BioNotesBiology Practice Papers
Full-length ICSE Class X and ISC Class XII Biology practice question papers with comprehensive step-marking schemes aligned to the 2027 CISCE pattern.
ICSE Class X Biology Practice Paper 1 - Question Paper
Practice question paper (80 marks, 2 hours) for ICSE Class X Biology, Science Paper 3, 2027 pattern.
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Online
Marking scheme and model answers for ICSE Class X Biology Practice Paper 1, 2027 pattern.
Marks are awarded point-wise, in the manner of CISCE step-marking. Alternative correct answers should be accepted.
| Q | Answer | Q | Answer | Q | Answer |
|---|---|---|---|---|---|
| (i) | (b) imbibition | (vi) | (b) P, Q and S | (xi) | (a) (A) is true and (R) is false |
| (ii) | (c) Both true, R correct explanation | (vii) | (c) medulla oblongata | (xii) | (b) sulphur dioxide and oxides of nitrogen |
| (iii) | (b) Growth hormone | (viii) | (b) Malpighian capsule | (xiii) | (b) 50 |
| (iv) | (b) 4 | (ix) | (b) Presbyopia – convex (bifocal) lens | (xiv) | (d) Neanderthal man |
| (v) | (b) all carriers with normal vision | (x) | (d) O | (xv) | (c) DDT |
Working notes:
(i) [5 × 1]
(a) Rhodopsin (visual purple)
(b) Guttation
(c) Centromere
(d) Ureter
(e) Active transport
(ii) [5 × 1]
(a) platelets
(b) prothrombin
(c) calcium
(d) fibrinogen
(e) Heparin
(iii) [5 × 1] (½ mark for odd one out + ½ mark for category)
| Odd one out | Category of remaining three | |
|---|---|---|
| (a) | Spinal cord | Parts of the brain |
| (b) | Insulin | Plant growth regulators (plant hormones) |
| (c) | Transpiration | Tropic movements in plants |
| (d) | Ureter | Parts of a nephron |
| (e) | Nitrogen | Greenhouse gases |
(iv) [5 × 1]
(a) Reflex action (natural / involuntary reflex)
(b) Spinal cord
(c) Sensory (afferent) neuron
(d) Any one: A reflex action is involuntary and rapid, controlled by the spinal cord, whereas a voluntary action is under conscious control of the cerebrum and is slower.
(e) Any one: Salivation at the sight/smell of food; a cyclist applying brakes on seeing an obstacle; typing/driving habits.
(v) [5 × 1]
Oxytocin – (a); ADH – (b); Glucagon – (c); Adrenaline – (d); Thyroxine – (e).
(i) [1] Osmosis (endosmosis).
(ii) [2] Osmosis is the movement of water (solvent) molecules from a region of higher water concentration (lower solute concentration) to a region of lower water concentration (higher solute concentration) through a selectively permeable membrane.
(iii) [2] The level will not rise [1]. Boiling kills the cells and destroys the selectively permeable nature of the cell membrane, so osmosis cannot occur [1].
(iv) [2] (any two, 1 mark each)
| Osmosis | Diffusion |
|---|---|
| Movement of solvent (water) only | Movement of any type of molecules (solid, liquid, gas) |
| Requires a selectively permeable membrane | Does not require a membrane |
| Occurs through a membrane from dilute to concentrated solution | Occurs from higher to lower concentration of the diffusing substance |
(v) [3] Diagram of Ganong's potometer — 1 mark for correct diagram, 2 marks for any four correct labels.
www.bionotes.inLabels: Plant shoot, Water reservoir, Capillary tube, Air bubble, Beaker of water, Stopcock.
(i) [1] Haemodialysis (dialysis).
(ii) [2] (a) Renal artery [1]; (b) Renal vein [1].
(iii) [2] (any two)
| Glomerular filtrate | Urine |
|---|---|
| Contains glucose and amino acids | Glucose and amino acids absent (reabsorbed) |
| Contains a large volume of water | Water content is much less (reabsorbed) |
| Urea in low concentration | Urea in high concentration |
(iv) [2] (a) Bowman's (Malpighian) capsule / glomerulus [1]; (b) Proximal convoluted tubule [1].
(v) [3] 1 mark for correct diagram, 2 marks for any six correct labels.
www.bionotes.inLabels: Afferent arteriole, Efferent arteriole, Glomerulus, Bowman's capsule, Proximal convoluted tubule (PCT), Loop of Henle, Distal convoluted tubule (DCT), Collecting duct.
(i) [1] Global warming (enhanced greenhouse effect).
(ii) [2] Carbon dioxide [1]; Methane [1] (also acceptable: nitrous oxide, CFCs).
(iii) [2] (any two) Melting of polar ice caps/glaciers; rise in sea level and flooding of coastal areas; change in rainfall pattern/climate; spread of diseases; damage to crops.
(iv) [2] Ozone layer [1]; increased UV radiation reaching the Earth causes skin cancer / cataract / weakened immunity [1] (any one).
(v) [3] (any three, 1 mark each) Use of unleaded petrol/CNG in vehicles; switching off engines at traffic signals; social forestry/planting trees; following Euro Bharat vehicular standards; use of scrubbers and electrostatic precipitators in industries; using public transport.
(i) [1] Gregor Mendel.
(ii) [2] Parents: Tt (heterozygous tall) × tt (dwarf) [1].
Gametes: T and t from the first parent; only t from the second [1].
(iii) [2]
| t | t | |
|---|---|---|
| T | Tt | Tt |
| t | tt | tt |
Genotypic ratio: 1 Tt : 1 tt; Phenotypic ratio: 1 tall : 1 dwarf (Punnett square 1 mark, ratio 1 mark).
(iv) [2] Male: X and Y; Female: X and X [1]. The father determines the sex of the child, as he produces two types of sperm (X-bearing and Y-bearing) [1].
(v) [3] 1 mark for correct diagram, 2 marks for any four correct labels.
www.bionotes.inLabels: Centromere, Sister chromatids, Telomere, Short (p) arm, Long (q) arm, Kinetochore.
(i) [1] To show that light is necessary for photosynthesis.
(ii) [2] To remove the starch already present in the leaves [1]; this step is called destarching [1].
(iii) [2] Iodine solution [½]; (a) covered part – brown/yellow-brown (no starch) [1]; (b) uncovered part – blue-black (starch present) [½].
(iv) [2] Site: Grana (thylakoid membranes) of the chloroplast [1]. Products: ATP and NADPH (also O₂ from photolysis of water) — any two [1].
(v) [3] 1 mark for correct diagram, 2 marks for any four correct labels.
www.bionotes.inLabels: Outer membrane, Inner membrane, Stroma, Granum (stack of thylakoids), Thylakoid, Stroma lamellae.
(i) [1] Retina.
(ii) [2] Accommodation is the ability of the eye to adjust the focal length of the lens so that clear images of objects at different distances are formed on the retina [1]. It is brought about by the ciliary muscles [1].
(iii) [2] Cause: elongation of the eyeball (or an excessively convex lens), so the image forms in front of the retina [1]. Correction: concave lens [1].
(iv) [2] The blind spot is the point on the retina where the optic nerve leaves the eye [1]. It is called so because it has no rods or cones and hence no vision is possible there [1].
(v) [3] 1 mark for correct diagram, 2 marks for any four correct labels.
www.bionotes.inLabels: Cornea, Aqueous humour, Iris, Pupil, Lens, Vitreous humour, Retina, Choroid, Sclera, Macula (yellow spot), Blind spot, Optic nerve.
Diagrams in the marking scheme are from the BioNotes diagram bank. Question–answer design by the BioNotes teaching team; syllabus alignment: CISCE ICSE 2027 Biology (Science Paper 3).
Biology Practice Papers
Full-length ICSE Class X and ISC Class XII Biology practice question papers with comprehensive step-marking schemes aligned to the 2027 CISCE pattern.
ICSE Class X Biology Practice Paper 1 - Question Paper
Practice question paper (80 marks, 2 hours) for ICSE Class X Biology, Science Paper 3, 2027 pattern.