Chapter 5 Life Processes Class 10 Important Questions: Life Processes are essential for Class 10 students to build a strong foundation in biology.
This chapter covers the various life processes in living organisms, including nutrition, respiration, transportation, and excretion. Practising CBSE Class 10 Science Life Processes questions and using them for revision helps students understand the concepts clearly, improve accuracy in answering questions, and perform better in exams.
Class 10 Science Life Processes Important Question Answers
Strengthen your understanding of Class 10 Science Chapter 5: Life Processes with these high-yield questions.
Practice concepts like nutrition, respiration, transportation, excretion, and key mechanisms in living organisms to boost your exam score.
Multiple Choice Questions (1 Mark):
1. Desert plants take up which gas at night and prepare an intermediate which is acted upon by the energy absorbed during the day?
(A) Oxygen (B) Carbon dioxide (C) Carbon monoxide (D) Nitrogen
Ans. (B) Carbon dioxide
2. Which of the following organisms does not show a parasitic mode of nutrition?
(A) Cuscuta (B) Ticks (C) Orchids (D) Paramecium
Ans. (D) Paramecium
3. The enzyme trypsin acts on which of the following?
(A) Proteins (B) Fats (C) Lipids (D) Carbohydrates
Ans. (A) Proteins
5. The respiratory pigment haemoglobin has a very high affinity for which gas?
(A) Carbon dioxide (B) Oxygen (C) Carbon monoxide (D) Nitrogen
Ans. (C) Carbon monoxide
6. Bicuspid valve is present between:
(A) left atrium and left ventricle
(B) right atrium and right ventricle
(C) pulmonary artery and right ventricle
(D) aorta and left ventricle
Ans. (A) left atrium and left ventricle
7. When a few drops of iodine solution are added to rice water, the solution turns blue-black in colour. This indicates that rice water contains:
(A) Fats (B) Complex proteins (C) Starch (D) Simple proteins
Ans. (C) Starch
8. Chemicals present in tobacco smoke lead to the breakdown of the elastic tissue in the alveoli. Name this specific condition.
(A) Heart disease (B) Emphysema (C) Bronchitis (D) Lung cancer
Ans. (B) Emphysema
9. Which of the following option shows the transport of oxygen to the cell correctly?
(A) Lungs → pulmonary vein → left atrium → left ventricle → aorta → body cells
(B) Lungs → pulmonary vein → right atrium → right ventricle → aorta → body cells
(C) Lungs → pulmonary artery → left atrium → left ventricle → vena cava → body cells
(D) Lungs → pulmonary artery → right atrium → right ventricle → vena cava → body cells
Ans. (A)
10.
Which of the following events in the mouth cavity will be affected if salivary amylase is lacking in the saliva?
(A) Starch breaking down into sugars
(B) Proteins breaking down into amino acids
(C) Absorption of vitamins
(D) Fats breaking down into fatty acids and glycerol
Ans. (A) Starch breaking down into sugars
11. Which part of nephron allows the selective reabsorption of useful substances like glucose, amino acids, salts and water into the blood capillaries?
(A) Tubules (B) Glomerulus (C) Bowman’s capsule (D) Ureter
Ans. (A) Tubules
Very Short Answer Type Questions
12. In which chamber of heart is oxygenated and deoxygenated blood found?
Sol. Oxygenated blood is found in left atrium and left ventricle and deoxygenated blood is found in right atrium and right ventricle.
13. Name the various factors which affect the rate of photosynthesis.
Sol. The factors which affect the rate of photosynthesis are light, water, temperature, and carbon dioxide.
14. What are the end products of aerobic respiration?
Sol. Carbon dioxide, water and energy.
15. What is peristaltic movement?
Sol. The contraction and expansion of movements of the walls of oesophagus is called peristaltic movement. This movement pushes the food in a forward direction in the alimentary canal.
16. Give any two functions of stomata.
Sol.. (i) Gaseous exchange in respiration.
(ii) Loss of water in the form of vapours in transpiration.
17. What processes are considered essential for maintaining life?
Sol. The processes essential for maintaining life are nutrition, respiration, transportation, excretion and response to stimuli.
18. The breathing cycle is rhythmic, whereas the gaseous exchange is a continuous process. Justify the statement.
Sol. The breathing cycle involves inhalation and exhalation of air due to alternate expansion and contraction of thoracic cavity. Thus, it is a rhythmic process. But exchange of gases is a continuous process as it takes place between the blood and each and every cell by diffusion.
19. Why do herbivores have longer small intestines than carnivores?
Sol. Cellulose is difficult to digest and takes a longer time for complete digestion, so herbivores need a longer small intestine. Meat is easier to digest, hence, carnivores like tigers have shorter small intestines.
Short Answer Type Question
20. Name the glands present in the wall of the stomach that release secretions for the digestion of food. Write the three components of secretion that are released by these glands
Sol. The stomach’s muscular wall contains gastric glands. These glands secrete gastric juices which contain dilute hydrochloric acid, mucus and two protein-digesting enzymes rennin and pepsin.
21. How does the small intestine absorb digested food?
Sol. The innermost layer of the small intestine contains the finger-like projections called villi, which increase the absorption surface area. These villi also comprise blood capillaries to aid in the absorption of simple molecules from food.
22. What advantages does a terrestrial organism have over an aquatic organism in obtaining oxygen for respiration?
Sol. The amount of oxygen in air is more than the amount dissolved in the water. Therefore, terrestrial organisms make less effort to get oxygen than aquatic organisms.
23. How is food transported in plants?
Sol. The food is transported by phloem to the plant parts like roots, fruits, seeds and growing regions. This process is called translocation. In the phloem, sieve tubes are present, which, together with companion cells, translocate food in upward and downward directions. ATP is the energy provided for translocation.
24. Describe the structure of the nephron with functioning.
Sol. A nephron is the structural and functional unit of kidney. It consists of a Glomerulus, a Bowman's capsule, tubules, and Loop of Henle. It functions through ultrafiltration, filters waste and excess fluids from the blood. It also regulates blood pressure, electrolyte balance and blood pH.
25. How do plants get rid of excretory products?
Sol. Plants get rid of oxygen and carbon dioxide through diffusion. When the old branches and leaves become useless, they are shed off. Plants have a mechanism by which the roots release waste products. Raisins or gums are the waste products accumulated near the bark.
26. How is the amount of urine produced regulated?
Sol. The kidney can reabsorb water from the filtrate. This mechanism depends upon the amount of water left in the body and the filtrate. The relative water concentration signals the brain based on whether water is reabsorbed or released. So, this is how the kidneys regulate urine formation.
27. Explain the cause of cramps after excessive physical exercise.
Sol. During excessive physical exercise, the demand of energy is high but the supply of oxygen to produce energy is limited. Therefore, anaerobic respiration provides muscles with some extra energy required under excessive physical activity. Glucose is broken down into lactic acid due to anaerobic respiration. The accumulation of lactic acid causes muscle cramps.
28. In a single-celled organism, diffusion is sufficient to meet all the requirements of food, gas exchange and waste removal, but it is not the case in multicellular organisms. Explain the reason for this difference.
Sol. In single-celled organisms, there is no specific organ related to food intake, gas exchange or waste removal. This is because the entire surface of the organism is in contact with the environment. In multicellular organisms, the skin cells directly interact with the environment. Diffusion is a slow process that takes a very long time to reach all body parts, and it is insufficient to meet oxygen requirements.
29. How do guard cells open and close stomatal pores?
Sol. The opening and closing of the stomatal pore is a function of the guard cells. There is swelling of guard cells when the water flows into them, causing the opening of the stomatal pore. The pore closes if there is a shrinkage of the guard cells. There is a loss of large amounts of water through these stomata. The plant closes these pores when carbon dioxide is not required for photosynthesis. Guard cells become turgid and flaccid based on the water entering and leaving.
30. “All plants give out oxygen during day and carbon dioxide during night.” Give reason.
Sol. Yes, this is because respiration occurs throughout the day and night, but photosynthesis occurs only during the day because one of the most integral components needed for photosynthesis is sunlight. During the day, plants give out oxygen, a byproduct of photosynthesis. Thus, plants give carbon dioxide during the night time, when there is no photosynthesis.
31. Differentiate between autotrophic and heterotrophic nutrition?
Sol: 
32. Differentiate between aerobic and anaerobic Respiration.
Sol:
33. How are the alveoli designed to maximise the exchange of gases?
Sol. The inner surface of the lungs has smaller tubes that terminate in the alveoli, which are balloon-like structures. The extensive network of blood vessels is present in the walls of the alveoli. There are millions of alveoli present in the lungs. The alveolus provides a large surface area for the gaseous exchange. If all the alveoli are unfolded from the two human lungs, it will give an area of about 80 square meters.
34. What are the differences between the transportation of materials between xylem and phloem?
Sol. In xylem, the transportation of water and minerals takes place from the roots to the leaves. The conduction takes place through xylem vessels and tracheids, which are dead tissues. The transportation takes place in phloem from leaves to the other parts of the plant. The process is conducted through sieve tubes and companion cells.
35. What is double circulation in humans? Mention its importance.
Sol. Humans have double circulation as the blood passes twice through the heart in one complete cycle. There are two circulations:
Pulmonary circulation: It begins from the right ventricle, and the blood is expelled into the pulmonary trunk. The blood reaches the vascular system of the lungs, becomes oxygenated and then returns to the heart, i.e. the left atrium through pulmonary veins.
Systemic circulation: It starts from the left ventricle, sending blood to the aorta. The aorta supplies the oxygenated blood to various parts of the body. The aorta divides into arteries, arterioles and then capillaries. The deoxygenated blood collected by the venules join to form veins and vena cava finally and pour back blood into the right auricle of the heart.
Importance: No mixing between oxygenated and deoxygenated blood. Ensures oxygen supply efficiently. Maintenance of body temperature.
36. Mention the three kinds of cells present in blood and write one function of each.
Sol. There are three types of cells present in the blood: red blood cells, white blood cells and platelets.
(i) Red blood cells are biconcave and contain haemoglobin to transport oxygen from the lungs to body cells and take carbon dioxide from the cells to the lungs.
(ii) White blood cells are the body’s defence cells and fight against diseases and infections.
(iii) Platelets are responsible for blood clotting during injuries.
37. What are the three types of blood vessels? Mention one important feature of each.
Sol. The human circulatory system has three types of blood vessels: arteries, veins and capillaries.
(i) Arteries generally carry oxygenated blood from the heart to different parts of the body. They are thick-walled. The pulmonary artery is an exception which carries deoxygenated blood from the heart to the lungs for oxygenation.
(ii) Veins generally carry deoxygenated blood from various organs to the heart. Veins are thin-walled. The pulmonary vein is an exception which carries oxygenated blood to the heart.
(iii) Capillaries are responsible for exchanging material between the blood and the surrounding cells. They are thin-walled and narrow tubes which connect arteries to veins.
38. Write three events that occur in photosynthesis.
Sol.
-
Light energy is absorbed by chlorophyll.
-
Conversion of light energy to chemical energy. There is the splitting of water into hydrogen and oxygen.+
-
Reduction of carbon dioxide to carbohydrates.
39. Explain heterotrophic nutrition. What are the types of heterotrophic nutrition? Explain with examples.
Sol. Heterotrophic nutrition is a type of nutrition where an organism derives its food from another living organism. There are three types:
(i) Saprophytic nutrition – nutrients from dead/decaying matter. Examples: fungi, yeast, bacteria.
(ii) Parasitic nutrition – obtains food from a host. Examples: Cuscuta, roundworms, Plasmodium.
(iii) Holozoic nutrition – complex food is ingested, digested, and absorbed. Examples: Amoeba, frogs, humans.
40. Answer the following questions.
(i) How can haemodialysis save and prolong the life of uremic patients?
Sol. The blood urea level rises abnormally (uremia) in patients suffering from renal failure. In uremic patients, an artificial kidney is used for removing accumulated waste products like urea from the blood by a process called haemodialysis. During the process, the patient’s blood is made to pass through the dialysis machine which filters out the waste material from the blood and the blood is again transfused into the patient’s body. Dialysers work exactly on the principle of kidney. Haemodialysis is performed twice or thrice a week which can save and prolong the life of uremic patients.
(ii) What is emulsification? Name the organ where fat is emulsified in the alimentary canal of human beings.
Sol. During the digestion of fats which is largely done in the small intestine, emulsification is required. Emulsification involves the addition of bile to fat. Bile salts break down fat droplets into smaller ones by reducing the surface tension of fat droplets. This increases further digestion of fat by increasing the lipase action of fat. The process is called emulsification, because it produces a fine emulsion of fats in the aqueous intestinal contents. The small fat droplets provides larger surface area to lipase.
41. Answer the following questions
(i) What happens to the rate of breathing during vigorous exercise and why?
Sol. The rate of breathing increases at the time of physical activities because the demand for oxygen increases. The rate of breathing increases up to 20 to 25 times per minute during vigorous exercise.
(ii) “Fishes show single circulation”. Explain.
Sol. Fishes have only two chambers in their heart, the blood is pumped to the gills to get oxygenated blood 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.
Long Answer Type Questions 5 Marks
42. Answer the following questions.
(i) Why is the breathing rate in aquatic organisms much faster than in terrestrial organisms?
Sol. This is because the amount of oxygen dissolved in water is low as compared to the amount of oxygen present in the air. Aquatic animals take water through their mouth and pass it to the gills, where the blood takes up the dissolved oxygen.
(ii) What is lymph? Write its important functions.
Sol. Lymph is an extracellular, light-yellow coloured, mobile fluid connective tissue which drains into lymphatic capillaries from the intercellular spaces. The composition of lymph or tissue fluid is the same as that of blood plasma but it lacks RBCs and large plasma proteins. Lymph performs many functions such as carrying carbon dioxide and waste materials that diffuse from cells into the tissue fluid, destroying invading microbes with the help of leucocytes (WBCs), and transporting fatty acids and glycerol from the small intestine to the blood.
43. Answer the following questions.
(A) Draw a schematic representation of the transport and exchange of oxygen and carbon dioxide during transportation of blood in human beings and label on it: Lung capillaries, pulmonary artery to lungs, Aorta to body, pulmonary vein from lungs.
Sol. The schematic representation of transport and exchange of oxygen and carbon dioxide is as follows:
(B) What is the advantage of separate channels in mammals and birds for oxygenated and deoxygenated blood?
Sol. In mammals and birds, the two circulatory systems (oxygenated blood and deoxygenated blood) become fully separate, sending low-pressure pumping to the lungs and high-pressure flow of blood to the rest of the body. This prevents any mixing of oxygenated and deoxygenated blood, ensuring maximum supply of oxygen to all body parts. This allows optimum oxidation of glucose to release energy required by these animal groups to maintain their body temperature, making them homeothermic.
44. Answer the following questions.
(A) Draw a diagram of the excretory system in human beings and label on it: Aorta, vena cava, urinary bladder and urethra.
Sol. The schematic representation of the excretory system in human beings is as follows:
(B) List two vital functions of the kidney.
Sol. Two vital functions of kidneys are:
(i) The most important function of kidneys is filtration of blood to excrete the waste products of metabolism. If these waste products, mainly nitrogenous waste such as urea and uric acid, are not removed from the blood, they will start accumulating to unbearable toxic levels.
(ii) Osmoregulation: Kidneys maintain water balance in the body and remove excess water.
Besides filtering out the waste products, the kidneys perform other functions such as secretion of erythropoietin, enzyme renin, maintaining homeostasis, and conversion of inactive form of vitamin D to the active form.
45. Answer the following questions.
(A) Draw a diagram depicting the human alimentary canal, and label on it: Gall bladder, liver and pancreas.
Sol. The labelled diagram of the human alimentary canal is as follows:
(B) State the role of the liver and pancreas.
Sol.
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Liver: Liver is the largest gland of the body that secretes bile juice. Bile juice neutralises acidity of food coming from the stomach, provides an alkaline medium, and helps in digestion of fats in the small intestine by bringing about fat emulsification (conversion of large fat droplets into smaller ones), making it easier for lipase enzyme to act and digest them.
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Pancreas: Pancreas is a soft, lobulated greyish-pink gland which has both endocrine and exocrine parts. Cells of the exocrine part secrete pancreatic juice which contains enzymes like pancreatic amylase, trypsin, and lipase that help in digestion of starch, proteins, and fats, respectively. The cells of the endocrine part secrete hormones glucagon and insulin that take part in glucose metabolism.
(C) Name the organ which performs the following functions in human:
(i) Absorption of digested food
Sol. The absorption of digested food takes place in the small intestine.
(ii) Absorption of water
Sol. Absorption of most of the water from undigested food takes place in the large intestine.
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