CBSE Class 10 Science: How do Organisms Reproduce ? | Important Concept-Based Questions

CBSE Class 10 Science: How do Organisms Reproduce? | Important Concept-Based Questions

CBSE Class 10 • Biology • High-yield

How do Organisms Reproduce? — Important Concept-Based Questions (CBSE Class 10)

A clear, exam-focused walkthrough that turns NCERT concepts into board-ready answers. Read on for conceptual explanations, model answers, practice questions and a study plan tailored by BACE IIT JEE.

Practice Questions Model Answers Contact & Admissions

Chapter overview — Why this topic matters

Reproduction is central to biology because it ensures continuity of life. The CBSE Class 10 chapter How do Organisms Reproduce? balances descriptive concepts (like life-cycle diagrams and types of reproduction) with application-based reasoning (variation, evolutionary advantage, reproductive health). For boards, mastering this chapter means being able to: identify reproductive strategies across life forms, explain mechanisms, and apply these ideas in short and long answer formats.

This article expands NCERT essentials into clear concepts and practice-style questions. Use it as a companion to your NCERT book and classroom notes.

Pro tip: Labelled diagrams (flower, human reproductive systems) and precise keywords (zygote, gamete, fertilization, vegetative propagation) often win marks quickly—make them your first revision checkpoint.

1. Asexual reproduction — fast and faithful

Asexual reproduction involves a single parent and produces genetically identical progeny (clones). Because there is no fusion of gametes, genetic variation is minimal. This is advantageous when the environment is stable and resources are plentiful.

Key methods (with simple explanations)

Binary fission: Single-celled organisms (Amoeba) split into two equal parts.
Budding: A new individual grows from a bud on the parent—Hydra, Yeast.
Spore formation: Rhizopus produces spores in sporangia; when released they form new fungi.
Fragmentation: Organism breaks into pieces and each piece regenerates—Spirogyra.
Vegetative propagation: New plants grow from roots, stems, leaves—potato (tubers), bryophyllum (leaf buds).

Concept question: Explain why asexual reproduction is useful for organisms living in stable environments.

Because it is fast and produces many genetically identical offspring adapted to the same environment—no need for energy investment in gamete production or finding mates.

2. Sexual reproduction — source of variation

Sexual reproduction involves two parents and the fusion of gametes (sperm and egg). The resulting genetic recombination creates variation within a population—this variation is the raw material for natural selection and long-term survival in changing environments.

Plants: Flower structure & reproduction

Flowers are the reproductive units of angiosperms. Stamen (anther + filament) produces pollen (male gamete), while the carpel (stigma, style, ovary) houses the ovule (female gamete). Pollination (self or cross) precedes fertilization.

Model explanation — pollination to seed formation (short):

Pollen lands on stigma → pollen tube grows down the style → sperm moves to the ovule → fertilization → zygote forms → embryo within seed develops → seed germinates to produce a plant.

Concept question: Why is cross-pollination generally better for a plant species than self-pollination?

Cross-pollination mixes genetic material from different individuals and increases genetic diversity, which improves adaptability to changing conditions and disease resistance.

3. Human reproduction — essentials for the board

Human reproduction is sexual and involves a coordinated interaction between the male and female reproductive systems. For CBSE, be able to:

Label the diagram of male and female reproductive systems.
Explain gamete production (spermatogenesis, oogenesis), site of fertilization, and development of embryo.

Where fertilization occurs

Fertilization takes place in the fallopian tube (also called uterine tube). After fertilization, the zygote divides and reaches the uterus for implantation.

Reproductive health — short note

Reproductive health covers hygiene, contraception, and awareness. For CBSE, understand the role of contraceptives in preventing unwanted pregnancies and sexually transmitted infections (STIs).

4. Important concept-based questions (with scoring hints)

The following questions are curated for board-level preparation. Attempt them as practice and then check the model answers below.

Short-answer (2–3 marks)

Define reproduction. Why is it necessary for organisms?
Give two differences between sexual and asexual reproduction.
What is a seed? Describe briefly its components.
What is vegetative propagation? Give two advantages.
Where does fertilization take place in human females?

Long-answer (5 marks)

Describe the male reproductive system with labeled diagram. Mention the function of testes and vas deferens.
Explain the process of pollination and double fertilization in flowering plants.
Discuss how variation arises in sexually reproducing organisms and why it is important for survival.

HOTS / Application (5 marks)

If a species reproduces only by asexual means, how will that affect its ability to survive long-term environmental changes? Explain.
Suggest two methods by which farmers can reproduce plants exhibiting a desirable trait—justify your choices.

5. Model answers & scoring tips

Q1: Define reproduction. Why is it necessary?

Model answer (2 marks): Reproduction is the biological process by which organisms produce offspring of their own kind. It is necessary to maintain a species, transmit hereditary information and create genetic variation (in sexual reproduction) that helps adaptation.

Q6: Describe the male reproductive system.

Model answer (5 marks — include labelled diagram):

Testes: Paired organs producing sperm and testosterone.
Epididymis: Stores sperm; site for sperm maturation.
Vas deferens: Conveys sperm during ejaculation.
Seminal vesicles and prostate: Add seminal fluid to nourish and transport sperm.
Urethra and penis: Passageway for semen and urine; penis deposits semen in female reproductive tract.

Scoring tip: A clear, labelled diagram plus 3–4 short points gives full marks.

Q8: Why is variation important?

Model answer (5 marks): Variation results from sexual reproduction, mutations and recombination of genes during gamete formation. It produces individuals with different characteristics; some may survive under changed conditions, ensuring long-term survival of the species. Use an example (e.g., disease resistance in plants) to illustrate.

6. Exam strategy & 2‑week study plan

Follow this focused plan to revise the chapter and practice answers efficiently.

2-week plan (recommended)

Days 1–3: Read NCERT thoroughly; annotate diagrams and underline key terms.
Days 4–6: Practice short-answer questions and label diagrams from memory.
Days 7–9: Attempt long questions and HOTS; time yourself for 20–30 minutes per long answer.
Days 10–12: Solve past 5 years’ board questions on reproduction + mark scheme analysis.
Days 13–14: Quick revision: formulas, keywords, and 10 most-likely questions.

Quick score-boosting tips

Always draw neat, labelled diagrams — they fetch marks fast.
Use bullet points for 2–3 mark questions.
Start with definitions, then explanation with an example.
For 5-mark answers, use subheadings and end with a conclusion sentence.

7. Quick practice set (answer in 10–20 minutes)

List three differences between spores and seeds.
Explain bud formation in Hydra with a labelled sketch.
What is double fertilization? Why is it unique to angiosperms?
How can vegetative propagation help horticulture? Provide two examples.

Model short answers (hints):

Spores are unicellular; seeds are multicellular with nutritive tissue.
Budding: small outgrowth forms on the parent, develops and detaches — draw parent with bud labeled.
Double fertilization: one sperm fuses with egg (zygote); other fuses with polar nuclei (endosperm) — provides nutrition to embryo.
Vegetative propagation: ensures true-to-type plants; examples: grafting in fruit trees, tuber planting in potatoes.

8. FAQs students ask

Do I need to memorise the entire NCERT text?: Understand and memorise key definitions, diagrams and processes. Paraphrase explanations rather than rote learning; examiners reward clarity over verbatim recall.
How many diagrams should I practise?: At least 6 diagrams: male system, female system, flower structure, seed, life cycle of Rhizopus/Amoeba/Spawning plant — practice until you can draw them in under 3 minutes.
Can I use examples not in NCERT?: Yes — but use standard, widely accepted examples (Hydra, Yeast, Rhizopus, Bryophyllum, Potato, Mango grafting). Ensure they illustrate the concept.

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