ICSE · Class 10 · Code 523

ICSE Class 10 Science — Biology — Important Questions

Question types and patterns from official CISCE board papers 2023, 2024, and 2025. Every topic below has appeared in at least one recent board examination.

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Section A — Compulsory (Questions 1–2, 40 marks)

Q1: 15 MCQs (1 mark each). Q2: Five parts of 5 marks each — naming, labelling diagrams, sequencing, matching.

Reproductive System

Q1 MCQ + Q2 every year

·Hormone inducing uterine contractions: Oxytocin
·Assertion: seminal vesicles pour alkaline secretion (true); reason about ureter — false (correct organ is urethra)
·Name fully developed part of ovary with mature ovum: Graafian follicle

Eye and Vision

Q1 MCQ + Q2 every year

·Structure at junction of choroid and iris: ciliary body
·Owls have large eyes with rods and rhodopsin for night vision
·Cataract: affects lens, causes blurred vision; identify from picture — exophthalmic goitre (over-secretion of thyroxine)

Genetics — Mendel's Laws

Q1 MCQ + Q8 every year

·Cutting tails of mice (acquired characteristic) → offspring have tails: supports Darwin against Lamarck
·Tongue rolling: both parents heterozygous dominant (Tt × Tt) for one tailed, one not to roll
·Dihybrid cross TTRR × ttrr → F1: TtRr; F2 phenotypic ratio 9:3:3:1; state Law of Independent Assortment

Endocrine System

Q1 MCQ + Q2 + Q3 every year

·ADH deficiency → increased urination (ADH promotes water reabsorption — both A and R true)
·Match glands to functions: adrenal (stress), pituitary (tropic hormones), pancreas (blood sugar), thyroid (basal metabolism), ovary (oestrogen)

Cell Division

Q1 MCQ + Q3 every year

·Phase where spindle fibres disappear: Telophase
·Draw animal cell in Metaphase with 4 chromosomes (chromosomes at equatorial plate)
·Mention two pairs of nitrogenous bases in DNA: A-T and G-C

Nervous System

Q1 MCQ + Q2 every year

·Arachnoid layer speeds nerve impulse transmission: false (myelin sheath does this)
·Caffeine → stimulates adrenal gland → adrenaline; organ stimulated: brain (cerebrum); protective membranes: meninges; sympathetic NS increases adrenaline

Osmosis and Transpiration

Q1 MCQ + Q6 every year

·Turgid cell: turgor pressure = wall pressure (balanced state) — both A and R true
·Label plasmolysed cortical cell: cytoplasm, hypertonic solution, plasma membrane

Photosynthesis

Q1 MCQ + Q3/Q4/Q5 every year

·Optimum temperature for photosynthesis: 25–35°C
·Write overall chemical equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
·Name phytohormone for seedless fruit: Gibberellin; technical term: Parthenocarpy
·Draw experiment to show O₂ released (hydrilla/elodea in water + light)

Pollution

Q1 MCQ + Q3/Q4 every year

·Nuclear plants releasing hot water → thermal pollution
·Two disadvantages of living near airport: noise pollution, air pollution
·Two harmful effects of acid rain: damages buildings, kills aquatic life

Section B — Attempt any 4 of 5 (Questions 3–8, 40 marks)

Each question has 5 parts (1+2+2+2+3 marks pattern).

Circulatory System — Heart and Blood

Section B every year (Q2/Q4)

·Label heart diagram: pericardium, aorta, pulmonary artery, chordae tendineae, coronary arteries
·WBCs: phagocytosis (neutrophils/monocytes); produce antibodies (lymphocytes)

Excretory System

Section B every year (Q5)

·Micturition: process of passing urine; explain reflex pathway
·Differentiate urethra and uterus functions
·Distinguish nephron (structural unit of kidney) from neuron (structural unit of nervous system)

Ear and Balance

Section B every year (Q5/Q6)

·Gymnast loses balance: saccule and utricle (vestibular apparatus/static balance)
·Ear infection causing earache: Eustachian tube connects middle ear to nasopharynx

Plant Physiology — Sequence and Diagrams

Section B every year (Q3/Q4/Q5)

·Sequence: Palisade cells → upper epidermis → cuticle → spongy cells (light path)
·Sequence: Stomach → hepatic portal vein → liver → hepatic vein
·Mention scientific phenomena in labelled tree diagram: transpiration, photosynthesis, absorption

Population and Evolution

Section B every year (Q7/Q8)

·Reason for reduced death rate: medical advances, sanitation, vaccination
·Cro-Magnon: high cranial capacity, developed chin, upright posture, reduced brow ridges
·Vestigial organs: wisdom teeth, vermiform appendix — support Lamarck's disuse theory

Genetics — Dihybrid Cross

Section B every year (Q8)

·TTRR × ttrr → F1: all TtRr (tall red); F2: 9 tall red : 3 tall yellow : 3 dwarf red : 1 dwarf yellow
·State Mendel's Law of Independent Assortment
·Define Allele

Source: All patterns derived from official CISCE ICSE Class 10 board examination papers (2023, 2024, 2025) downloaded from cisce.org. For the actual question papers, view the Science — Biology Previous Year Papers.