📘 Answer Key
I. Very short answer (3 × 1 = 3)
1Arrange the following taxonomic categories in ascending order: Genus, Family, Order, Class, Species, Phylum, Kingdom
Answer: Species, Genus, Family, Order, Class, Phylum, Kingdom.
2When the inhibitor closely resembles the substrate in its molecular structure and inhibits the activity of the enzyme, it is known as
Answer: Competitive inhibition.
3Volume of air remaining in the lungs even after a forcible expiration is called
Answer: Residual volume.
4Name the joint between the adjacent vertebrae in the vertebral column which permits limited movements.
Answer: Cartilaginous joint (intervertebral disc joint).
5A complex disorder which is associated with loss of glucose through urine, it is successfully treated with insulin therapy. Name the disease.
Answer: Diabetes Mellitus.
II. Short answer (9 × 2 = 18)
7Identify the given biomolecules A and B. [figure: amino acid and fatty acid]
Answer:
A: Amino acid (general structure with amino, carboxyl, and R group).
B: Palmitic acid (saturated fatty acid).
A: Amino acid (general structure with amino, carboxyl, and R group).
B: Palmitic acid (saturated fatty acid).
8Differentiate aestivation and hibernation.
Answer:
Aestivation: Summer dormancy to escape heat and dry conditions.
Hibernation: Winter dormancy to escape cold and conserve energy.
Aestivation: Summer dormancy to escape heat and dry conditions.
Hibernation: Winter dormancy to escape cold and conserve energy.
9E + S ⇌ ES → EP → E + P. (a) Expand ES and EP. (b) Any two factors that affect enzyme action.
(a) ES: Enzyme-Substrate complex; EP: Enzyme-Product complex.
(b) Temperature, pH, substrate concentration, enzyme concentration, inhibitors (any two).
10Observe the figure (starfish & earthworm). (a) Name organisms A and B. (b) Identify the phyla.
Answer:
A: Starfish (Asterias) → Phylum Echinodermata.
B: Earthworm (Pheretima) → Phylum Annelida.
A: Starfish (Asterias) → Phylum Echinodermata.
B: Earthworm (Pheretima) → Phylum Annelida.
11Write suitable terms: (a) Bones hollow with air cavities (b) Property of emitting light (c) Sexes not separate (d) Warm-blooded organisms
Answer:
(a) Pneumatic bones
(b) Bioluminescence
(c) Hermaphrodite / Monoecious
(d) Homeotherms
(a) Pneumatic bones
(b) Bioluminescence
(c) Hermaphrodite / Monoecious
(d) Homeotherms
12ECG diagram: (a) P-wave, QRS complex, T-wave indications. (b) Machine name.
(a) P-wave: atrial depolarisation; QRS: ventricular depolarisation; T-wave: ventricular repolarisation.
(b) Electrocardiograph.
13(a) Three types of muscles in human body. (b) Endoplasmic reticulum of muscle cell known as?
Answer:
(a) Skeletal, smooth (visceral), cardiac.
(b) Sarcoplasmic reticulum.
(a) Skeletal, smooth (visceral), cardiac.
(b) Sarcoplasmic reticulum.
14Double circulation: (a) Identify vessels A and B. (b) Vessel carrying oxygenated blood from lungs to heart.
Answer:
(a) A: Pulmonary artery; B: Aorta.
(b) Pulmonary vein.
(a) A: Pulmonary artery; B: Aorta.
(b) Pulmonary vein.
15Match the following (Renal calculi, Uremia, Renal failure, Glomerulonephritis).
Answer:
Renal calculi — Stone / insoluble crystallised salts
Uremia — Accumulation of urea in blood
Renal failure — Kidney transplantation (or loss of kidney function)
Glomerulonephritis — Inflammation of glomeruli
Renal calculi — Stone / insoluble crystallised salts
Uremia — Accumulation of urea in blood
Renal failure — Kidney transplantation (or loss of kidney function)
Glomerulonephritis — Inflammation of glomeruli
16Identify endocrine glands A and B from diagram.
Answer: A: Thyroid gland; B: Adrenal gland.
III. Long answer (3 × 3 = 9)
17Name the part of brain controlling: (a) Body temperature, hunger (b) Sensory association, memory (c) Respiration, cardiovascular reflexes.
Answer:
(a) Hypothalamus
(b) Cerebrum / Cerebral cortex
(c) Medulla oblongata
(a) Hypothalamus
(b) Cerebrum / Cerebral cortex
(c) Medulla oblongata
18(a) Process to remove urea from blood in kidney failure. (b) Two processes involved in urine formation. (c) Mechanism maintaining concentration gradient in medullary interstitium.
(a) Haemodialysis / dialysis.
(b) Glomerular filtration, tubular reabsorption (or tubular secretion).
(c) Counter‑current mechanism.
19(a) Inspiration/Expiration table: find A and B. (b) Two methods of CO₂ transport.
Answer:
(a) A: Diaphragm & intercostal muscles relax; B: Intra‑pulmonary pressure decreases.
(b) 1. As bicarbonate ions (HCO₃⁻); 2. As carbamino‑haemoglobin; (or dissolved in plasma).
(a) A: Diaphragm & intercostal muscles relax; B: Intra‑pulmonary pressure decreases.
(b) 1. As bicarbonate ions (HCO₃⁻); 2. As carbamino‑haemoglobin; (or dissolved in plasma).
20Organisms A and B (bee / butterfly / arthropod). (a) Phylum? (b) Economically important insect example. (c) Four special characters of this phylum.
Answer:
(a) Phylum Arthropoda.
(b) Honey bee (Apis) / Silkworm (Bombyx) / Lac insect.
(c) 1. Segmented, bilaterally symmetrical body; 2. Chitinous exoskeleton; 3. Jointed appendages; 4. Open circulatory system (or haemocoel; or head–thorax–abdomen; any four).
(a) Phylum Arthropoda.
(b) Honey bee (Apis) / Silkworm (Bombyx) / Lac insect.
(c) 1. Segmented, bilaterally symmetrical body; 2. Chitinous exoskeleton; 3. Jointed appendages; 4. Open circulatory system (or haemocoel; or head–thorax–abdomen; any four).