iii) Pepsin
(d) (i) Trypsin (ii) Bile (iii) Amylase                  (2022)
Ans:
(b)
Saliva (i) is secreted in the mouth. Saliva contains an enzyme called salivary amylase for digestion of carbohydrates.
Liver (ii) secretes bile to emulsify fat.
The pancreas (iii) secretes pancreatic juice which contains enzyme trypsin for digestion of proteins.

Question for Previous Year Questions: Life Processes
Try yourself:Q2:  In the following flow chart showing autotrophic nutrition in green plants, A and B respectively are

Class 10 Science Chapter 5 Previous Year Questions - Life Processes                                                                                             (2022)

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Q3: Read the following and answer the questions from (i) to (iv).
Take a healthy potted plant with elongated leaves. Select a leaf and insert about one half of this leaf in a test tube containing KOH and make it air tight. Place the set-up in sun for two hours. Take out the leaf from the test tube and dip it in boiling water for a few minutes. Put this leaf in a beaker with alcohol and boil it in a water bath. Wash the leaf with water and then dip the leaf in iodine solution for a few minutes. The portion of the leaf dipped in KOH solution will not show any change when dipped in iodine solution.

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(i) The function of KOH taken in the test tube is to absorb
(a) released water vapours
(b) released CO2 
(c) released O2 
(d) chlorophyll.                  (2022)
Ans: 
(b)
In the given experiment, KOH (Potassium hydroxide) in the test tube absorbs carbon dioxide; thus, due to the absence of CO2, the leaf fails to produce starch which proves that carbon dioxide is necessary for photosynthesis.

(ii) On the basis of this activity, we may conclude that the factor for photosynthesis is
(a) carbon dioxide
(b) oxygen
(c) chlorophyll
(d) water vapour.                  (2022)
Ans:
(a)
The given experiment demonstrates the requirement of carbon dioxide for photosynthesis. When KOH absorbs the available CO2 from the portion of leaf dipped in it, formation of sugar and starch is inhibited and the portion of leaf dipped in KOH did not show any change when dipped in iodine solution. Thus, it is proved that CO2 is necessary for photosynthesis.

(iii) The event that does not occur in photosynthesis is
(a) absorption of light energy by chlorophyll
(b) reduction of carbon dioxide to carbohydrates
(c) oxidation of carbon to carbon dioxide
(d) conversion of light energy to chemical energy.                  (2022)
Ans:
(c)
Following are the three events that occur during the process of photosynthesis
(i) Absorption of light energy by chlorophyll.
(ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
(iii) Reduction of carbon dioxide to carbohydrates.

(iv) Iodine solution gives blue-black colour with
(a) starch
(b) proteins
(c) glucose
(d) fats.                  (2022)
Ans: 
(a)
The brown coloured iodine will turn blue-black when it reacts with starch.

Q4: The correct statements with reference to single celled organisms are
(i) complex substances are not broken down into simpler substances
(ii) simple diffusion is sufficient to meet the requirement of exchange of gases
(iii) specialised tissues perform different functions in the organism
(iv) entire surface of the organism is in contact with the environment for taking in food.
(a) (i) and (iii)    
(b) (ii) and (iii)
(c) (ii) and (iv)    
(d) (i) and (iv).                  (2022)
Ans: 
(c)
Unicellular organisms are one-celled and perform all the life processes that are essential for maintaining the life of cell or organisms like nutrition, respiration, reproduction, excretion, etc. In single-celled organisms such as Amoeba, complex substances are broken into simpler substances.

Q5: Which one of the following conditions is true for the state of stomata of a green leaf shown in the given diagram?

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(a) Large amount of water flows into the guard cells.
(b) Gaseous exchange is occurring in large amount.
(c) Large amount of water flows out from the guard cells.
(d) Large amount of sugar collects in the guard cells.                  (2022)
Ans:
(c)
The opening and closing of the stomatal pore depends on the turgidity of the guard cells. The given figure shows a closed stomatal pore which occurs when guard cells looses water and become flaccid.

Q6: Assertion (A): Nitrogen is an essential element for plant growth and is taken up by plants in the form of inorganic nitrates or nitrites.
Reason (R) : The soil is the nearest and richest source of raw materials like nitrogen, phosphorus and other minerals for the plants.
(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.                  (2022)
Ans:
(b)

Q7: A student was asked to write a stepwise procedure to demonstrate that carbon dioxide is necessary for photosynthesis. He wrote the following steps. The wrongly worded step is

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(a) both potted plants are kept in dark room for at least three days
(b) bottom of the bell jars is sealed to make them air tight
(c) both potted plants are kept in sunlight after the starch test
(d) a leaf from both the plants is taken to test the presence of starch.                   (2022)
Ans: (c)
Both potted plants should be kept in sunlight for about two hours before the starch test.

Q8: The length of small intestine in a deer is more as compared to the length of small intestine of a tiger. The reason for this is
(a) mode of intake of food
(b) type of food consumed
(c) presence or absence of villi in intestines
(d) presence or absence of digestive enzymes.                  (2022)
Ans:
(b)
Herbivores such as deer eating grass need a longer small intestine to allow the cellulose to be digested. Meat is easier to digest, hence carnivores like tigers have a shorter small intestine.

Q9: The sequence of anaerobic respiration in our muscle cells during heavy exercise is
(a) Class 10 Science Chapter 5 Previous Year Questions - Life Processes
(b) Class 10 Science Chapter 5 Previous Year Questions - Life Processes
(c) Class 10 Science Chapter 5 Previous Year Questions - Life Processes
(d) Class 10 Science Chapter 5 Previous Year Questions - Life Processes                   (2022)
Ans: 
(a)
When there is a lack of oxygen in our muscle cells, pyruvate is converted into lactic acid and energy Therefore, the correct pathway of glucose metabolism in our muscle cells during heavy exercise is:

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q10: The energy released during cellular respiration is used to synthesise
(a) ribosomes 
(b) RBC
(c) ATP 
(d) mitochondria.                  (2022)
Ans: 
(c)
The energy released during cellular respiration is immediately used to synthesise a molecule called ATP which is energy currency of the cell and is used as fuel for cellular activities.

Q11: Which of the following statements are correct in reference to the role of A (shown in the given diagram) during a breathing cycle in human beings?

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(i) It helps to decrease the residual volume of air in lungs.
(ii) If flattens as we inhale.
(iii) It gets raised as we inhale.
(iv) It helps the chest cavity to become larger.
(a) (ii) and (iv) 
(b) (iii) and (iv)
(c) (i) and (ii)
(d) (i), (ii) and (iv)                  (2022)
Ans: 
(a)
During inhalation, we lift our ribs and flatter our diaphragm (A), and the chest cavity becomes larger as a result. Because of this, air is sucked into the lungs and fills the expanded alveoli. When our ribs and diaphragm return to their normal position and the chest cavity becomes smaller, exhalation occurs.
During breathing, the lungs always contain a residual volume of air, so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released. The residual volume remains unchanged in normal conditions.

Q12: Assertion (A) : The rate of breathing in aquatic organisms is much slower than that seen in terrestrial organisms.
Reason (R) : The amount of oxygen dissolved in water is very low as compared to the amount of oxygen in air.
(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.                  (2022)
Ans: 
(d)
The amount of dissolved oxygen in water is fairly low as compared to the amount of oxygen in the air but the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms because the aquatic animals have to breath rapidly to take in sufficient oxygen.

Q13: The function of the lining of mucus in the nasal passage of human beings is to
(a) increase the temperature of inhaled air
(b) move the air in and out
(c) filter the air that we breathe in
(d) absorb oxygen from the air.                  (2022)
Ans:
  (c)
The mucus lining in the nasal passage helps to moisten and warm the inhaled air and also trap dust particles (i.e., helps in filtering the inhaled air).

Q14: In living organisms during respiration which of the following products are not formed if oxygen is not available?
(a) Carbon dioxide + Water
(b) Carbon dioxide + Alcohol
(c) Lactic acid + Alcohol
(d) Carbon dioxide + Lactic Acid                  (2022)
Ans:
(a)
In aerobic respiration, glucose is completely broken down to CO2 and H2O with the production of  a large amount of energy (ATP).

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Thus, CO2 and water are formed as a result of aerobic ; respiration and will not formed in the absence of oxygen (anaerobic respiration).

Q15: Respiratory structures of two different animals-a fish and a human being are shown.
Observe (A) and (B) and select one characteristic that hold true for both of them.

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(a) Both are placed internally in the body of animal.
(b) Both have thin and moist surface for gaseous exchange.
(c) Both are poorly supplied with blood vessels to conserve energy.
(d) In both the blood returns to the heart after being oxygenated.                  (2022)
Ans: 
(b)

Q16: Observe the diagram of an activity given below. What does it help to conclude, when the person exhales into the test-tube?

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(a) Percentage of carbon dioxide is more in inhaled air.
(b) Fermentation occurs in the presence of oxygen.
(c) Percentage of carbon dioxide is more in the exhaled air.
(d) Fermentation occurs in the presence of carbon dioxide.                   (2022)
Ans: (c)
When a person blows air from mouth into the test tube containing lime water, the lime water turn into a white precipitate which appears milky. This occurs because the air we exhale has more carbon dioxide.

Q17: The separation of the right side and the left side of heart is useful to
(a) keep oxygenated blood from mixing with deoxygenated blood
(b) allow a slow supply of oxygen in the body
(c) supply energy to animals with low energy needs
(d) often change their body temperature.                  (2022)
Ans: 
(a)
The right and left sides of the heart are separated by a muscular wall that prevents mixing of oxygenated with deoxygenated blood. Such separation allows a highly efficient supply of oxygen to the body.

Q18: In spring, sugar stored in root or stem tissue of plants is transported to the buds for
(a) the energy needs of the buds to grow
(b) temperature regulation
(c) balancing the storage in different organs
(d) diffusion process.                  (2022)
Ans:
(a)
In spring, new buds are formed. These buds need more energy to grow than other parts of the plant. This energy comes from the sugar stored in root or stem tissue and is transported to the buds by phloem.

Q19: Upward movement of water in tall trees is due to
(a) translocation
(b) excretion
(c) photosynthesis
(d) transpiration.                  (2022)
Ans: 
(d)
In tall trees, the driving force to move water upward is transpiration. During transpiration, as the water evaporates through the stomata in the leaves, it creates a negative pressure in the leaves and xylem tissues.

Q20: Thin walled blood vessels are called
(a) aorta
(b) capillaries
(c) arteries 
(d) vena cava.                  (2022)
Ans: 
(b)
Capillaries are tiny blood vessels which have thin walls and are one-cell thick. Exchange of materials between blood and surrounding cells takes place across these thin walled, capillaries. These also take waste products away from tissues.

Q21: Consider the following statements in connection with the functions of the blood vessels marked A and B in the diagram of a human heart as shown.

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(i) Blood vessel A - It carries carbon dioxide rich blood to the lungs.
(ii) Blood vessel B - It carries oxygen rich blood from the lungs.
(iii) Blood vessel B - Left atrium relaxes as it receives blood from this blood vessel.
(iv) Blood vessel A - Right atrium has thick muscular wall as it has to pump blood to this blood vessel.
The correct statements are
(a) (i) and (ii) only 
(b) (ii) and (iii) only
(c) (ii), (iii) and (iv)
(d) (i), (ii) and (iii).                  (2022)
Ans: 
(d)
Blood vessel A represents pulmonary artery and blood vessel B represents pulmonary vein. Oxygen-rich blood from the lungs comes to the left atrium via pulmonary vein. The left atrium relaxes when it receives blood.

Q22: Identify the two components of phloem tissue that help in transportation of food in plants.
(a) Phloem parenchyma and sieve tubes
(b) Sieve tubes and companion cells
(c) Phloem parenchyma and companion cells
(d) Phloem fibres and sieve tubes                  (2022)
Ans: 
(b)
The two components of phloem tissue that helps in transportation of food in plants are sieve tubes and companion cells.

Q23: In the given diagram, A, B, C and D respectively are

Class 10 Science Chapter 5 Previous Year Questions - Life Processes(a) A - Left kidney; B - Aorta; C - Vena cava; D - Urethra
(b) A - Left kidney; B - Vena cava; C - Aorta; D - Urinary bladder
(c) A - Right kidney; B - Aorta; C - Ureter; D - Urethra
(d) A - Right kidney; B - Vena cava; C - Aorta; D - Urinary bladder                   (2022)
Ans:
(d)
A - Right kidney, B - Vena cava, C - Aorta and D - Urinary bladder.

Question for Previous Year Questions: Life Processes
Try yourself:Q24 : Which one among the following is not removed as a waste product from the body of a plant?         (2022)
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Q25: Read the following and answer the questions from 82(i) to 82(iv).
The figure shown below represents a common type of dialysis called as haemodialysis- It removes waste products from the blood, such as excess salts, and urea which are insufficiently removed by the kidney in patients with kidney failure. During the procedure, the patient's blood is cleaned by filtration through a series of semi-permeable membranes before being returned to the blood of the patient. On the basis of this answer the following questions.

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(i) The haemodialyser has semi-permeable lining c tubes which help
(a) to maintain osmotic pressure of blood
(b) to filter nitrogenous wastes from the dialysin solution
(c) in passing the waste products in the dialysing solution
(d) to pump purified blood back into the body of the patient.                  (2022)
Ans: 
(c)
The semi-permeable lining of the tubes of haemodialyser allow the passage of waste products such as urea, creatinine, etc., from the blood to the dialysing fluid.

(ii) Which one of the following is not a function of artificial kidney?
(a) To remove nitrogenous wastes from the blood
(b) To remove excess fluids from the blood.
(c) To reabsorb essential nutrients from the blood.
(d) To filter and purify the blood.                  (2022)
Ans:
(c)
Artificial kidney is not involved in the reabsorption of essential nutrients from the blood.

(iii) The 'used dialysing' solution is rich in
(a) urea and excess salts
(b) blood cells
(c) lymph    
(d) proteins.                  (2022)
Ans:
(a)
The used dialysing fluid/solution is rich in waste products like urea and excess salts because during the passage of patient’s blood through tubes with a semi-permeable lining, the waste products from the blood pass into the dialysing fluids by diffusion.

(iv) Which part of the nephron in human kidney, serves the function of reabsorption of certain substances
(a) Glomerulus
(b) Bowman's Capsule
(c) Tubules
(d) Collecting Duct                    (2022)
Ans:
(c)
The function of tubules of nephron is to allow the selective reabsorption of useful substances like glucose, amino acids, salts and water into the blood capillaries.

2021


Q1: (i) Plants absorb water from the soil. Explain how it is taken up and transported from the soil.
(ii) "When we are injured and start bleeding, it requires the loss of blood from the system to be minimized." What will happen if the blood loss is not stopped? Is there anything the system could do on its own to prevent the loss? (2021 C)

Ans: (i) Minerals and water needed by the plants are absorbed by roots. The root hairs absorb water from the soil by the process of osmosis and take in minerals by the process of diffusion. Thus, a difference in concentration of ions is created between the roots and the soil, which enables the water to enter into the roots to compensate for the difference in concentration. This water, along with dissolved minerals from the root hairs, passes into xylem vessels through cells of the cortex, endodermis, and pericycle, and then ascent of sap takes place from the xylem of roots into the xylem of stem and finally leaf veins through vessels and tracheids.
(ii) Bleeding leads to a loss of pressure, which reduces the efficiency of the pumping system. When an injury is caused, the blood platelets release certain chemicals which are called the platelet factors (e.g., thromboplastin). These platelet factors help in the clotting of blood. 

2020


Q1: In the human body, the site of absorption of digested food is the small intestine. How is the process of absorption carried out, and why is the absorption of digested food necessary? (2020 C)
Ans: The small intestine is the main region for the absorption of digested food. It consists of the following parts: The inner surface of the small intestine has millions of tiny finger-like projections called villi. These villi increase the surface area for efficient food absorption. Within these villi, many blood vessels are present that absorb the digested food and carry it to the bloodstream. The small intestine in human beings is the site of the complete digestion of food like carbohydrates, proteins, and fats. The absorption of digested food is necessary because an organism takes the complex organic materials by the process of absorption and then utilizes absorbed nutrients for various metabolic processes. With the help of these metabolic processes, the body uses these food nutrients for energy, growth, and cell repair.

Q2: Complete the following flow chart as per the given instructions.   (2020) 
Class 10 Science Chapter 5 Previous Year Questions - Life ProcessesAns: a - Hydrochloric acid (HCI)
b - Pepsin
c - Mucus
d - HCI makes medium acidic for the activation of an enzyme pepsin.
e - Pepsin acts in an acidic medium, which breaks down proteins into peptones.
f - The mucus protects the inner lining of the stomach from the corroding action of HCI.

Q3: (a) State the role played by the following in the process of digestion:
(i) Enzyme trypsin
(ii) Enzyme lipase
(b) List two functions of finger-like projections present in the small intestine. (2020)

Ans: (a) (i) Enzyme trypsin: This enzyme is produced by the pancreas in an inactive form called trypsinogen.
Trypsin converts the remaining proteins into peptones, and the peptones into peptides and amino acids.
(ii) Enzyme lipase: It is secreted by the pancreas and small intestine. Lipase converts fats into fatty acids and glycerol.
(b) Internally, the wall of the small intestine is provided with long finger-like projections called villi. Two functions of villi are:
(i) The villi greatly increase the absorptive surface area of the inner lining of the small intestine.
(ii) Villi are richly supplied with blood vessels that carry absorbed food to all cells of the body, where it is utilized for obtaining energy.

Q4: (a) In the process of respiration, state the function of alveoli.    (2020)
(b) The rate of breathing in aquatic organisms is much faster than that in terrestrial organisms. Give reasons.
(c) Complete the following pathway showing the breakdown of glucose.
Class 10 Science Chapter 5 Previous Year Questions - Life Processes
Ans: (a) Functions of alveoli are:
(i) They increase the surface area for the exchange of gases.
(ii) The thin walls of alveoli facilitate the rapid exchange of oxygen and carbon dioxide between alveolar air and blood.
(b) Aquatic animals like fishes obtain dissolved oxygen from water present through their gills. The amount of dissolved oxygen is quite small compared to the amount of oxygen in the air. Therefore, to obtain the required amount of oxygen from water, aquatic animals have to breathe much faster than terrestrial organisms.
(c)Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q5: Give reasons:
(a) Ventricles have thicker muscular walls than atria.
(b) The transport system in plants is slow.
(c) Circulation of blood in aquatic vertebrates differs from that in terrestrial vertebrates.
(d) During the daytime, water and minerals travel faster through the xylem as compared to the night.
(e) Veins have valves, whereas arteries do not. (2020)

Ans: (a) Since ventricles have to pump blood into various organs with high pressure, they have thicker walls than atria.
(b) The transport system in plants is less elaborate than in animals, as plants are less active, so their cells do not need to be supplied with materials quickly.
(c) The aquatic vertebrates, like fish, have gills to oxygenate blood. The flow of blood in a fish is single circulation because the blood passes through the heart only once in one complete cycle of the body. Terrestrial vertebrates, like birds and humans, have double circulation as the blood travels to the heart twice in one complete cycle of blood, and they have lungs for oxygenation of blood.
(d) During the daytime, water and minerals travel faster through the xylem because the rate of transpiration is higher during the daytime.
(e) The lumen of veins has valves, which allow the blood to flow in only one direction. Thus preventing the backflow of blood.

Q6: (a) "Blood circulation in fishes is different from the blood circulation in human beings”. Justify the statement. 
(b) Describe "blood circulation” in human beings. (NCERT. 2020)
Ans: (a) Fishes have only two chambers in their heart. The blood is pumped to the gills for oxygenation, and from there, it passes directly to the rest of the body. Thus, the blood goes only once through the heart during one cycle of passage through the body. This type of circulation is termed as single circulation. In human beings, during circulation, blood travels twice through the heart in one complete cycle of the body, which is called double circulation. The pathway of blood from the heart to the lungs and back to the heart is called pulmonary circulation, and the pathway of blood from the heart to the rest of the body and back to the heart is called systemic circulation.
(b) In human beings, deoxygenated blood from the body tissues is poured into the right atrium. Contraction of the heart forces it into the right ventricle. From the right ventricle, deoxygenated blood flows to the lungs through the pulmonary artery. Oxygenated blood from the lungs is returned to the left atrium and then into the left ventricle. The left ventricle forces the oxygenated blood to the whole body. Thus, to make one complete round or circulation circuit around all body parts, the blood passes through the heart twice. This is known as the double circulation of blood.

Q7: (a) Describe the structure and function of the basic filtering unit of the kidney.
(b) List two factors on which the reabsorption of water from urine depends. (2020)

Ans: (a) Nephron is the structural and functional unit of the kidney. Its main role is to regulate the concentration of water and soluble substances like sodium and other salts by filtering the blood, reabsorbing the excess water that is needed, and excreting the rest as urine.
(b) Two factors on which the reabsorption of water from urine depends are:

  • The amount of excess water which is present in the body.
  • The amount of dissolved waste that needs to be excreted out of the body.

Q8: (a) Name the organs that form the excretory system in human beings.
(b) Describe in brief how urine is produced in the human body. (NCERT Exemplar, 2020)
Ans:
(a) The Excretory system (urinary system) in human beings consists of a pair of kidneys, a pair of ureters, a urinary bladder and a urethra.
(b) In the kidney, the wastes are converted to urine by three processes:
(i) Ultrafiltration: A large amount of water, along with certain harmful substances like urea, uric acid, K+, ammonium salts, creatinine, etc., and certain useful substances like glucose, amino acids, Na+, etc., pass through glomerular capillaries and glomerular membrane into the cavity of Bowman’s capsule of nephrons under pressure. The filtrate so formed is called nephric filtrate, which is moved towards the ureter.
(ii) Selective reabsorption: A large amount of water and sodium, a whole of glucose and amino acids, and a small amount of urea are passed back from the nephric filtrate into the blood capillaries. It occurs either by back diffusion (i.e., water and urea) or active transport (i.e., Na+, glucose, and amino acids). It generally occurs in the PCT (Proximal convoluted tubule) of nephrons.
(iii) Tubular secretion: Certain harmful chemicals like uric acid, creatinine, K+, etc., are passed from blood capillaries surrounding the nephron into nephric filtrate by active transport. It generally occurs in the DCT (Distal convoluted tubule) of nephrons. Now, the fluid is termed as urine and is excreted out of the excretory organs.

Q9: (a) Why is nutrition necessary for the human body?
(b) What causes the movement of food inside the alimentary canal?
(c) Why is the small intestine in herbivores longer than in carnivores?
(d) What will happen if mucus is not secreted by the gastric glands? (NCERT Exemplar, 2020)

Ans: (a) Nutrition is necessary for the human body because the human body continuously requires energy for life activities like respiration, circulation, excretion, etc. Energy is required even when we are sleeping because a number of biological processes keep on occurring. All these processes require energy, and this energy is obtained from nutrition. It is also needed for the growth and repair of the human body.
(b) The wall of the alimentary tract contains muscles that can contract and expand alternately. The contraction and expansion movement of the wall of the food pipe is called peristaltic movement. The peristaltic movement moves j the partially digested food in all the digestive organs throughout the alimentary canal.
(c) The small intestine in herbivores is longer than in carnivores because herbivores eat plants, rich in cellulose, which takes longer time for complete digestion by the enzymes present in symbiotic bacteria. Therefore, they have longer small intestines. Carnivores feed on flesh, which is easier to digest and does not contain cellulose. Therefore, they have shorter intestines for the digestion of food eaten by them.
(d) Gastric glands secrete HCI, mucus, renin, and pepsin enzymes. The mucus protects the inner lining of the stomach from the action of acidic HCI and enzymes. In the absence of mucus, there would be erosion of the inner lining of the stomach, leading to acidity and ulcers.

Q10: (a) Why is there a difference in the rate of breathing between aquatic organisms and terrestrial organisms? Explain.
(b) Draw a diagram of the human respiratory system and label it - the pharynx, trachea, lungs, diaphragm and alveolar sac on it. (2020)

Ans: (a) Terrestrial organisms inspire atmospheric oxygen, while aquatic organisms thrive on the dissolved oxygen present in water. Air contains about 21% oxygen, while water has less than 1% oxygen in a dissolved state. Oxygen diffuses through water at a much slower rate than in air. A terrestrial organism has the advantage of utilizing greater amounts of oxygen at a faster rate with lesser effort, whereas aquatic organisms have to put more effort into obtaining the same amount of oxygen; therefore, breathing in aquatic organisms is much faster than the terrestrial organisms.
(b) The labelled diagram of the human respiratory system is as follows
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

2019


Q1: Name an enzyme present in pancreatic juice.  [2019 C]
Ans: 
Pancreatic juice contains the digestive enzyme trypsin.

Q2: What causes the movement of food inside the alimentary canal in human beings?  [2019 C]
Ans: 
The movement of food within the alimentary canal is mostly caused by peristalsis. Peristalsis is the rhythmic contraction and relaxation of muscles of the alimentary canal to push the food downward.

Q3: (a) Write the function of the following in the human alimentary canal:
(i) Saliva
(ii) HCI in the stomach
(iii) Bile juice
(iv) Villi
(b) Write one function for each of the following enzymes:
(i) Pepsin
(ii) Lipase           (2019)

Ans: (a) (i) Saliva contains salivary amylase and is released in our mouth. It breaks down starch into sugar (complex carbohydrates into simpler ones).
(ii) Acid (HCI) plays an important role in the process of digestion. These are: 

  • HCl or hydrochloric acid creates an acidic medium inside the stomach, which is essential for the activation and action of the gastric enzyme pepsin. 
  • HCI kills the harmful bacteria present in the food. 
  • Bile brings about the emulsification of fat (i.e., breaks fat molecules into small globules). 
  • Internally, the wall of the small intestine is provided with long finger-like projections called villi. Two functions of villi are: 
  • The villi greatly increase the absorptive surface area of the inner lining of the small intestine. 
  • Villi are richly supplied with blood vessels that carry absorbed food to all cells of the body, where it is utilized for obtaining energy. 

(b) (i) Pepsin is a protein-digesting enzyme present in gastric juice. Pepsin gets activated in an acidic medium and splits proteins into peptones and peptides.
(ii) Lipase is secreted by the pancreas and small intestine. Lipase converts fats into fatty acids and glycerol.

Q4: Write two different ways in which glucose is oxidized to provide energy in the human body. Write the products formed in each case. (Delhi 2019)
Ans: The two different ways by which glucose is oxidized to provide energy in the human body are:
(i) Aerobic respiration (In the presence of oxygen): The end products in aerobic respiration are carbon dioxide, water, and energy.
Class 10 Science Chapter 5 Previous Year Questions - Life Processes(ii) Anaerobic respiration (In the lack of oxygen): The end products are lactic acid and energy.
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q5: Explain the ways in which glucose is broken down in the absence or shortage of oxygen. (2019)
Ans:
In the absence or shortage of oxygen, glucose is oxidized in the following ways:
(i) In cytoplasm, glucose is oxidized to pyruvate and release energy.
(ii) In the muscles of humans, i.e., under anaerobic conditions, pyruvate breaks down to lactic acid and releases energy.
(iii) In yeast, i.e., during the fermentation process, pyruvate converts to ethanol while carbon dioxide releases a certain amount of energy.

Q6: (a) List in tabular form two differentiating features between xylem and phloem. 
(b) Write two advantages of transpiration in plants. (2019 C)
Ans: (a) Differences between transport in the xylem and transport in the phloem are as follows:
Class 10 Science Chapter 5 Previous Year Questions - Life Processes(b) Significance of transpiration in plants: 
(i) The absorbed water is transported from roots to leaves through xylem vessels, which is greatly influenced by transpiration pull.
(ii) The water stream moving upwards carries dissolved minerals with it. Transpiration also helps in distributing these minerals throughout the plant.
(iii) The evaporation of water during transpiration provides a cooling effect to the leaves.

Q7: Write three types of blood vessels. Give one important feature of each. (Delhi 2019)
Ans: The three types of blood vessels in the human body are:
(i) Arteries are the blood vessels that carry blood from the heart to various parts of the body. They are thick-walled, elastic, and muscular, which enables them to dilate but do not rupture when the heart contracts and forces blood into them.
(ii) Veins are thin-walled blood vessels that bring blood from the body back to the heart. They are larger and hold more blood than the arteries. The lumen of veins has valves which prevent the backflow of blood.
(iii) Capillaries are thin-walled and extremely narrow blood vessels that occur at the terminals of arteries and veins. The walls of capillaries are permeable to water and dissolved substances so that the exchange of materials between the blood and body cells can take place.

Q8: (a) Write two water-conducting tissues present in plants. How does water enter continuously into the root xylem? 
(b) Explain why plants have low energy needs as compared to animals.   (AI2019)
Ans: (a) Xylem tracheids and vessels are two water-conducting tissues present in plants that help in the rapid movement of water. In xylem tissue, vessels and tracheids of the roots, stems, and leaves are interconnected to form a continuous system of water-conducting channels reaching all parts of the plant. Minerals and water needed by the plants are absorbed by root hairs from the soil by the process of osmosis and take in minerals by the process of diffusion. Thus, a difference in concentration of ions is created between the roots and the soil, which enables the water to enter into the roots to compensate for the difference in concentration. The water, along with dissolved minerals from root hairs, passes into xylem vessels through cells of the cortex, endodermis, and pericycle and then ascent of sap (i.e., upward movement of water and mineral salts from roots to the aerial parts of the plant against the gravitational force) takes place from xylem of the roots to the xylem of stem and leaves through vessels and tracheids. Evaporation of water molecules from the cells of leaves creates a suction pressure that pulls the water from the xylem cells.
(b) Plants are autotrophic and do not have to move from one place to another in search of their food. Movements in a plant occur at the cellular level, and hence, they require less energy. Animals are heterotrophic and move in search of food and other activities; hence, they require a higher amount of energy than plants.

Q9 List four functions of the human heart. Why is double circulation necessary in the human body? (2019)
Ans: The functions of the human heart are as follows:
(i) The heart maintains the blood pressure.
(ii) The heart pumps vital substances and nutrients to different body parts.
(iii) The heart pumps the oxygen-rich blood to the whole body and CO2-rich blood to the lungs for purification.
(iv) The heart is responsible for removing metabolic waste, such as CO2, from all the tissues of the body. The heart of human beings consists of two sides - right and left. The right side of the heart receives deoxygenated blood and sends it further for purification to the lungs. The left side of the heart receives oxygenated blood from the lungs, which is pumped further and sent to all the parts of the body through blood vessels. This is called double circulation. The energy demands of human beings are too high and hence the separation of oxygenated and deoxygenated blood is necessary to meet high energy demands.

Q10: (a) Define the term excretion. Why should animals excrete waste matter?
(b) Name the main excretory organ of human beings and state the form in which the excretory matter is thrown out of the body. (2019 C)

Ans: (a) Excretion is a biological process by which harmful metabolic wastes like nitrogenous substances are removed from the body. Metabolic activities produce waste products like water, salts, CO2, uric acid, and urea. Accumulation of these excretory wastes beyond a certain limit inside the body is harmful to the body.
(b) A pair of kidneys are the main excretory organs in a human being. It helps excrete nitrogenous waste in the form of urea, toxins, excess salts, water-soluble vitamins, etc. and then eliminates it in the form of urine.

Q11: In the experimental set-up to show that "CO2 is given out during respiration'' name the substance taken in the small test tube kept in the conical flask. State its function and the consequence of its use. (2019)
Ans: In the experiment in which carbon dioxide is given out during respiration, KOH (potassium hydroxide) solution or pellets are taken in a tube and placed within the conical flask. KOH absorbs the carbon dioxide, and it prevents the carbon dioxide from being utilized by the plant for the process of photosynthesis. Function of KOH
KOH: KOH solution kept in the flask absorbs carbon dioxide and creates a partial vacuum in the flask. The air present in the bent tube moves into a conical flask, and this pulls the water level up in the tube. Consequences:

  1. The whole amount of CO2 liberated gets absorbed by KOH to prevent it from being utilized by the plant for the process of photosynthesis.
  2. This CO2 absorption leads to creating a vacuum in a flask that causes an observable rise in the water level of the connected U tube.
  3. Any gas produced can neither escape nor can get outside air in.
  4. Germinating seed produces CO2 via the following reactions: Aerobic respiration: C6H12O+ 6O2 → 6CO2 + 6H2O + 38ATP

2018


Q1: (a) Mention any two components of blood.
(b) Trace the movement of oxygenated blood in the body.
(c) Write the function of valves present in between atria and ventricles.
(d) Write one structural difference between the composition of arteries and veins. (2018)

Ans: (a) Two components of blood are blood plasma and blood corpuscles.
(b) Oxygenated blood from lungs → Pulmonary veins → Left atrium of heart → Left ventricle → Aorta → Arteries → Body parts
(c) When blood is pumped, valves prevent the backflow of blood between ventricles and atria. They open and allow the right amount of blood to flow from one chamber to the other.
(d) Structural difference between veins and arteries is as follows:
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q2: (a) Name the process and explain the type of nutrition found in green plants. List the raw materials required for this process. Give a Chemical equation for the mentioned process.
(b) Write three events that occur during this process.    [CBSE 2018C]

Ans: (a) Photosynthesis is the process where green plants show autotrophic nutrition. The raw materials required for photosynthesis are carbon dioxide water, and energy in the form of sunlight.
The equation is as follows:
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(b) The three events in photosynthesis are:

  • Absorption of light energy by chlorophyll.
  • Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
  • Reduction of carbon dioxide to carbohydrates.

Q3: (a) Write the reaction that occurs when glucose breaks down anaerobically in yeast. 
(b) Write the mechanism by which fishes breathe in water. 
(c) Name the balloon-like structures present in the lungs. List its two functions. 
(d) Name the respiratory pigment and write its role in human beings. [CBSE 2018C]
Ans: (a)  Class 10 Science Chapter 5 Previous Year Questions - Life Processes(b) Fishes breathe with the gills by diffusion.
(c) Alveoli are the balloon-like structures:

  • They provide a surface for the exchange of gases.
  • They contain a residual volume of air so that there is sufficient time for the exchange of gases.

(d) Haemoglobin is the respiratory pigment in humans. It transports a major part of oxygen and some amount of carbon dioxide through the blood.
Q4: (a) Mention any two components of blood.
(b) Trace the movement of oxygenated blood in the body.
(c) Write the function of valves present in between atria and ventricles.
(d) Write one structural difference between the composition of arteries and veins. [CBSE 2018]
Ans: (а) Blood is composed of plasma and three types of cells: red blood cells, white blood cells, and platelets.
(b) 

  • Oxygenated blood from the lungs is brought to the left atrium by pulmonary veins.
  • When the atrium contracts, blood is transferred to the left ventricle.
  • When the ventricle contracts, blood is pushed into the aorta and through arteries to all parts of the body.

(c) The valves prevent the backflow of blood from ventricles into the atria.

(d) Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q5: (а) Define excretion.
(b) Name the basic filtration unit present in the kidney.
(c) Draw the excretory system in human beings and label the following organs of the excretory system that perform the following functions:
(i) form urine.
(ii) is a long tube that collects urine from the kidney.
(iii) store urine until it is passed out. [CBSE 2018]
Ans:
(a) Excretion is the biological process of removal of harmful metabolic wastes from the body.
(b) Nephrons
(c) (i) Kidney, (ii) Ureter, (iii) Urinary bladder.

Class 10 Science Chapter 5 Previous Year Questions - Life ProcessesExcretory System of Human Beings

2017


Q1: Diffusion is insufficient to meet the oxygen requirement of multicellular organisms like humans. State reason. (NCERT, Board Term 1,2017)
Ans:  Due to the higher metabolic rate and the large volume of the body, oxygen cannot diffuse into all cells of the human body quickly as oxygen will have to travel large distances to reach each and every cell. So, diffusion is insufficient to meet the oxygen demand of multicellular organisms.

Q2: Name the vein that brings blood to the left atrium from the lungs. (Board Term 1,2017)
Ans: The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart.

Q3: Explain the significance of photosynthesis. Write the balanced chemical equation involved in the process. (Board Term 1,2017)
Ans: Photosynthesis is important for a number of reasons:
(i) Food: By photosynthesis, green plants synthesize food from simple raw materials like CO2 and H2O. Thus, it sustains life on earth.
(ii) Oxygen: Oxygen released during the process of photosynthesis is needed by animals and humans for respiration. Oxygen also supports the combustion of fuels. The balanced chemical equation involved in the process of photosynthesis is given as:
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q4: Differentiate between autotrophs and heterotrophs and give one example of each. (NCERT Exemplar, Board Term 1,2017)
Ans:
Differences between autotrophs and heterotrophs are as follows:
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q5: Explain how the translocation of materials in phloem tissue in plants is achieved by utilizing energy. (NCERT, Board Term 1,2017)
Ans:
The phloem cells transport the soluble food materials to all parts of the plant. The transport of food from leaves to different parts of the plant is termed translocation. Components of phloem are sieve tubes, companion cells, phloem parenchyma, and phloem fibres.
The food is manufactured in the mesophyll cells (or photosynthetic cells) of a leaf. The manufactured food enters into sieve tubes of the phloem and is transported as a dilute aqueous solution either in an upward or downward direction. Food is transported to all non-green parts of the plant for their growth and metabolic activities.
Besides food molecules, the phloem also transports amino acids, hormones synthesized in the shoot tips and root tips, and other metabolites. In this process, glucose is transferred to phloem tissue using energy from ATP. This increases the osmotic pressure of the tissue, causing the water to move into it (endosmosis). Soluble material is then transferred from phloem tissue to other tissues which have less pressure than in the phloem. Thus, according to the plant’s requirement, the material is translocated from higher osmotic pressure areas to lower osmotic pressure areas.

Q6: Draw a diagram of the human excretory system and label kidney ureters on it.  (Board Term I,2017)
Ans: 
The diagram of the human excretory system is as follows:
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q7: (a) Write the reaction that occurs when glucose breaks down anaerobically in yeast. 
(b) Write the mechanism by which fishes breathe in water. 
(c) Name the balloon-like structures present in the lungs. List its two functions. 
(d) Name the respiratory pigment and write its role in human beings. [CBSE 2017-18 C]
Ans:  (a) Glucose breaks down anaerobically i.e., in the absence of O2; in yeast in the following manner:

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(b) Since fishes are aquatic, they take in O2 dissolved in water. They take water through their mouth, which goes to their gills, where the dissolved oxygen is taken up by the blood and transported. The CO2 is given out through the same passage.

(c) The balloon-like structures in our lungs are the alveoli.
Their functions are:

  • They are very thin-walled and hence help in gaseous exchange.
  • They contain an extensive network of blood vessels that help in the transport of respiratory gases.
  •  They increase the surface area for the absorption of gases.

(d) The respiratory pigment is Haemoglobin.
Its role is:

  • It has an affinity for oxygen and hence helps in the transport of oxygen from alveoli to body tissues.
  • It also has an affinity for CO2 and hence helps in the transport of CO2 from body tissues to alveoli.

Q8: (a) Name the process and explain the type of nutrition found in green plants. List the raw materials required for this process. Give the chemical equation for the mentioned process. 
(b) Write three events that occur during this process. [CBSE 2017-18 C]
Ans: (a) The process of nutrition in green plants is Photosynthesis. The type of nutrition is autotrophic nutrition. Autotrophic nutrition requires sunlight, chlorophyll, water, and carbon dioxide.
Plants prepare their own food in the form of glucose, which gets converted to starch. This is done using COand H2O, which are fixed using energy from sunlight from the chlorophyll molecules present in green plants.
Equation - 

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(b) The three events involved are:

  • Absorption of sunlight by chlorophyll.
  • Conversion of this light energy into chemical energy and splitting of water into H+ and OH- using this energy.
  • Reduction of CO2 to carbohydrate by using H+ produced due to splitting of water.

Q9: (a) Write the name of different components of the transport system in human beings and state their functions in brief. 
(b) How does a blood clot form if a leak develops in the system of blood vessels?   [CBSE 2017-18 C]
Ans: (a) Various components of the transport system and their functions:Class 10 Science Chapter 5 Previous Year Questions - Life Processes

(b) If there is a leak in the blood vessels due to injury, then the blood platelets help plug these leaks. The platelets make the clot by forming a mesh-like structure over the leak in which other blood cells get entangled, ultimately plugging the leak.

2016


Q1: Define translocation in reference to plants. (Board Term 1,2016)
Ans: The transport of food prepared in the leaves, by the process of photosynthesis, to various parts (roots, stems, branches, etc.) of the plant is called translocation.

Q2: Mention the raw materials required for photosynthesis. (NCERT, Board Term I, 2016)
Ans: Raw materials required for photosynthesis are carbon dioxide (CO2), water, light, and chloroplast.

Q3:  Write three points of difference between breathing and respiration.  (Board Term /, 2016)
Ans: Differences between breathing and respiration are as follows:
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q4: Draw a flow chart to show the breakdown of glucose by various pathways. (NCERT Exemplar, Board Term 1,2016)
Ans: Glucose is first broken down in the cell cytoplasm into a three-carbon molecule called pyruvate. Pyruvate is further broken down in the following ways to provide energy.
Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q5: Draw a diagram of the human alimentary canal and label the following:

(i) Part in which starch digestion is initiated.
(ii) Organ in which bile is stored.
(iii) The gland that secretes digestive enzymes as well as hormones.
(iv) Part of the alimentary canal where water is reabsorbed.
(v) Part of the gut where finger-like projections are present to facilitate absorption of digested food.     [CBSE 2016]
Ans: (i) Mouth, (ii) Gall Bladder, (iii) Pancreas, (iv) Large Intestine, (v) Small intestine.

Class 10 Science Chapter 5 Previous Year Questions - Life Processes

Q6: (a) State the form in which the following are stored : 
(i) Unused carbohydrates in plants. 
(ii) Energy derived from food in humans. 
(b) Describe the process of nutrition in the amoeba with the help of a diagram. [CBSE 2016]
Ans: 
(a) 
(i) As starch in fruits/storage roots tubers etc.
(ii) As glycogen.

(b) Amoeba is a unicellular eukaryotic organism that exhibits a holozoic mode of nutrition. Five steps are involved in this mode of nutrition:

  • Ingestion: Amoeba feeds on microscopic organisms. It takes in food using finger-like projections called pseudopodia. It encircles the food and engulfs or ingests it by a process called phagocytosis. The food comes to lie in a vesicle called a phagosome or food vacuole.
  • Digestion: A lysosome fuses with a phagosome, and complex substances are broken down into simpler ones. Such a type of digestion that occurs within a cell is referred to as Intracellular digestion. The digested food then diffuses into the cytoplasm.
  • Absorption and Assimilation: The digested food that has diffused into the cytoplasm is quickly absorbed by the organism and converted into various constituents of protoplasm.
  • Egestion: The undigested food material reaches the rear end of the organism and is thrown out by the process of exocytosis. The membrane of the vesicle fuses with the surface membrane.Class 10 Science Chapter 5 Previous Year Questions - Life Processes

2015


Q1: Give reason: 
(l) Fine hair and mucus are present in the nasal passage. 
(ii) Rings of cartilage are present in the throat. [CBSE 2015]
Ans: (i) Fine hair and mucus are present in the nasal passage so that any dust particles, pathogens, etc., can be trapped in here, and only clean air will enter the lungs. This is one of the defence mechanisms of our body.
(ii) Rings of cartilage are present in the throat so that the trachea does not collapse on respiration.
Q2: Define the term parasite. Name one plant parasite and one animal parasite. Some organisms break down the food material outside the body and then absorb it. Give two examples. [CBSE 2015]
Ans: Parasites are organisms that obtain nutrients from the bodies of other living organisms and harm them as a result.
(i) Plant parasite - cuscuta
(ii) Animal parasite - Tapeworm
Organisms that break down food outside the body and then absorb it are saprophytes.
Example: fungi, bacteria.
Q3: What do the following transport?     [CBSE 2015]
(i) Xylem
(ii) Phloem
(iii) Pulmonary vein
(iv) Vena cava
(v) Pulmonary artery
(vi) Aorta. 

Ans: 
Material transported by:
(i) Xylem: Water and minerals.
(ii) Phloem: Organic molecules like sucrose.
(iii) Pulmonary vein: Oxygenated blood from lungs to heart.
(iv) Venacava: Impure and deoxygenated blood from the body to the heart.
(v) Pulmonary artery: Deoxygenated blood from the heart to the lungs.
(vi) Aorta: Oxygenated blood from the heart to body parts.
Q4: In single-celled organisms, diffusion is sufficient to meet all their requirements for food, gas exchange, or removal of waste, but it is not in the case of multicellular organisms. Explain the reason for this difference. [CBSE 2015]
Ans: In the case of a single-celled organism, the entire surface of the organism is in contact with the environment, and hence, no specific organ for taking in food, exchanging gases, or removing waste may be needed. In multicellular organisms, only the cells of the skin are in direct contact with the environment. Diffusion is a very slow process, and it will take a very long time to reach all the cells of the body parts. Diffusion is insufficient to melt oxygen requirements.
Q5: State the role of the following in the human digestive system: [CBSE 2015]
(a) Digestive enzymes 
(b) Hydrochloric acid 
(c) Villi 
Ans: (a) Digestive enzymes digest the food we eat.
(b) Hydrochloric acid creates an acidic medium to facilitate the action of the enzyme pepsin.
(c) Villi increases the surface area inside the small intestine to facilitate the absorption of food.

2014

Q1: State the location and function of gastric glands. (Board Term 1,2014)
Ans: Gastric glands are present in the wall of the stomach. They secrete gastric juices containing mucus, protein-digesting enzymes pepsin, rennin, and hydrochloric acid (HCI).

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FAQs on Class 10 Science Chapter 5 Previous Year Questions - Life Processes

1. What are the different types of nutrition in living organisms?
Ans. Living organisms exhibit two main types of nutrition: autotrophic nutrition, where organisms can prepare their own food using simple inorganic substances, and heterotrophic nutrition, where organisms rely on consuming other organisms for nourishment.
2. How do plants obtain nutrients for their survival?
Ans. Plants obtain nutrients through the process of photosynthesis, where they use sunlight, water, and carbon dioxide to produce glucose. They also absorb minerals and water from the soil through their roots to support their growth and development.
3. What is the role of enzymes in the process of digestion?
Ans. Enzymes play a crucial role in the process of digestion by breaking down complex molecules into simpler forms that can be absorbed by the body. They help in the breakdown of carbohydrates, proteins, and fats into smaller molecules that can be easily digested and utilized by the body.
4. How do organisms maintain a constant internal environment despite external changes?
Ans. Organisms maintain a constant internal environment through a process known as homeostasis. This involves regulating various physiological processes such as temperature, pH levels, and nutrient levels to ensure the proper functioning of cells and organs despite changes in the external environment.
5. What is the significance of respiration in living organisms?
Ans. Respiration is a vital process in living organisms as it provides the necessary energy for various cellular activities. It involves the breakdown of glucose to release energy in the form of ATP, which is required for growth, movement, and other metabolic processes in organisms.
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