This MCQ module is based on: Life Processes – NCERT Exercises
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Life Processes – NCERT Exercises
🎓 Class 10
Science
CBSE
Theory
Ch 5 — Life Processes
⏱ ~17 min
🌐 Language: [gtranslate]
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Chapter 5 — Quick Summary
Every living body runs four life-maintenance processes — nutrition, respiration, transportation and excretion — whether the body is active or at rest. In multicellular organisms these processes are carried out by specialised organ systems.
Nutrition
Autotrophs (green plants) use photosynthesis; heterotrophs (animals, fungi) depend on others. In humans, the alimentary canal (mouth→anus) digests food with help from liver and pancreas, and villi absorb it.
Respiration
Breakdown of glucose to release ATP. Aerobic (38 ATP) yields far more energy than anaerobic (2 ATP). Air reaches alveoli; O₂ and CO₂ are exchanged across their thin walls with capillaries.
Transportation
Human heart — 4 chambers; double circulation keeps oxy/deoxy blood separate. Plants use xylem (water, one way) and phloem (food, both ways). Transpiration pull lifts water in tall trees.
Excretion
Kidneys filter blood via nephrons. Urine path: kidney→ureter→bladder→urethra. Dialysis replaces lost kidney function. Plants release wastes via stomata, leaf-fall, bark, gums.
Key Terms
Autotrophic
self-feeding (plants)
self-feeding (plants)
Heterotrophic
depends on others
depends on others
Photosynthesis
6CO₂+6H₂O→glucose+6O₂
6CO₂+6H₂O→glucose+6O₂
Chlorophyll
green pigment
green pigment
Stomata
leaf pores
leaf pores
Guard cells
regulate stomata
regulate stomata
Holozoic
ingestive feeding
ingestive feeding
Saprotrophic
feed on dead matter
feed on dead matter
Parasitic
feed on living host
feed on living host
Enzyme
biological catalyst
biological catalyst
Peristalsis
muscular wave
muscular wave
Bile
emulsifies fats
emulsifies fats
Villi
increase surface area
increase surface area
Aerobic
with O₂ (38 ATP)
with O₂ (38 ATP)
Anaerobic
without O₂ (2 ATP)
without O₂ (2 ATP)
Fermentation
yeast→ethanol+CO₂
yeast→ethanol+CO₂
Lactic acid
muscle cramp cause
muscle cramp cause
Trachea
windpipe
windpipe
Alveoli
gas-exchange sacs
gas-exchange sacs
Diaphragm
breathing muscle
breathing muscle
Haemoglobin
O₂ carrier in RBC
O₂ carrier in RBC
Artery
away from heart
away from heart
Vein
towards heart
towards heart
Capillary
thin-walled exchange
thin-walled exchange
Atrium / Ventricle
upper / lower chambers
upper / lower chambers
Double circulation
blood through heart 2×
blood through heart 2×
Lymph
colourless tissue fluid
colourless tissue fluid
Xylem
water, upward
water, upward
Phloem
food, both directions
food, both directions
Transpiration
water loss from leaves
water loss from leaves
Root pressure
pushes water up
pushes water up
Nephron
kidney functional unit
kidney functional unit
Glomerulus
capillary tuft
capillary tuft
Bowman's capsule
cup around glomerulus
cup around glomerulus
Urea
main N-waste
main N-waste
Dialysis
artificial kidney
artificial kidney
NCERT Exercises with Solutions
1The inner lining of stomach is protected by one of the following from hydrochloric acid. Choose the correct one. (a) pepsin (b) mucus (c) salivary amylase (d) bile
(b) Mucus. A thick mucus layer secreted by the stomach lining shields its cells from being digested by HCl and pepsin.
2The kidneys in human beings are a part of the system for (a) nutrition (b) respiration (c) excretion (d) transportation.
(c) Excretion. Kidneys filter nitrogenous wastes (mainly urea) and excess water from blood.
3The function of saliva in the digestion of food is:
Saliva (from salivary glands) moistens and softens food for easy swallowing. Its enzyme salivary amylase (ptyalin) begins the digestion of starch by converting it into the sugar maltose. Saliva also has antibacterial properties.
4What are the raw materials required for photosynthesis, and where does each come from?
Raw materials: (i) Carbon dioxide — from the air, through stomata. (ii) Water — absorbed from soil by roots, carried up in xylem. (iii) Sunlight — captured by chlorophyll in chloroplasts. (iv) Minerals (N, P, Fe, Mg) — from soil through roots, required to build chlorophyll and proteins.
5How is excretion carried out in a single-celled organism?
Single-celled organisms like Amoeba do not have excretory organs. Their metabolic wastes (especially CO₂ and ammonia) are small molecules that diffuse directly across the cell membrane into the surrounding water. Some freshwater protozoa also have a contractile vacuole that pumps out excess water.
6Why is diffusion insufficient to meet the needs of multicellular organisms like humans?
In multicellular organisms, most cells are deep inside the body, far from the surface. Diffusion is extremely slow over large distances. Further, different organs have specific needs — muscles need lots of O₂, the brain cannot tolerate any break in supply. A dedicated transport system (heart + blood + vessels) is therefore essential to deliver O₂ and nutrients quickly and to remove wastes.
7How do we test the presence of starch in a leaf — that is, how do we confirm that photosynthesis has happened?
Destarch a plant by keeping it in the dark for 48 h, then expose it to sunlight for a few hours. Pluck a leaf. Boil it in water (kills cells), then in alcohol (removes chlorophyll), wash in warm water and add iodine solution. The blue-black colour indicates starch and hence photosynthesis. Regions without chlorophyll remain yellow-brown.
8Explain the structure and working of the human heart with the help of a labelled diagram. Show how oxygenated and deoxygenated blood are kept separate.
The human heart has four chambers — two atria (upper) and two ventricles (lower). A thick muscular septum separates the right side from the left side so that oxygenated and deoxygenated blood never mix. Deoxygenated blood from the body enters the right atrium via the venae cavae; it passes to the right ventricle, which pumps it to the lungs through the pulmonary artery. Oxygen-rich blood returns from the lungs into the left atrium via the pulmonary veins, then moves to the left ventricle, which pumps it through the aorta to the whole body. Valves between the chambers and at the base of the great arteries prevent back-flow. The left ventricle has the thickest wall because it generates the highest pressure. (See labelled diagram Fig 5.12 in Part 3.)
9What is transpiration pull? Explain how it helps in the upward movement of water in plants.
Water evaporates continuously from the surface of mesophyll cells in leaves and escapes through stomata — this is transpiration. As water molecules leave, they are replaced by more water drawn from the xylem. Because water molecules are strongly attracted to each other (cohesion), this creates a continuous suction — the transpiration pull — that drags the entire water column up from the roots through the xylem. In tall trees, this is the main force that lifts water to the topmost leaves (often 70 m or more).
10What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Aerobic: uses O₂; complete breakdown to CO₂ + H₂O; ≈38 ATP; mainly in mitochondria.
Anaerobic: no O₂; glucose partially broken down to ethanol + CO₂ (yeast) or to lactic acid (muscle); only ≈2 ATP; takes place in cytoplasm.
Examples of anaerobic organisms: yeast (fermentation to make bread and alcohol), certain bacteria (like those causing curd to set from milk), parasites like Ascaris, and muscle cells during vigorous exercise (temporarily).
Anaerobic: no O₂; glucose partially broken down to ethanol + CO₂ (yeast) or to lactic acid (muscle); only ≈2 ATP; takes place in cytoplasm.
Examples of anaerobic organisms: yeast (fermentation to make bread and alcohol), certain bacteria (like those causing curd to set from milk), parasites like Ascaris, and muscle cells during vigorous exercise (temporarily).
11How are the alveoli designed to maximise the exchange of gases?
Alveoli are designed for rapid diffusion:
(i) Large surface area: Millions of alveoli give a total surface of about 80 m².
(ii) Very thin wall: Only one cell thick — diffusion distance is minimal.
(iii) Moist inner lining: Gases must dissolve before diffusing; moisture helps.
(iv) Dense capillary network: Each alveolus is wrapped in capillaries, maintaining steep O₂ and CO₂ gradients.
(v) Balloon-like shape: Expands and shrinks with breathing, continuously refreshing air.
(i) Large surface area: Millions of alveoli give a total surface of about 80 m².
(ii) Very thin wall: Only one cell thick — diffusion distance is minimal.
(iii) Moist inner lining: Gases must dissolve before diffusing; moisture helps.
(iv) Dense capillary network: Each alveolus is wrapped in capillaries, maintaining steep O₂ and CO₂ gradients.
(v) Balloon-like shape: Expands and shrinks with breathing, continuously refreshing air.
12What would be the consequences of a deficiency of haemoglobin in our bodies?
Haemoglobin is the red pigment in RBCs that binds and carries O₂. A deficiency (called anaemia) means blood can carry much less O₂. Consequences: constant tiredness, weakness, shortness of breath, pale skin and lips, headaches, dizziness, poor concentration and slow wound healing. In severe cases the heart works harder to compensate, leading to palpitations. Iron-rich foods (spinach, jaggery, dates) and vitamin B12/folic acid help treat nutritional anaemia.
13Describe double circulation in human beings. Why is it necessary?
In double circulation, blood passes through the heart twice in one complete cycle. Pulmonary circulation: right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium (blood loses CO₂, gains O₂). Systemic circulation: left ventricle → aorta → body → venae cavae → right atrium (blood delivers O₂/nutrients, picks up CO₂/wastes).
Why necessary: Warm-blooded mammals like humans need a very high rate of respiration to maintain body temperature. Double circulation keeps oxygenated and deoxygenated blood strictly separate, so tissues always receive fully oxygen-rich blood — maximum efficiency.
Why necessary: Warm-blooded mammals like humans need a very high rate of respiration to maintain body temperature. Double circulation keeps oxygenated and deoxygenated blood strictly separate, so tissues always receive fully oxygen-rich blood — maximum efficiency.
14What are the differences between the transport of materials in xylem and phloem?
| Feature | Xylem | Phloem |
|---|---|---|
| Materials carried | Water, minerals | Food (sugars) |
| Direction | Roots → leaves (upward only) | Leaves → all parts (bidirectional) |
| Cells | Dead, hollow (tracheids, vessels) | Living (sieve tubes, companion cells) |
| Energy required | No — driven by physical forces (transpiration pull, root pressure) | Yes — active loading uses ATP (translocation) |
15Compare the functioning of alveoli in the lungs with that of nephrons in the kidneys.
Similarities: both are the functional units of their respective organs; both have a very thin wall and a rich capillary network; both work by diffusion/filtration between blood and a fluid space; both are present in very large numbers to provide enormous surface area.
Differences:
Alveoli — air-filled sacs in lungs; exchange O₂ and CO₂ between air and blood.
Nephrons — tubular filters in kidneys; remove urea, excess water and salts from blood to form urine.
In short: alveoli handle gases (respiration); nephrons handle soluble wastes (excretion).
Differences:
Alveoli — air-filled sacs in lungs; exchange O₂ and CO₂ between air and blood.
Nephrons — tubular filters in kidneys; remove urea, excess water and salts from blood to form urine.
In short: alveoli handle gases (respiration); nephrons handle soluble wastes (excretion).
16What are the components of the transport system in highly organised plants?
Two conducting tissues: xylem (dead tubular cells — tracheids and vessels — that carry water and dissolved minerals from roots upward to leaves) and phloem (living sieve tubes with companion cells that carry food manufactured in the leaves to every other part of the plant, in either direction). Together they form vascular bundles that run through root, stem and leaves.
Frequently Asked Questions — NCERT Exercises & Intext Questions
How do I solve NCERT Class 10 Science Chapter 5 (Life Processes) exercise questions for the CBSE board exam?
Solve NCERT Chapter 5 — Life Processes — exercise questions by first reading the question carefully, writing down the given data, recalling the relevant concepts like nutrition, respiration, transportation, and applying them step by step. This Part 4 covers every intext and end-of-chapter exercise from the NCERT textbook. Write balanced equations, label diagrams clearly and show each step — CBSE Class 10 board examiners award step marks even if the final answer has a small slip. Practising these solutions strengthens conceptual clarity and builds speed for the board exam.
Are the NCERT intext questions from Life Processes important for the Class 10 board exam?
Yes, NCERT intext questions for Chapter 5 Life Processes are highly important for the CBSE Class 10 Science board exam. Many board questions are directly lifted or only slightly modified from these intext questions, and they test the foundational concepts — nutrition, respiration, transportation — that chapter-end questions build on. Attempt every intext question first, then move on to the exercises. This practice ensures complete NCERT coverage, which is the CBSE exam's primary source.
What types of questions from Life Processes are asked in the CBSE Class 10 Science board exam?
The CBSE Class 10 board paper asks a mix of question types from Life Processes: 1-mark MCQ and assertion-reason, 2-mark short answers, 3-mark explanations, 5-mark long answers with diagrams or derivations, and 4-mark competency-based / case-study questions. These test understanding of nutrition, respiration, transportation, excretion. Practising every NCERT exercise and intext question prepares you to answer all of these formats with confidence.
How many marks does Chapter 5 — Life Processes — carry in the Class 10 Science CBSE paper?
Chapter 5 — Life Processes — is part of the Class 10 Science syllabus and typically contributes 5–9 marks in the CBSE board paper, depending on the annual weightage. Questions are drawn from definitions, reasoning, numerical/descriptive problems and diagrams on topics like nutrition, respiration, transportation. Solving the NCERT exercises in this part is essential because CBSE directly references NCERT for question design.
Where can I find step-by-step NCERT solutions for Chapter 5 Life Processes Class 10 Science?
You can find complete, step-by-step NCERT solutions for Chapter 5 Life Processes Class 10 Science on MyAiSchool. Every intext and end-of-chapter exercise question is solved with full working, labelled diagrams and CBSE-aligned mark distribution. Solutions highlight key points about nutrition, respiration, transportation that examiners look for. This makes revision quick and exam-focused for Class 10 CBSE board students.
What is the best way to revise Life Processes before the Class 10 Science board exam?
The best way to revise Life Processes for the CBSE Class 10 Science board exam is a three-pass approach. First pass: skim the chapter and note down key terms like nutrition, respiration, transportation in a one-page mind map. Second pass: solve every NCERT intext and exercise question without looking at the solution, then self-check. Third pass: attempt previous CBSE board questions and competency-based questions under timed conditions. This structured revision secures full marks for this chapter.
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