Life Processes: Class 10 Important Questions with Answers

Case-based questions (4 marks each)

(i) Which substance built up in her muscles? (1) (ii) Write the pathway of glucose breakdown in her muscle cells. (1) (iii) Why does she breathe fast after the race, and why is aerobic respiration better for her? (2)

(i) Name the upper and lower chambers. (1) (ii) Why are the lower balloons thick-walled? (1) (iii) Trace the path of blood from the body back to the body, and name the type of circulation. (2)

(i) Name the process of water loss and the pores involved. (1) (ii) Name the tissue that carries water up and the force that works mainly at night. (1) (iii) Give two uses of this water loss for the plant and explain how the pores open and close. (2)

(i) Name the unit of the kidney that filters blood. (1) (ii) What happens to most of the 180 L? (1) (iii) How does the machine remove wastes, and how is it different from a real kidney? (2)

20 MCQs (1 mark each)

1. Cuscuta (amar-bel) shows
   (a) autotrophic (b) saprophytic (c) parasitic (d) holozoic nutrition
2. Extra glucose is stored in plants as
   (a) glycogen (b) starch (c) cellulose (d) sucrose
3. Iodine turns starch
   (a) red (b) blue-black (c) green (d) yellow
4. KOH is used in Activity 5.2 to
   (a) give O₂ (b) absorb CO₂ (c) absorb water (d) give light
5. Stomata open when guard cells
   (a) shrink (b) swell with water (c) die (d) lose chlorophyll
6. Food is taken in at a specific spot in
   (a) Amoeba (b) Paramoecium (c) yeast (d) mushroom
7. Pepsin acts on
   (a) starch (b) fats (c) proteins (d) nucleic acids
8. Bile is made in the
   (a) gall bladder (b) pancreas (c) liver (d) stomach
9. Emulsification of fats is done by
   (a) lipase (b) bile salts (c) HCl (d) trypsin
10. Villi mainly help in
    (a) digestion (b) absorption (c) peristalsis (d) secretion of HCl
11. Anaerobic respiration in yeast gives
    (a) lactic acid (b) CO₂ + water (c) ethanol + CO₂ (d) only water
12. Pyruvate is broken down using O₂ in
    (a) cytoplasm (b) mitochondria (c) chloroplast (d) nucleus
13. CO₂ is mostly transported in blood
    (a) by haemoglobin (b) dissolved in plasma (c) by platelets (d) by WBCs
14. Oxygen-rich blood from lungs enters the
    (a) right atrium (b) left atrium (c) right ventricle (d) left ventricle
15. A fish heart has
    (a) 2 (b) 3 (c) 4 (d) 1 chambers
16. Valves are present in
    (a) arteries (b) veins (c) capillaries (d) none
17. Normal blood pressure is about
    (a) 80/120 (b) 120/80 (c) 140/100 (d) 100/60 mm Hg
18. Transport of food in plants takes place through
    (a) xylem (b) phloem (c) stomata (d) root hairs
19. The filtration unit of the kidney is the
    (a) neuron (b) nephron (c) ureter (d) alveolus
20. Urine is stored in the
    (a) kidney (b) ureter (c) urinary bladder (d) urethra

Answer key

Why: 8 → bile is made in the liver and only stored in the gall bladder · 17 → systolic/diastolic = 120/80.

Assertion–Reason (10)

(a) Both A and R true, R explains A · (b) Both true, R does not explain A · (c) A true, R false · (d) A false, R true

1. A: Diffusion is enough for O₂ supply in humans. R: Humans are multicellular. → (d)
2. A: Only green parts of a variegated leaf turn blue-black with iodine. R: Chlorophyll is necessary for photosynthesis. → (a)
3. A: Herbivores have a longer small intestine than carnivores. R: Cellulose takes longer to digest. → (a)
4. A: Mucus is secreted in the stomach. R: Mucus digests proteins. → (c) it protects the lining
5. A: Rings of cartilage are present in the trachea. R: They prevent the air passage from collapsing. → (a)
6. A: Aerobic respiration releases more energy than anaerobic. R: Aerobic respiration takes place in the cytoplasm only. → (c)
7. A: Arteries have thick elastic walls. R: Blood in arteries flows under high pressure. → (a)
8. A: In plants, transpiration pull is the main force for water movement during the day. R: Stomata are open during the day. → (a)
9. A: Translocation in phloem needs energy. R: Xylem cells are dead. → (b)
10. A: Dialysis involves reabsorption of useful substances. R: The dialysing fluid has no nitrogenous wastes. → (d)

Give reasons (2 marks each)

1. The rate of breathing in aquatic animals is faster than in terrestrial animals.

The amount of oxygen dissolved in water is much lower than in air, so aquatic animals must breathe faster to get enough O₂. 2

2. Ventricles have thicker muscular walls than atria.

Ventricles pump blood to the lungs and the whole body at high pressure; atria only push blood into the ventricles. 2

3. Plants have low energy needs and slow transport.

They do not move and many of their tissues are made of dead cells. 2

4. Lungs always contain a residual volume of air.

It gives enough time for O₂ to be absorbed and CO₂ to be released during each breathing cycle. 2

5. Food coming from the stomach must be made alkaline in the small intestine.

Pancreatic enzymes act only in an alkaline medium; bile from the liver neutralises the acid. 2