Chapter 5: Life Processes

Important questions — the ones the board asked most (20)

1. Q1Long answer5 marksAsked: 2026

   (A) (a) Draw a labelled diagram showing open and closed stomatal pore. (b) List the main events that occur during the process of photosynthesis. (c) Write a balanced chemical equation showing photo-synthesis in plants. OR (B) (a) Draw a well-labelled diagram of nephron and label atleast 4 of its parts. (b) Write the role of capillary cluster inside Bowman's capsule. (c) What is meant by selective reabsorption ?

   

   Medha Ma’am

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   Model answer · Stomata and photosynthesis events

   1. 1.(a) The diagram shows two stomata side by side. (a) Open stomatal pore: two swollen, bean-shaped guard cells bend apart and leave a wide pore between them. (b) Closed stomatal pore: the same two guard cells have shrunk and lie close together, so the pore is shut.1 mark
   2. 2.Labels on both drawings: guard cells, stomatal pore and chloroplast (the green dots inside the guard cells). Under the drawings: "(a) Open stomatal pore" and "(b) Closed stomatal pore". The guard cells swell when water flows into them, causing the stomatal pore to open, and the pore closes if the guard cells shrink.1 mark
   3. 3.(b) The main events that occur during photosynthesis are: (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. These steps need not take place one after the other immediately.2 marks
   4. 4.(c) Balanced chemical equation for photosynthesis: 6CO2 + 12H2O --(Chlorophyll, Sunlight)--> C6H12O6 (Glucose) + 6O2 + 6H2O1 mark

   Diagram: Draw two stomata side by side: (a) an open stomatal pore with two swollen guard cells and a wide pore between them, and (b) a closed stomatal pore with shrunken guard cells. Label guard cells, stomatal pore and chloroplast on each, and write "(a) Open stomatal pore" and "(b) Closed stomatal pore" under them.

   • Write all three events in order, including "splitting of water molecules into hydrogen and oxygen".
   • Write "Chlorophyll" and "Sunlight" over the arrow in the equation, and write "Glucose" under C6H12O6.
   • Label guard cells and stomatal pore on both the open and the closed stoma.

   Marks split as in the board’s published marking scheme

2. Q2Long answer5 marksAsked: 2025

   (a) (i) "The length of the small intestine in various animals depends on the food they eat." Justify the statement. (ii) Discuss the role of the pancreas and bile juice in the digestion of food in human beings. (iii) How is the small intestine designed to absorb digested food? OR (b) (i) State the role of rings of cartilage present in the throat. (ii) Discuss the role of the ribs and diaphragm when air is taken in during the breathing cycle. (iii) Why do we get muscle cramps during heavy exercise? Explain.

   

   Medha Ma’am

   AskMedha’s AI teacher

   Watch it on the board · 115 s

   Model answer · Small intestine digestion, absorption

   1. 1.(a) (i) The length of the small intestine differs in various animals depending on the food they eat. Herbivores 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.2 marks
   2. 2.(ii) Role of pancreas: The pancreas secretes pancreatic juice into the small intestine. Pancreatic juice contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats.1 mark
   3. 3.Role of bile juice: Bile juice comes from the liver. The food coming from the stomach is acidic, and bile juice makes the medium alkaline in the small intestine so that the pancreatic enzymes can act. Bile also acts on fats: bile salts break large fat globules into smaller globules (emulsify fats), which increases the efficiency of enzyme action.1 mark
   4. 4.(iii) Digested food is taken up by the walls of the small intestine. The inner lining of the small intestine has numerous finger-like projections called villi which increase the surface area for absorption of food. The villi are richly supplied with blood vessels which take the absorbed food to each and every cell of the body.1 mark

   • In (i), name "cellulose" as the reason herbivores need a longer small intestine, and say meat is easier to digest for carnivores.
   • For the pancreas, name both enzymes with their work: "trypsin for digesting proteins" and "lipase for breaking down emulsified fats".
   • For bile, write both roles: it emulsifies fats and makes the medium alkaline "so that the pancreatic enzymes can act".

   Marks split as in the board’s published marking scheme

3. Q3Long answer5 marksAsked: 2024

   35. (a) Design an experiment to demonstrate that carbon dioxide is essential for photosynthesis. Write the observation and conclusion of the experiment. OR (b) (i) In the experimental set-up shown above in diagram (I) atmospheric air is being passed into lime water with a syringe while in diagram (II) air is being exhaled into lime water. The time taken for the lime water to turn milky in both the test tubes is different. Give reason. (ii) Draw the diagram of an open stomatal pore and label (I) Guard cells, and (II) Chloroplast on it. Mention two functions performed by stomata.

   

   Medha Ma’am

   AskMedha’s AI teacher

   Watch it on the board · 125 s

   Model answer · Carbon dioxide essential for photosynthesis

   1. 1.(a) Take two similar healthy potted plants and keep them in the dark for about three days so that their leaves are destarched. OR (b)(i) Exhaled air contains much more carbon dioxide, so the lime water in set-up (II) turns milky sooner.1 mark
   2. 2.(a) Place one plant in an airtight bell jar with a watch glass of potassium hydroxide (KOH), which absorbs carbon dioxide; place the other in a similar bell jar without KOH, and seal both with vaseline. OR (b)(i) Atmospheric air has very little carbon dioxide (about 0.03–0.04%), so the lime water in set-up (I) takes longer to turn milky.1 mark
   3. 3.(a) Keep both plants in sunlight for a few hours, then pluck a leaf from each, boil it in water and then in alcohol, and test it with iodine solution. OR (b)(ii) Diagram of an open stomatal pore between two kidney-shaped guard cells.1 mark
   4. 4.(a) Observation: the leaf of the plant kept with KOH does not turn blue-black; the leaf of the other plant turns blue-black. OR (b)(ii) The guard cells and the chloroplasts inside them are labelled.1 mark
   5. 5.(a) Conclusion: no starch was formed without carbon dioxide, so carbon dioxide is essential for photosynthesis. OR (b)(ii) Two functions of stomata: exchange of gases (CO₂ and O₂) and loss of water by transpiration.1 mark

   Marks split as in the board’s published marking scheme

4. Q4Case-based4 marksAsked: 2026

   Read the following passage and answer the questions given below : The mechanism of photosynthesis is not the same in all plants. In most plants, it depends on gaseous carbon dioxide which diffuses directly into the leaves. However, in some plants, carbon dioxide can be stored as part of a complex carbon compound in the vacuoles of leaf cells. This compound is transferred to the chloroplast and releases carbon dioxide as needed for the process of photosynthesis. It is believed that this special system evolved as an adaptation in those plants whose stomata do not open during the day, so that water can be conserved and they can survive in dry (desert) conditions. Answer any one of (a) or (b) : (a) (i) Which process works at a minimum rate to help these plants survive in dry conditions? (ii) Which part of the leaf is responsible for the exchange of gases during photosynthesis? OR (b) (i) List the events that occur during the process of photosynthesis. (ii) When can these desert plants obtain carbon dioxide from the environment, unlike other plants? (iii) Draw a labelled diagram of stomata with an open stomatal pore.

   How the model answer begins

   1. (a) (i) Transpiration works at a minimum rate in these plants. The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration, and large amounts of water can be lost through the…

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5. Q5Case-based4 marksAsked: 2024

   38. Kidneys are vital organs for survival. Several factors like infections, injury or restricted blood flow to kidneys reduce the activity of kidneys. This leads to accumulation of poisonous wastes in the body, which can even lead to death. In case of kidney failure, an artificial kidney can be used. An artificial kidney is a device to remove waste products from the blood through dialysis. (a) (i) Name the artery that brings oxygenated blood to the kidney. (ii) Name the cluster the thin-walled blood capillaries present in the Bowman's capsule. (b) In human excretory system name the organ which stores urine. Is this organ under hormonal control or nervous control ? (c) (i) List two major steps involved in the formation of urine and state in brief their functions. OR (c) (ii) In which part of the nephron does selective reabsorption take place ? List the factors which the amount of water reabsorbed depends on.

   How the model answer begins

   1. (a) (i) The renal artery brings oxygenated blood to the kidney.

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6. Q6Short answer4 marksAsked: 2026

   Kidneys help to regulate the volume of fluid and various metabolites waste products in the body. Normally, kidney filter about 180 L of fluid daily but the volume actually excreted out is only a litre or two a day. [passage] (a) Write the structure and function of Bowman's capsule. 1 (b) Although kidneys filter a large amount (about 180 L daily) of fluids, still the excretion from the body is only about a litre or two. Why ? 1 (c) What is excretion ? Why is it necessary for any living organism ? 2 OR (c) State two similarities between lungs and kidneys. 2

7. Q7Case-based4 marksAsked: 2025

   The maintenance functions of all living organisms must go on even when they are not doing anything particular. Even when we are just sitting in a class or even asleep, this maintenance job has to go on. These maintenance processes require energy to prevent damage and break-down of cells and tissues, which is obtained by the individual organism from the food prepared by the autotrophs, called producers. (a) Name and define the process by which green plants prepare food. (b) Write chemical equation involved in the above process. (c) (i) State in proper sequence the events that occur in synthesis of food by desert plants. OR (c) (ii) Explain giving reasons what happens to the rate at which the green plants will prepare food (I) during cloudy weather, and (II) when stomata get blocked due to dust.

   How the model answer begins

   1. (a) Green plants prepare food by photosynthesis.

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8. Q8Case-based4 marksAsked: 2024

   Human digestive system is a tube running from mouth to anus. Its main function is to breakdown complex molecules present in the food which cannot be absorbed as such into smaller molecules. These molecules are absorbed across the walls of the tube and the absorbed food reaches each and every cell of the body where it is utilised for obtaining energy. (a) Name the glands present in the buccal cavity and write the components of food on which the secretion of these glands act upon. 1 (b) Two organs have a sphincter muscle at their exit. Name them. 1 (c) What will happen if : (i) mucus is not secreted by the gastric glands. (ii) Villi are absent in the small intestine. 2 OR (c) "Bile juice does not contain any enzyme, yet it has important roles in digestion." Justify the statement. 2

   How the model answer begins

   1. (a) The glands present in the buccal cavity are the salivary glands. They secrete saliva, which contains an enzyme called salivary amylase. It acts on starch, a complex carbohydrate, and breaks it down to give simple…

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9. Q9Short answer3 marksAsked: 2024

   (a) Give reasons for the following: (i) The alveoli in lungs have a vast network of blood vessels. (ii) The respiratory pigment in blood takes up oxygen, not carbon dioxide. (iii) In human body, during anaerobic respiration, a 3-carbon molecule is formed instead of CO2 as the end product. OR (b) (i) Name the movement that occurs in each part of the alimentary canal in human digestive system. How do these movements help in digestion? (ii) Where is bile juice stored in human body? List two roles of bile juice.

   How the model answer begins

   1. (i) The alveoli have a vast network of blood vessels to facilitate efficient exchange of gases. The blood in these vessels releases carbon dioxide into the alveoli and takes up oxygen from the alveolar air.

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10. Q10Short answer3 marksAsked: 2023

    (a) (i) State the role of ATP in cellular respiration. (ii) What ensures sufficient exchange of gases in plants ? (iii) State the conditions on which the direction of diffusion of gases in plant depend upon. OR (b) (i) What is the internal energy reserve in plants and animals ? (ii) How desert plants perform photosynthesis if their stomata remain closed during the day ?

    How the model answer begins

    1. (a)(i) ATP is the energy currency of the cell. The energy released during respiration is used to make ATP, and ATP is broken down to provide energy for all activities of the cell. OR (b)(i) Plants store energy as…

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11. Q11Short answer3 marksAsked: 2026

    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. Explain how this is achieved.

12. Q12Short answer3 marksAsked: 2025

    The digestion of food in human alimentary canal is a complex process. State the enzyme/salt present in the following and mention their function in the process of digestion : (i) Saliva (ii) Bile Juice (iii) Pancreatic Juice

13. Q13Short answer3 marksAsked: 2025

    (i) Study the diagram and name the parts marked as A, B, C and D. (ii) Write the function of A and C.

    How the model answer begins

    1. The diagram shows a neuron (nerve cell). Part A is the dendrite. It is made of the short branches at the end of the neuron where information enters.

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14. Q14Short answer3 marksAsked: 2025

    What is the first step of cellular respiration? In which part of the cell does it occur? Write the equation for the process of breakdown of glucose in a human cell : (i) in the presence of oxygen (ii) due to lack of oxygen

    How the model answer begins

    1. The first step of cellular respiration is glycolysis. In this step, glucose, a six-carbon molecule, is broken down into a three-carbon molecule called pyruvate.

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15. Q15Short answer3 marksAsked: 2025

    Name the blood vessel that brings (i) oxygenated blood (ii) deoxygenated blood, to the human heart. Also name that chamber of the heart which receives deoxygenated blood and state how deoxygenated blood from this chamber is sent to lungs for oxygenation.

    How the model answer begins

    1. (i) The pulmonary vein brings oxygenated blood from the lungs to the heart.

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16. Q16Short answer3 marksAsked: 2025

    Explain why respiration is considered as an exothermic reaction. Give the chemical equation for this reaction.

    How the model answer begins

    1. During respiration, food (glucose) is oxidised in the cells and energy is released, which is used for the body's activities.

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17. Q17Short answer3 marksAsked: 2024

    (i) Why is respiratory pigment needed in multicellular organisms with large body size ? (ii) Give reasons for the following : (a) Rings of cartilage are present in the throat. (b) Lungs always contain a residual volume of air. (c) The diaphragm flattens and ribs are lifted up when we breathe in. (d) Walls of alveoli contain an extensive network of blood vessels.

    How the model answer begins

    1. (i) Respiratory pigment is needed because when the body size of animals is large, the diffusion pressure alone cannot take care of oxygen delivery to all parts of the body.

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18. Q18Short answer3 marksAsked: 2023

    (A) (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 stomach (d) Salivary amylase OR (B) (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 ?

    How the model answer begins

    1. (i) Paramecium (Paramoecium) is a unicellular organism. Its cell has a definite shape, and it takes in food at a specific spot. Food is moved to this spot by the movement of cilia, which cover the entire surface of the…

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19. Q19Short answer3 marksAsked: 2026

    Give differences between the following : (a) Nephron and neuron (b) Sensory nerve and motor nerve (c) Consumers and decomposers

    How the model answer begins

    1. (a) Nephron: the basic filtration unit (structural and functional unit) of the kidney; Neuron: the structural and functional unit of the nervous system. Nephron: filters nitrogenous wastes such as urea from the blood;…

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20. Q20Short answer3 marksAsked: 2026

    Complete the pathways given below, showing the breakdown of glucose. Identify 'A', 'B', 'C', 'D', 'E' and 'F'.

    How the model answer begins

    1. A: Cytoplasm. The first step, the break-down of glucose (a six-carbon molecule) into a three-carbon molecule called pyruvate, takes place in the cytoplasm.

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35 more questions of this chapter, each with its model answer, in the AskMedha app.

Objective questions with the board’s key (10)

1. 1. CBSE 2026

   Which structure in a leaf is mainly responsible for gaseous exchange ?

   • (A) Xylem
   • (B) Stomata ✓
   • (C) Phloem
   • (D) Cuticle

   Answer: (B)

2. 2. CBSE 2026

   Pancreatic juice is secreted by the pancreas which contains some specific enzymes that help in the digestion of food. Choose the correct option from the following :

   • (A) Trypsin digests emulsified fat and lipase digests protein.
   • (B) Trypsin digests protein and lipase digests emulsified fat. ✓
   • (C) Trypsin and lipase both digest fat.
   • (D) Trypsin digests protein and lipase digests carbohydrates.

   Answer: (B)

3. 3. CBSE 2026

   Assertion (A) : In human beings, the respiratory pigment is haemoglobin present in red blood cells. Reason (R) : Haemoglobin has a very high affinity for carbon dioxide.

   • (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.

   Answer: (C)

4. 4. CBSE 2026

   Praveen was given a list of some characteristics related to the process of anaerobic respiration in humans in the form of the following table: | | Location | Condition | End product | | --- | --- | --- | --- | | Characteristic | (i) Muscle cell | (ii) Requirement of presence of oxygen (O2) and carbon dioxide (CO2) | (iii) 3-carbon molecule | Which of the above characteristics is/are related to the above process?

   • (A) (i) and (ii)
   • (B) (i) and (iii) ✓
   • (C) (ii) and (iii)
   • (D) (i) only

   Answer: (B)

5. 5. CBSE 2026

   Observe the figure given below and identify the incorrect step in the setup of this activity :

   • (A) Both plants were kept in a dark room for three days before placing them in separate glass jars.
   • (B) Both plants were covered with separate wooden bell-jars. ✓
   • (C) Vaseline was used by applying glass plates to seal the bottoms of the jars.
   • (D) Both plants were kept in sunlight for a few hours before performing the iodine test for the presence of starch.

   Answer: (B)

6. 6. CBSE 2026

   Assertion (A) : The basic filtration unit in the kidneys, like in the lungs, is a cluster of very thin-walled blood capillaries. Reason (R) : Each capillary cluster in the kidney is associated with the cup-shaped end of a coiled tube called Bowman's capsule.

   • (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   • (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A). ✓
   • (C) Assertion (A) is true, but Reason (R) is false.
   • (D) Assertion (A) is false, but Reason (R) is true.

   Answer: (B)

7. 7. CBSE 2026

   Observe the given figure and select the option that correctly represents the mode of nutrition of this fungus :

   • (A) By eating the bread on which they are growing.
   • (B) By using the nutrients present in the bread to make their own food.
   • (C) By breaking down the nutrients of the bread outside the body and then absorbing them. ✓
   • (D) By allowing other organisms to grow on the bread and then consuming them.

   Answer: (C)

8. 8. CBSE 2026

   In human beings the oxygen rich blood is pumped out to the body by :

   • (A) contraction of right atrium
   • (B) relaxation of left ventricle
   • (C) contraction of right ventricle
   • (D) contraction of left ventricle ✓

   Answer: (D)

9. 9. CBSE 2026

   The carbohydrates, which are not used immediately in plants, are stored in the form of 'a', which serves as an internal energy reserve. What does 'a' stand for ?

   • (A) Starch ✓
   • (B) Sugar
   • (C) Fat
   • (D) Protein

   Answer: (A)

10. 10. CBSE 2026

    The following events occur during the process of photosynthesis. Choose the option that indicates the correct events. (i) Oxidation of carbon dioxide to carbohydrates (ii) Conversion of light energy into chemical energy (iii) Absorption of light energy by chlorophyll (iv) Conversion of hydrogen and oxygen into water Options :

    • (A) (i) and (ii)
    • (B) (ii) and (iii) ✓
    • (C) (iii) and (iv)
    • (D) (i) and (iv)

    Answer: (B)

Questions parents and students ask

How many marks does "Life Processes" carry in CBSE Class 10 Science?

In the CBSE papers of 2023–2026, this chapter carried about 8 marks and about 5 questions a year; by marks it ranks 1 in Science.

Which are the most important (VVI) questions of "Life Processes"?

The 20 questions above are from the board’s real papers, each with the years it was asked; the most-asked come first with their full model answers. All 55 written questions of this chapter, with answers, are in the AskMedha app.

Do the answers follow the board’s marking scheme?

Yes. CBSE publishes its marking schemes; every model answer here is written point by point to the marks the board’s own scheme gives, and checked by a second, independent model.