CBSE Class 10 Biology Life Processes MCQs Set 15

Multiple Choice Questions (MCQs) for Class 10 Science: Chapter 05 Life Processes

Explore reliable objective questions for Chapter 05 Life Processes tailored for Class 10 learners. Utilizing these Science multiple-choice formats ensures thorough preparation and strengthens problem-solving speed for upcoming school assessments.

Practice Chapter 05 Life Processes MCQs for Class 10 Science

View or download the dedicated Chapter 05 Life Processes MCQ resource below. Practicing these 50 objective questions regularly builds familiarity with standard exam patterns and helps secure higher marks in final Science evaluations.

This set of 35 Life Processes MCQs for CBSE Class 10 Science includes 8 assertion-reason questions, with every answer explained step by step. It revises digestion and absorption, the role of chlorophyll and guard cells, ATP and fermentation, double circulation and dialysis, and is meant for quick self-testing before school and board exams.

Multiple Choice Questions

Question 1: Among the following choose the correct option which includes the organisms that have a holozoic mode of nutrition.
(a) Plasmodium and Amoeba
(b) Parakeet and Amoeba
(c) Paramecium and Plasmodium
(d) Paramecium and Parasite
Show Answer & Explanation

Answer: (b) Parakeet and Amoeba

Explanation:
1. In holozoic nutrition an organism takes in solid food, digests it, absorbs it and egests the waste.
2. Parakeet and Amoeba both feed in this manner, while Plasmodium is a parasite.

Teacher's Note:
1. Holozoic = ingestion, digestion, absorption, assimilation, egestion.
2. Parasites feed on a host.

Question 2: Select the row that has the incorrect information about the type of heterotrophic nutrition of the organism.
(a) Amoeba – holozoic
(b) Mushroom – saprophytic
(c) Lice – parasitic
(d) Lion – parasitic
Show Answer & Explanation

Answer: (d) Lion – parasitic

Explanation:
1. Amoeba and lion take in solid food and digest it inside the body, so they are holozoic.
2. Mushroom is a saprophyte and lice are parasites, so a lion cannot be parasitic.

Teacher's Note:
1. Lion = carnivore with holozoic nutrition.
2. Parasites live on a host.

Question 3: Which is the main function of RBC?
(a) To fight disease in the body
(b) To carry oxygen to different parts of the body
(c) To increase levels of WBC
(d) To coagulate blood from wound
Show Answer & Explanation

Answer: (b) To carry oxygen to different parts of the body

Explanation:
1. RBCs contain haemoglobin, which combines with oxygen.
2. They carry oxygen from the lungs to all body tissues.

Teacher's Note:
1. RBC: oxygen; WBC: defence; platelets: clotting.
2. RBCs are formed in the bone marrow.

Question 4: Which of the following is an incorrect statement?
(a) Organisms grow with time
(b) Organisms must repair and maintain their structure
(c) Movement of molecules does not take place among cells
(d) Energy is essential for life processes
Show Answer & Explanation

Answer: (c) Movement of molecules does not take place among cells

Explanation:
1. Living organisms grow, repair and maintain their structures, and need energy for life processes.
2. Molecules do move between cells, for example by diffusion and transport, so statement (c) is incorrect.

Teacher's Note:
1. Molecular movement is needed for repair and maintenance.
2. Even a resting organism needs energy.

Question 5: The process by which Amoeba obtains food is called
(a) phagocytosis
(b) assimilation
(c) diffusion
(d) absorption
Show Answer & Explanation

Answer: (a) phagocytosis

Explanation:
1. Amoeba engulfs the food particle by forming pseudopodia around it.
2. The food gets enclosed in a food vacuole, and this engulfing of food is called phagocytosis.

Teacher's Note:
1. Phagocytosis means cell eating.
2. Digestion in Amoeba takes place in the food vacuole.

Question 6: Absence of which of these processes would have wasted a lot of glucose?
(a) filtration
(b) reabsorption
(c) secretion
(d) none of these
Show Answer & Explanation

Answer: (b) reabsorption

Explanation:
1. Glucose passes into the filtrate in the glomerulus.
2. It is reabsorbed in the tubule; without reabsorption it would be lost in urine.

Teacher's Note:
1. Selective reabsorption returns glucose, amino acids, salts and water.
2. Filtration is non-selective by size.

Question 7: A student sets up an experiment to study the importance of nutrition in plants. The student takes 2 pots, pot 1 and pot 2, each with the same healthy plant. Both pots were placed in the garden and watered properly. Pot 1 was kept as such, while pot 2 was kept in an air-tight glass box with caustic soda, which absorbs carbon dioxide. After 2 days, the plant kept in the garden is healthy while the plant placed in the container sheds leaves and droops. What is the likely reason for this observation?
(a) Absence of oxygen for survival
(b) Absorption of light by caustic soda restricting growth
(c) Inability to perform photosynthesis
(d) Lack of nutrients in the soil
Show Answer & Explanation

Answer: (c) Inability to perform photosynthesis

Explanation:
1. Caustic soda removes CO2 from the box.
2. Without CO2 the plant cannot carry out photosynthesis, so it cannot make food and droops.

Teacher's Note:
1. CO2 is a raw material of photosynthesis.
2. The control plant in air shows the normal condition.

Question 8: Germs entering the body along with food are killed in the part where the pH is
(a) 10
(b) 7
(c) 3
(d) 11
Show Answer & Explanation

Answer: (c) 3

Explanation:
1. The stomach secretes hydrochloric acid and has a strongly acidic pH of about 1 to 3.
2. This acid kills most germs taken in with food.

Teacher's Note:
1. pH below 7 is acidic.
2. HCl also activates pepsin.

Question 9: The green colour of plants is due to the presence of
(a) chlorophyll
(b) carotene
(c) xanthophyll
(d) starch
Show Answer & Explanation

Answer: (a) chlorophyll

Explanation:
1. Chlorophyll is the green pigment present in the chloroplasts of leaves.
2. Carotene and xanthophyll are yellow-orange pigments, and starch is a stored carbohydrate with no colour.

Teacher's Note:
1. Chlorophyll absorbs red and blue light and reflects green.
2. It traps light energy for photosynthesis.

Question 10: Egg white with pepsin (test tube A) and egg white with pepsin and HCl (test tube B) are kept in two test tubes. In which test tube will the digestion of protein occur?
(a) Test tube A, as pepsin will break down protein into simple molecules
(b) Test tube B, as HCl will break down protein into simple molecules
(c) Test tube A, as pepsin will break down into simple molecules
(d) Test tube B, as HCl will activate pepsin for breakdown of protein into simple molecules
Show Answer & Explanation

Answer: (d) Test tube B, as HCl will activate pepsin for breakdown of protein into simple molecules

Explanation:
1. Pepsin works only in an acidic medium.
2. In test tube B, HCl gives the acidic medium and activates pepsin, so protein is digested.

Teacher's Note:
1. HCl activates pepsin but is not itself the digestive enzyme.
2. Without acid, pepsin remains inactive.

Question 11: Consider the following statements about small intestine and select the one which is NOT correct.
(a) The length of the small intestine in animals differs as it depends on the type of food they eat
(b) The small intestine is the site of complete digestion of food
(c) The small intestine receives secretions from liver and pancreas
(d) The villi of the small intestine absorb water from the unabsorbed food before it gets removed from the body via the anus
Show Answer & Explanation

Answer: (d) The villi of the small intestine absorb water from the unabsorbed food before it gets removed from the body via the anus

Explanation:
1. Statements (a), (b) and (c) are correct facts about the small intestine.
2. Water is absorbed from the unabsorbed food by the large intestine, not by the villi of the small intestine, so (d) is not correct.

Teacher's Note:
1. Villi absorb digested food; the large intestine absorbs water.
2. Read the word NOT carefully in such questions.

Question 12: In which organ does the first digestion of starch occur in humans?
(a) Stomach
(b) Small intestine
(c) Large intestine
(d) Mouth
Show Answer & Explanation

Answer: (d) Mouth

Explanation:
1. Saliva contains salivary amylase.
2. It begins the breakdown of starch to sugar as the food is chewed in the mouth.

Teacher's Note:
1. Starch digestion starts in the mouth.
2. Protein digestion starts in the stomach.

Question 13: The lining of the alimentary canal has certain muscles that contract rhythmically in order to push the food forward. This process is called
(a) translocation
(b) transpiration
(c) peristalsis
(d) autotrophism
Show Answer & Explanation

Answer: (c) peristalsis

Explanation:
1. Rhythmic contraction and relaxation of the muscles of the alimentary canal pushes food forward.
2. This wave-like movement is called peristalsis.

Teacher's Note:
1. Peristalsis takes place from the oesophagus to the intestines.
2. Translocation is the transport of food in plants.

Question 14: Protein, carbohydrate and fat components of food are completely digested in the
(a) stomach
(b) small intestine
(c) large intestine
(d) oesophagus
Show Answer & Explanation

Answer: (b) small intestine

Explanation:
1. The small intestine receives bile, pancreatic juice and intestinal juice.
2. These enzymes complete the digestion of proteins, carbohydrates and fats.

Teacher's Note:
1. Complete digestion occurs only in the small intestine.
2. The stomach only starts protein digestion.

Question 15: An incomplete equation for the digestion of starch using saliva is shown as: Saliva + Starch (in test tube) → ____. What will be the likely outcome of this?
(a) Saliva will break down starch into simple protein molecules
(b) Saliva will convert starch into complex fat molecules
(c) Saliva will break down starch into simple sugar molecules
(d) Saliva will convert starch into complex sugar molecules
Show Answer & Explanation

Answer: (c) Saliva will break down starch into simple sugar molecules

Explanation:
1. Saliva contains salivary amylase.
2. It breaks the complex starch into simple sugar molecules (maltose).

Teacher's Note:
1. Enzymes digest complex molecules into simpler ones.
2. Starch is a carbohydrate, so it cannot become protein or fat.

Question 16:
Assertion (A): In the daytime, CO2 generated during respiration is used up for photosynthesis.
Reason (R): There is no CO2 release during day.
(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.
Show Answer & Explanation

Answer: (c) A is true, but R is false.

Explanation:
1. In the day, the CO2 produced by respiration is used in photosynthesis, so A is true.
2. Respiration goes on all the time, so CO2 is released during the day too; R is false.

Teacher's Note:
1. Respiration occurs day and night; photosynthesis only in light.
2. In the day the plant takes the CO2 of respiration for photosynthesis.

Question 17:
Assertion (A): Pyruvate is a six-carbon molecule.
Reason (R): It is prepared in the cytoplasm as the first step to cellular respiration.
(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.
Show Answer & Explanation

Answer: (d) A is false, but R is true.

Explanation:
1. Pyruvate is a three-carbon molecule formed by the breakdown of six-carbon glucose, so A is false.
2. Glucose is converted to pyruvate in the cytoplasm as the first step of respiration, so R is true.

Teacher's Note:
1. Glucose: 6 carbons; pyruvate: 3 carbons.
2. Glycolysis takes place in the cytoplasm.

Question 18:
Assertion (A): The rate of breathing in aquatic organisms is much faster than in terrestrial organisms.
Reason (R): The amount of oxygen dissolved in water is very high 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.
Show Answer & Explanation

Answer: (c) A is true, but R is false.

Explanation:
1. Water holds very little dissolved oxygen compared with air, so aquatic organisms must breathe faster to get enough oxygen; A is true.
2. R is false because the dissolved oxygen in water is very low, not very high.

Teacher's Note:
1. Air has about 21% oxygen; water has far less dissolved oxygen.
2. Fish breathe at a faster rate than land animals.

Question 19:
Assertion (A): In anaerobic respiration, one of the end products is alcohol.
Reason (R): There is an incomplete breakdown of glucose.
(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.
Show Answer & Explanation

Answer: (a) Both A and R are true, and R is the correct explanation of A.

Explanation:
1. In yeast, anaerobic respiration forms ethanol and CO2, so A is true.
2. Glucose is only partly broken down, so R is true and it explains why energy yield is low and alcohol remains.

Teacher's Note:
1. Incomplete breakdown leaves energy-rich ethanol.
2. Complete breakdown gives CO2 and water.

Question 20: In the experiment to show that carbon dioxide is released during respiration, the small test tube of KOH solution is suspended inside the conical flask to absorb the
(a) air of the flask
(b) moisture of the flask
(c) oxygen of the flask
(d) carbon dioxide of the flask released by the seeds
Show Answer & Explanation

Answer: (d) carbon dioxide of the flask released by the seeds

Explanation:
1. Germinating seeds respire and release CO2 inside the closed flask.
2. KOH absorbs CO2, so the pressure falls and water rises in the delivery tube.

Teacher's Note:
1. KOH is an alkali that absorbs the acidic gas CO2.
2. The rise of water shows that CO2 was released.

Question 21: Read the following statements. (I) X amount of carbon dioxide is produced per molecule of glucose during aerobic respiration. (II) Y amount of carbon dioxide is produced per molecule of glucose during fermentation by yeast. Which of the following is TRUE about X and Y?
(a) X is more than Y
(b) X is less than Y
(c) X is equal to Y
(d) Cannot be determined
Show Answer & Explanation

Answer: (a) X is more than Y

Explanation:
1. In aerobic respiration one glucose molecule is completely broken down into 6 molecules of CO2.
2. In fermentation by yeast, glucose gives 2 molecules of ethanol and 2 molecules of CO2.
3. So X (6) is more than Y (2).

Teacher's Note:
1. Aerobic respiration releases far more CO2 and energy per glucose than fermentation.
2. Write the equations to count carbon atoms.

Question 22:
Assertion (A): Alveoli are designed to maximise the exchange of gases.
Reason (R): The walls of alveoli have an extensive network of blood vessels which help in exchange of gases.
(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.
Show Answer & Explanation

Answer: (a) Both A and R are true, and R is the correct explanation of A.

Explanation:
1. Alveoli are thin-walled balloon-like sacs giving a large surface area, so A is true.
2. The rich network of blood vessels around them carries gases to and from the blood, so R explains A.

Teacher's Note:
1. Large area and thin wall favour diffusion.
2. Capillaries bring blood very close to the air.

Question 23:
Assertion (A): The walls of the ventricle are thicker than the walls of the auricles.
Reason (R): The ventricles have to pump blood to long distances and various organs.
(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.
Show Answer & Explanation

Answer: (a) Both A and R are true, and R is the correct explanation of A.

Explanation:
1. Ventricles pump blood to the lungs and the whole body, so they need strong muscular walls.
2. The atria only push blood into the ventricles, so R explains A.

Teacher's Note:
1. Thicker walls give a stronger pumping force.
2. The left ventricle has the thickest wall.

Question 24:
Assertion (A): The effect of root pressure in transport of water is more important at night.
Reason (R): During day, stomata are open and transpiration takes place which helps in transport of water.
(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.
Show Answer & Explanation

Answer: (a) Both A and R are true, and R is the correct explanation of A.

Explanation:
1. In the day, the strong transpiration pull is the main force raising water.
2. At night the stomata are closed, so root pressure becomes the main force; R explains why root pressure matters more at night.

Teacher's Note:
1. Day: transpiration pull. Night: root pressure.
2. Root pressure is produced by active uptake of ions by roots.

Question 25: Oxygenated blood from lungs enters left atrium through
(a) vena cava
(b) pulmonary artery
(c) pulmonary vein
(d) aorta
Show Answer & Explanation

Answer: (c) pulmonary vein

Explanation:
1. The pulmonary veins bring oxygenated blood from the lungs to the left atrium.
2. The pulmonary artery carries deoxygenated blood to the lungs.

Teacher's Note:
1. Pulmonary vessels are an exception to the rule.
2. Vena cava brings blood from the body to the right atrium.

Question 26: The blood plasma without fibrinogen is called
(a) serum
(b) bone marrow
(c) liquid tissue
(d) none of these
Show Answer & Explanation

Answer: (a) serum

Explanation:
1. Plasma contains the clotting protein fibrinogen.
2. When fibrinogen is removed, the remaining fluid is called serum.

Teacher's Note:
1. Serum = plasma − fibrinogen.
2. Bone marrow makes blood cells.

Question 27: Phloem tissues transport
(a) products of photosynthesis, amino acids and other substances
(b) glucose and amino acids
(c) products of photosynthesis only
(d) water and amino acids
Show Answer & Explanation

Answer: (a) products of photosynthesis, amino acids and other substances

Explanation:
1. Phloem translocates the soluble products of photosynthesis from the leaves to other parts of the plant.
2. It also carries amino acids and other substances.

Teacher's Note:
1. Phloem transport uses energy (ATP) and takes place in both directions.
2. Option (c) says 'only', which is too limited.

Question 28: Where is the dirty blood in our body filtered?
(a) Heart
(b) Lungs
(c) Ureter
(d) Kidneys
Show Answer & Explanation

Answer: (d) Kidneys

Explanation:
1. The kidneys filter the blood to remove nitrogenous wastes such as urea and extra salts.
2. The wastes leave as urine.

Teacher's Note:
1. Renal artery brings waste-laden blood; renal vein takes clean blood away.
2. Lungs remove CO2, not urea.

Question 29: Movement of the synthesized products from the leaves to the roots and other parts of a plant's body takes place through the phloem. This process is known as
(a) translocation
(b) transpiration
(c) transportation
(d) excretion
Show Answer & Explanation

Answer: (a) translocation

Explanation:
1. The transport of food made in the leaves to other parts of the plant through the phloem is called translocation.
2. Transpiration is loss of water vapour.

Teacher's Note:
1. Translocation uses ATP energy.
2. Phloem moves materials in both directions.

Question 30: Single circulation, i.e. blood flows through the heart only once during one cycle of passage through the body, is exhibited by
(a) Labeo, Chameleon, Salamander
(b) Hippocampus, Exocoetus, Anabas
(c) Hyla, Rana, Draco
(d) Whale, Dolphin, Turtle
Show Answer & Explanation

Answer: (b) Hippocampus, Exocoetus, Anabas

Explanation:
1. Fishes have a two-chambered heart, and the blood passes through the heart only once in each round of the body.
2. Hippocampus (sea horse), Exocoetus (flying fish) and Anabas (climbing perch) are all fishes. Other options include reptiles, amphibians or mammals.

Teacher's Note:
1. Single circulation is typical of fishes.
2. Mammals and birds have double circulation.

Question 31: We can assume that a four-chambered heart
(a) will be suitable in cold-blooded animals
(b) will be suitable in warm-blooded animals
(c) will be suitable in both
(d) will be suitable in none
Show Answer & Explanation

Answer: (b) will be suitable in warm-blooded animals

Explanation:
1. Warm-blooded animals need much energy to keep a constant body temperature.
2. A four-chambered heart supplies oxygen efficiently, so it suits them.

Teacher's Note:
1. Cold-blooded animals have low energy needs.
2. Mammals and birds are warm blooded.

Question 32: How is the circulation of blood in fish different from that in humans?
(a) The flow of blood in fish is unidirectional
(b) The heart of fish has more chambers compared to that of a human
(c) The blood goes through heart only once in fishes
(d) The heart in fish is bigger in size
Show Answer & Explanation

Answer: (c) The blood goes through heart only once in fishes

Explanation:
1. Fish have a two-chambered heart, and the blood passes through the heart only once in a complete circuit (single circulation).
2. In humans the blood passes twice through the heart (double circulation).

Teacher's Note:
1. Fish: single circulation; humans: double circulation.
2. Blood flow is one-way in both.

Question 33:
Assertion (A): Plants excrete various waste products during their life processes.
Reason (R): They produce urea just like humans.
(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.
Show Answer & Explanation

Answer: (c) A is true, but R is false.

Explanation:
1. Plants remove oxygen, CO2, water, gums and resins, so A is true.
2. Plants do not produce urea, so R is false.

Teacher's Note:
1. Plants store wastes in vacuoles, old xylem and leaves.
2. Urea is formed in the human liver.

Question 34: Primary nitrogenous waste in humans that is thrown out is
(a) carbon dioxide
(b) ammonia
(c) urea
(d) amino acids
Show Answer & Explanation

Answer: (c) urea

Explanation:
1. In the liver, toxic ammonia is converted to the less toxic urea.
2. Urea is carried by the blood to the kidneys and excreted in urine.

Teacher's Note:
1. Humans are ureotelic.
2. CO2 is not a nitrogenous waste.

Question 35: Urine is produced in
(a) kidney
(b) urethra
(c) ureter
(d) urinary bladder
Show Answer & Explanation

Answer: (a) kidney

Explanation:
1. Urine is formed in the nephrons of the kidney by filtration and selective reabsorption.
2. The ureter, bladder and urethra only carry or store it.

Teacher's Note:
1. Kidney forms urine; bladder stores it.
2. Urethra carries it out.

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