🌸 Class 10 Biology — How do Organisms Reproduce? FULL MASTER NOTES
CBSE Board 2026 | Ultra Detailed Notes + Tricks + PYQs + NCERT Points + Diagrams + Board Answers
📖 INTRODUCTION
Reproduction is one of the most important characteristics of living organisms.
It is the process by which organisms produce new organisms similar to themselves.
🌟 WHY IS REPRODUCTION IMPORTANT?
Reproduction is important because:
- It ensures continuity of species.
- It transfers hereditary characters.
- It maintains population.
- It produces variations helpful in evolution.
🌟 TYPES OF REPRODUCTION
| Type | Parents Involved | Gametes |
|---|---|---|
| Asexual reproduction | One | Not formed |
| Sexual reproduction | Two | Formed |
🌱 ASEXUAL REPRODUCTION
Reproduction involving only one parent without fusion of gametes.
🌟 CHARACTERISTICS
- Only one parent needed
- Faster process
- Offspring identical to parent
- No variation
🌟 ADVANTAGES
- Fast multiplication
- Less energy required
- No mate needed
🌟 DISADVANTAGES
- No variation
- Less adaptability
🌟 TYPES OF ASEXUAL REPRODUCTION
- Fission
- Budding
- Fragmentation
- Regeneration
- Spore formation
- Vegetative propagation
🌟 FISSION
Parent organism divides into daughter cells.
TYPES OF FISSION
| Type | Example |
|---|---|
| Binary fission | Amoeba |
| Multiple fission | Plasmodium |
🌟 Binary Fission
One parent divides into two equal daughter cells.
🌟 Binary Fission Diagram
 |
| Binary fission diagram |
🌟 Multiple Fission
One parent produces many daughter cells.
Example:
Plasmodium
🌟 BUDDING
A small outgrowth called bud develops on parent body.
Example:
Yeast, Hydra
🌟 Budding Diagram
🌟 FRAGMENTATION
Body breaks into fragments and each fragment develops into new organism.
Example:
Spirogyra
🌟 REGENERATION
Ability to regrow lost body parts.
Example:
Planaria, Hydra
🌟 IMPORTANT NCERT LINE ⭐
Regeneration is not same as reproduction because all organisms cannot regenerate whole body.
🌟 SPORE FORMATION
Spores are produced inside sporangia.
Example:
Rhizopus
🌟 FEATURES OF SPORES
- Thick wall
- Resistant
- Survive unfavorable conditions
🌟 Spore Formation Diagram
🌟 VEGETATIVE PROPAGATION 🌱
New plants arise from roots, stems or leaves.
🌟 EXAMPLES
| Plant | Vegetative Part |
|---|---|
| Potato | Stem |
| Bryophyllum | Leaf |
| Ginger | Stem |
| Onion | Bulb |
| Sweet potato | Root |
🌟 ADVANTAGES OF VEGETATIVE PROPAGATION
- Faster growth
- Identical plants
- Useful in seedless plants
🌟 ARTIFICIAL VEGETATIVE PROPAGATION
- Cutting
- Layering
- Grafting
- Tissue culture
🌟 TISSUE CULTURE
Technique of growing plants from small tissue pieces in laboratory.
🌸 SEXUAL REPRODUCTION
Reproduction involving fusion of male and female gametes.
🌟 IMPORTANCE OF SEXUAL REPRODUCTION
- Produces variations
- Helps evolution
- Better survival
🌟 PUBERTY ⭐ VERY IMPORTANT
Stage when reproductive organs become mature.
🌟 CHANGES DURING PUBERTY
👦 BOYS
- Beard and moustache growth
- Deep voice
- Broad shoulders
- Hair growth
👧 GIRLS
- Breast development
- Menstruation starts
- Wider hips
🌟 HORMONES RESPONSIBLE
| Hormone | Function |
|---|---|
| Testosterone | Male characters |
| Estrogen | Female characters |
🌟 REPRODUCTIVE HEALTH
State of physical, mental and social well-being related to reproduction.
👨 MALE REPRODUCTIVE SYSTEM
🌟 Male Reproductive System Diagram
🌟 PARTS AND FUNCTIONS
| Part | Function |
|---|---|
| Testes | Produce sperms |
| Scrotum | Maintains low temperature |
| Vas deferens | Transports sperms |
| Seminal vesicle | Provides nourishment |
| Prostate gland | Secretes fluid |
| Urethra | Passage for sperms |
| Penis | Copulatory organ |
🌟 TESTES ⭐
Located outside abdominal cavity because sperms need lower temperature.
🌟 SPERM
Male gamete.
🌟 STRUCTURE OF SPERM
- Head
- Middle piece
- Tail
🌟 FUNCTIONS OF PARTS
| Part | Function |
|---|---|
| Head | Contains nucleus |
| Middle piece | Energy production |
| Tail | Movement |
🌟 SPERM Diagram
👩 FEMALE REPRODUCTIVE SYSTEM
🌟 Female Reproductive System Diagram
🌟 PARTS AND FUNCTIONS
| Part | Function |
|---|---|
| Ovary | Produces ova |
| Fallopian tube | Site of fertilization |
| Uterus | Growth of embryo |
| Cervix | Lower opening of uterus |
| Vagina | Birth canal |
🌟 OVARY
Produces:
- Ovum (egg)
- Estrogen hormone
🌟 OVUM
Female gamete.
🌟 MENSTRUAL CYCLE ⭐ BOARD IMPORTANT
Monthly cycle in females lasting about 28 days.
🌟 EVENTS OF MENSTRUAL CYCLE
- Egg matures
- Ovulation occurs
- Uterus lining thickens
- Fertilization may occur
- If fertilization fails → menstruation
🌟 MENSTRUATION
Shedding of uterine lining with blood.
🌟 MENSTRUAL HYGIENE
- Use clean pads
- Change regularly
- Maintain cleanliness
- Eat healthy food
🌟 OVULATION
Release of mature egg from ovary.
🌟 FERTILIZATION ⭐
Fusion of sperm and ovum.
🌟 SITE OF FERTILIZATION
Fallopian tube.
🌟 ZYGOTE
Single cell formed after fertilization.
🌟 EMBRYO
Developing multicellular structure formed after repeated divisions.
🌟 IMPLANTATION
Attachment of embryo to uterus wall.
🌟 PLACENTA ⭐ VERY IMPORTANT
Disc-like structure connecting mother and embryo.
🌟 FUNCTIONS OF PLACENTA
- Transfers food
- Provides oxygen
- Removes waste
- Transfers nutrients
🌟 GESTATION PERIOD
Time of development of baby in uterus.
In humans:
Approximately 9 months
🌟 PARTURITION
Process of childbirth.
🌟 REPRODUCTION IN FLOWERING PLANTS 🌸
🌸 FLOWER
Reproductive organ of plant.
🌸 Flower Diagram
🌟 PARTS OF FLOWER
| Part | Function |
|---|---|
| Sepals | Protection |
| Petals | Attract insects |
| Stamen | Male part |
| Pistil | Female part |
🌟 STAMEN
Male reproductive organ.
Parts:
- Anther
- Filament
🌟 POLLEN GRAINS
Contain male gametes.
🌟 PISTIL
Female reproductive organ.
Parts:
- Stigma
- Style
- Ovary
🌟 OVULE
Contains female gamete.
🌟 POLLINATION
Transfer of pollen from anther to stigma.
🌟 TYPES OF POLLINATION
| Type | Meaning |
|---|---|
| Self pollination | Same flower |
| Cross pollination | Different flower |
🌟 AGENTS OF POLLINATION
- Wind
- Water
- Insects
🌟 FERTILIZATION IN PLANTS
Fusion of male and female gametes.
🌟 AFTER FERTILIZATION
| Structure | Changes Into |
|---|---|
| Ovary | Fruit |
| Ovule | Seed |
🌟 GERMINATION
Development of seed into seedling.
🔥 MOST IMPORTANT DIFFERENCES
Sexual vs Asexual Reproduction
| Sexual | Asexual |
|---|---|
| Two parents | One parent |
| Variation present | No variation |
| Gametes formed | No gametes |
Male Gamete vs Female Gamete
| Sperm | Ovum |
|---|---|
| Small | Large |
| Motile | Non-motile |
| Tail present | Tail absent |
Self vs Cross Pollination
| Self | Cross |
|---|---|
| Same flower | Different flower |
| Less variation | More variation |
🎯 BOARD LEVEL EXPECTED QUESTIONS WITH ANSWERS
Q1. What is placenta? Mention its functions.
Answer:
Placenta is a special tissue connecting embryo with uterine wall of mother.
Functions:
- Transfers nutrients
- Provides oxygen
- Removes waste products
- Supplies food to embryo
Q2. Why are testes present outside abdominal cavity?
Answer:
Testes are located outside abdominal cavity in scrotum because sperm formation requires temperature lower than body temperature.
Q3. Explain menstruation.
Answer:
If fertilization does not occur, the thick uterine lining breaks down and blood flows out through vagina. This process is called menstruation.
Q4. Differentiate between sexual and asexual reproduction.
| Sexual Reproduction | Asexual Reproduction |
|---|---|
| Two parents involved | One parent involved |
| Gametes formed | Gametes absent |
| Variations present | Variations absent |
Q5. What is fertilization? Where does it occur?
Answer:
Fusion of male and female gametes is called fertilization.
In humans, fertilization occurs in fallopian tube.
🔥 MOST IMPORTANT NCERT LINES
- Variations are useful for survival.
- Testes produce sperms.
- Fertilization occurs in fallopian tube.
- Placenta provides nourishment.
- Flowers are reproductive organs of plants.
🧠SUPER TRICKS
Male Parts:
“TSVUP”
- Testes
- Scrotum
- Vas deferens
- Urethra
- Penis
Female Parts:
“OFUV”
- Ovary
- Fallopian tube
- Uterus
- Vagina
Flower Parts:
“SPSP”
- Sepal
- Petal
- Stamen
- Pistil
✍️ MOST IMPORTANT DIAGRAMS FOR BOARDS
- Male reproductive system
- Female reproductive system
- Sperm structure
- Flower structure
- Binary fission
- Budding
- Spore formation
🎯 EXPECTED QUESTIONS FOR 2026 BOARD
- Draw male reproductive system and label parts.
- Explain menstruation.
- Why are variations important?
- Explain fertilization in humans.
- Explain vegetative propagation.
- Draw flower and label parts.
- Explain pollination.
- What are functions of placenta?
