CBSE · Class 10 · Science · Chapter 7
How do Organisms Reproduce? — Class 10 Science (CBSE) explained
- Board exam 2026-27
- 4 lessons
- 32 scenes
- About 24 min
- Updated
Quick answer
How do Organisms Reproduce? is Chapter 7 of CBSE Class 10 Science. It covers multiple fission and yeast budding, budding in Hydra, spore formation, meiosis and gametes, flower anatomy and pollination versus fertilisation. AI Lessons teaches it in 4 narrated lessons (about 24 minutes) with an AI tutor and board-pattern practice.
What you’ll learn
Lesson 1: DNA Copying, Variation and Simple Reproductive Modes
6 min- Reproduction Begins with a DNA Copy
- Why Variation Matters for a Species
- Prepare to Compare Yeast and Bread Mould
- Binary Fission Depends on Body Design
- Many Daughter Cells or a Small Bud
- Fragmentation Works with Simple Organisation
- Regeneration Requires Organised Development
- A Hydra Bud Becomes Independent
Lesson 2: Plant Propagation and the Basis of Sexual Reproduction
5 min- New Plants from Vegetative Parts
- Look for Buds in Potato and Bryophyllum
- Compare Money-plant Portions Carefully
- Tissue Culture: From Cells to PlantletsNot assessed
- Rhizopus Reproduces through Spores
- Sexual Reproduction Combines Variations
- Germ-cells Restore the DNA Content
Lesson 3: Flowering Plants and Sexual Maturation
5 min- Identify the Reproductive Parts of a Flower
- Pollination Is Transfer, Fertilisation Is Fusion
- The Pollen Tube Reaches the Ovary
- An Ovule Becomes a Seed, an Ovary Becomes a Fruit
- Germination Reveals the Future Plant
- Puberty Is More than General Growth
- Puberty Changes Differ between People
Lesson 4: Human Reproduction, Reproductive Health and Practice
8 min- Sperm Formation and Delivery
- Egg Formation and the Female Reproductive System
- Fertilisation and Implantation Occur in Different Places
- The Placenta Supports the Developing Embryo
- Why Menstruation Occurs
- Reproductive Health Includes Readiness and Infection Prevention
- Contraception: Barriers and Hormonal Methods
- Contraception: Devices and Surgical Blocks
- Reproduction Also Raises Social Questions
- Recap: Connect the Processes and Practise
Key concepts
- Multiple fission and yeast budding
- The important distinction is many daughter cells at the same time, rather than two.
- Budding in Hydra
- The defining sequence is outgrowth, development, maturation and separation from the parent.
- Spore formation
- The thread-like structures associated with the bread mould Rhizopus are called hyphae.
- Meiosis and gametes
- The germ-cell containing stored food is the female gamete.
- Flower anatomy
- The reproductive parts of angiosperms are located in flowers.
- Pollination versus fertilisation
- Transfer from one flower to another is cross-pollination. Wind, water or animals can achieve this transfer between flowers.
- Reproductive health and readiness
- Sexual maturation is gradual and occurs while general growth continues.
- Devices and surgical contraception
- Surgical methods are safe in the long run, but improperly performed surgery can cause infections and other problems.
Exam focus
- Board exam
- CBSE assesses this chapter in the 2026-27 year-end board examination.
- Syllabus
- Reproduction: Reproduction in animals and plants (asexual and sexual) reproductive health - need and methods of family planning. Safe sex vs HIV/AIDS. Child bearing and women's health.
- Not assessed
- These parts go beyond the 2026-27 syllabus and are taught for understanding only: Tissue Culture: From Cells to Plantlets.
- Paper pattern
- 80 marks, 3 hours, 39 questions in three sections (A Biology, B Chemistry, C Physics); internal assessment 20. Units: I Chemical Substances 25, II World of Living 25, III Natural Phenomena 12, IV Effects of Current 13, V Natural Resources 5.
- Question style
- About 50% of board questions are competency-focused: case-based, source-based, integrated, data interpretation, situational and application-oriented.
- Practice in the app
- 109 board-pattern questions with marking schemes: 30 multiple choice (1 mark), 14 assertion–reason (1 mark), 22 very short answer (2 marks), 24 short answer (3 marks), 6 long answer (5 marks) and 13 case-based (4 marks).
Sample questions with marking points
Board-pattern questions from the AI Lessons practice set for this chapter. The marking points show what an examiner looks for; full model answers are in the app.
Very short answer2 marks
An adolescent says, 'Puberty means only becoming taller.' Correct this statement and give one puberty-related physical change common to boys and girls.
Marking points
- Distinguishes general growth from puberty by identifying puberty as maturation of reproductive tissues during adolescence.1
- Any one common change: thick hair in the armpits or genital area, oily skin, or pimples.1
Short answer3 marks
In an organism with a complex body design, one germ-cell is small and motile, while the other is large and contains food stores. Identify each germ-cell and explain why the food stores are important after their fusion.
Marking points
- Identifies the small, motile germ-cell as the male gamete.1
- Identifies the large germ-cell containing food stores as the female gamete.1
- Food stores supply energy for the zygote's growth and development into an organism with specialised tissues and organs.1
Long answer5 marks
Trace the events from sperm entry into the vagina to implantation of an embryo. Describe the location and structure of the placenta and explain its exchange functions. State the approximate development period and the muscular action responsible for birth.
Marking points
- States that sperms enter through the vagina and travel upwards to the fallopian tube or oviduct.0.5
- States that sperm and egg fuse there to form a zygote.0.5
- States that the zygote divides to form an embryo.0.5
- States that the embryo is implanted in the uterine lining.0.5
- Describes the placenta as a disc embedded in the uterine wall.0.5
- Describes villi on the embryo's side and surrounding blood spaces on the mother's side, providing a large surface area.0.5
- States that glucose and oxygen pass from the mother's blood to the embryo through the placenta.0.5
- States that wastes pass from the embryo into the mother's blood through the placenta.0.5
- States an approximate development period of nine months.0.5
- Identifies rhythmic contractions of uterine muscles as the mechanism of birth.0.5
Frequently asked questions
What does How do Organisms Reproduce? cover in Class 10 Science?
It covers multiple fission and yeast budding, budding in Hydra, spore formation, meiosis and gametes, flower anatomy and pollination versus fertilisation. AI Lessons teaches it in 4 lessons: DNA Copying, Variation and Simple Reproductive Modes, Plant Propagation and the Basis of Sexual Reproduction, Flowering Plants and Sexual Maturation and Human Reproduction, Reproductive Health and Practice.
Is How do Organisms Reproduce? in the CBSE Class 10 board exam?
Yes. CBSE assesses How do Organisms Reproduce? in the 2026-27 year-end board examination. 1 short part goes beyond the syllabus and is marked as not assessed.
Which feature of reproduction explains why two surviving daughter cells may be similar but not absolutely identical?
The chemical reactions involved in DNA copying are not absolutely reliable. Small variations can arise because DNA-copying reactions are not absolutely reliable.
At which stage does a Hydra bud become a new independent individual?
When the fully mature bud detaches from the parent. A Hydra bud develops into a tiny individual and detaches when fully mature.
What are hyphae?
The thread-like structures associated with the bread mould Rhizopus are called hyphae.
What is the germ-cell containing stored food?
The germ-cell containing stored food is the female gamete.
What is the stamen?
The stamen is the male reproductive part and produces yellowish pollen grains. The central pistil is the female reproductive part.
How does AI Lessons teach How do Organisms Reproduce??
As 4 narrated, animated lessons (32 scenes, about 24 minutes in all), with an AI tutor that knows the step you are on and board-pattern practice with marking schemes. The full lessons open after sign-in on an AI Lessons account.
Watch the full lesson
How do Organisms Reproduce?, as a narrated, animated lesson
4 lessons · 32 animated scenes · about 24 minutes, with an AI tutor that knows the step you are on and 109 board-pattern questions with marking schemes.
Lessons open after sign-in. A parent or guardian holds the account and adds each child.