MP Board Class 10 Science Ch7: How do Organisms Reproduce?

MP Board Class 10 Science Chapter 7: How do Organisms Reproduce? Important Questions — This chapter explores the fascinating world of reproduction in living organisms — from the simplest fission in amoeba to the complex reproductive systems in humans. Covering asexual reproduction, sexual reproduction in flowering plants, human reproductive system, and reproductive health, this chapter carries 6–8 marks in the MP Board Class 10 Science exam. Mastering these important questions will help you secure full marks in the board exam 2027.

🔬 1. Asexual Reproduction — Types and Examples

Q1. What is reproduction? Why is it essential for organisms?

Answer: Reproduction is the biological process by which living organisms produce offspring of their own kind. It is essential because:

• It ensures the continuity of species from one generation to the next
• It maintains the population of species on Earth
• It introduces genetic variations that help species adapt to changing environments
• Without reproduction, a species would become extinct

Q2. Differentiate between asexual and sexual reproduction.

Q3. Explain binary fission with an example. How is it different from multiple fission?

Answer: Binary fission is a type of asexual reproduction in which the parent cell divides into two equal daughter cells. The nucleus divides first (karyokinesis), followed by the cytoplasm (cytokinesis). Example: Amoeba, Paramecium, bacteria.

Q4. What is budding? Name an organism that reproduces by this method.

Answer: Budding is a type of asexual reproduction in which a small outgrowth (bud) develops on the parent body, grows, and eventually detaches to form a new individual. The bud contains a nucleus and cytoplasm from the parent. Example: Hydra (a freshwater organism) and Yeast (a unicellular fungus). In Hydra, the bud develops as a small projection, grows tentacles, and finally separates from the parent.

Q5. What is regeneration? Give examples.

Answer: Regeneration is the ability of an organism to regrow lost or damaged body parts. In some organisms, even a broken fragment can develop into a complete individual. Examples:

• Planaria (flatworm) — if cut into pieces, each piece can regenerate into a complete worm
• Hydra — can regenerate lost tentacles and foot
• Lizard — can regrow its tail (limited regeneration)
• Starfish — can regenerate lost arms

Q6. Differentiate between fragmentation and regeneration.

Q7. What is vegetative propagation? Give some artificial methods.

Answer: Vegetative propagation is a type of asexual reproduction in plants where new plants grow from vegetative parts (roots, stems, leaves) of the parent plant. It does not involve seeds or spores. Artificial methods include:

• Cutting: A stem cutting is planted in soil. Example: Rose, Sugarcane, Grapes
• Layering: A branch is bent to the ground and covered with soil. Example: Jasmine, Bougainvillea
• Grafting: Stem of one plant (scion) is joined to the root system of another (stock). Example: Mango, Apple, Rose
• Tissue culture: Growing plants from small tissue pieces in a nutrient medium. Example: Orchids, Banana

🌸 2. Sexual Reproduction in Flowering Plants

Q8. Draw a labelled diagram of the longitudinal section of a flower and explain the functions of each part.

Answer: A flower’s longitudinal section shows the following parts:

Q9. Explain the process of pollination. Differentiate between self-pollination and cross-pollination.

Answer: Pollination is the transfer of pollen grains from the anther (male part) to the stigma (female part) of a flower. It is the first step in sexual reproduction in flowering plants.

Q10. What are the agents of pollination? Explain with examples.

Answer: The main agents of pollination are:

• Wind (Anemophily): Light, dry pollen carried by wind. Example: Corn, Wheat, Grass. Flowers are small, inconspicuous, without scent/nectar.
• Insects (Entomophily): Bees, butterflies, moths carry pollen. Example: Sunflower, Rose. Flowers are large, colourful, fragrant, with nectar.
• Birds (Ornithophily): Sunbirds, hummingbirds. Example: Bottlebrush, Hibiscus. Flowers are bright red/orange, tubular, with abundant nectar.
• Water (Hydrophily): Pollen floats on water surface. Example: Vallisneria, Hydrilla, Water lily.

Q11. Explain fertilization in plants. What happens after fertilization?

Answer: Fertilization in plants is the fusion of male gamete (from pollen grain) with female gamete (in ovule) to form a zygote. The process:

1. After pollination, a pollen tube grows from the pollen grain through the style towards the ovary
2. The pollen tube carries two male gametes (nuclei) into the ovule
3. One male gamete fuses with the egg cell → forms zygote (2n) → develops into embryo
4. The other male gamete fuses with two polar nuclei → forms triploid nucleus (3n) → develops into endosperm (food for embryo)

After fertilization:

• Ovule → Seed
• Ovary → Fruit
• Zygote → Embryo
• Integuments of ovule → Seed coat
• Petal, sepal, stamen → Wither and fall off

🧬 3. Human Male Reproductive System

Q12. Draw a labelled diagram of the human male reproductive system and explain the functions of each part.

Answer: The human male reproductive system consists of the following parts:

👩 4. Human Female Reproductive System

Q13. Draw a labelled diagram of the human female reproductive system and explain the functions of each part.

Answer: The human female reproductive system consists of:

Q14. What is menstruation? Explain the menstrual cycle.

Answer: Menstruation is the monthly shedding of the uterine lining (endometrium) when fertilization has NOT occurred. The menstrual cycle is approximately 28 days and includes:

• Menstrual phase (Days 1-5): Uterine lining breaks down and is discharged as blood and mucus through the vagina
• Follicular phase (Days 6-13): New egg matures in ovary; uterine lining rebuilds
• Ovulation (Day 14): Mature egg is released from the ovary into the oviduct
• Luteal phase (Days 15-28): Uterine lining thickens further; if fertilization doesn’t happen, the cycle repeats

Importance: Menstruation prepares the uterus for pregnancy each month. It typically begins at puberty (menarche, around age 10-15) and ends around age 45-50 (menopause).

Q15. Explain the process of fertilization and implantation in humans.

Answer: Fertilization in humans occurs in the oviduct (Fallopian tube). During intercourse, semen containing millions of sperm is released into the vagina. Sperm swim through the cervix and uterus into the oviduct. One sperm fuses with the egg to form a zygote. The zygote divides repeatedly (cleavage) to form a ball of cells called morula, which becomes a blastocyst. Implantation occurs when the blastocyst attaches to the thickened uterine lining (endometrium) about 6-7 days after fertilization. This marks the beginning of pregnancy (gestation period ≈ 9 months or 40 weeks in humans).

🏥 5. Reproductive Health and Contraception

Q16. What is contraception? Explain different methods of contraception.

Answer: Contraception refers to methods used to prevent pregnancy. Different methods include:

Q17. What are sexually transmitted diseases (STDs)? How can they be prevented?

Answer: STDs are infections that spread through sexual contact. Common STDs include:

• Bacterial: Gonorrhea, Syphilis, Chlamydia — treatable with antibiotics
• Viral: HIV/AIDS, Genital herpes, HPV, Hepatitis B — manageable but not curable
• Protozoan: Trichomoniasis — treatable with medication

Prevention: Use condoms, have mutually faithful relationships, avoid multiple partners, get regular health checkups. HIV can be managed with antiretroviral therapy (ART) but has no cure.

Q18. What is IVF? Explain its significance.

Answer: IVF (In Vitro Fertilization) is an assisted reproductive technology where fertilization of egg and sperm occurs outside the body in a laboratory dish (test tube). The resulting embryo is then implanted into the mother’s uterus. It is used when:

• Fallopian tubes are blocked or damaged
• Male infertility (low sperm count)
• Older age or unexplained infertility

Significance: Helps millions of infertile couples worldwide to have biological children. The first IVF baby (Louise Brown) was born in 1978. In India, Dr. Subhash Mukhopadhyay pioneered the first IVF baby in 1978 (just months after Louise Brown).

📝 6. Multiple Choice Questions (1 Mark Each)

MCQs are frequently asked in MP Board exams from this chapter. Here are 10 important MCQs with answers marked.

1. Which of the following is a mode of asexual reproduction?
   (a) Binary fission ✓   (b) Fertilization   (c) Pollination   (d) Implantation
2. The male reproductive organ in a flower is called:
   (a) Pistil   (b) Stamen ✓   (c) Ovary   (d) Sepal
3. In humans, fertilization occurs in the:
   (a) Uterus   (b) Vagina   (c) Oviduct ✓   (d) Ovary
4. The number of chromosomes in a human zygote is:
   (a) 23   (b) 46 ✓   (c) 23 pairs ✓   (d) 48
5. Which contraceptive method also protects against STDs?
   (a) Copper-T   (b) Oral pills   (c) Condom ✓   (d) Vasectomy
6. Which hormone is responsible for the development of male secondary sexual characteristics?
   (a) Estrogen   (b) Progesterone   (c) Testosterone ✓   (d) Insulin
7. Vegetative propagation in potato occurs through:
   (a) Root   (b) Stem (tuber) ✓   (c) Leaf   (d) Seed
8. The part of the flower that develops into a fruit is:
   (a) Ovule   (b) Ovary ✓   (c) Pollen grain   (d) Stigma
9. Which organism reproduces by budding?
   (a) Amoeba   (b) Planaria   (c) Hydra ✓   (d) Spirogyra
10. What is the gestation period in humans?
    (a) 28 days   (b) 9 months ✓   (c) 6 months   (d) 12 months

✏️ 7. Very Short & Short Answer Questions (2–4 Marks)

1. What is DNA copying? Why is it important in reproduction?
   DNA (Deoxyribonucleic Acid) copying is the process of making an identical copy of the DNA molecule before cell division. It is important because it ensures that genetic information is faithfully transferred from parent to offspring, maintaining species-specific characteristics while allowing for minor variations that drive evolution. (2 marks)
2. What are the advantages of vegetative propagation?
   (i) Plants mature faster — they bear flowers and fruits earlier than seed-grown plants. (ii) Desirable traits are preserved exactly (identical to parent). (iii) Seedless fruits (banana, grapes, orange) can be propagated. (iv) It is useful for plants that produce few or non-viable seeds. (2 marks)
3. Why is variation beneficial to the species but not necessarily for the individual?
   Variation introduces genetic diversity in a population, which increases the chances of survival under changing environmental conditions (disease, climate change, predators). While a specific variation may not benefit a single individual (it could even be harmful), the presence of varied traits in the population ensures that at least some individuals survive environmental challenges, preventing species extinction. (3 marks)
4. Differentiate between viviparous and oviparous organisms. Give one example of each.
   Viviparous: Give birth to live young; embryo develops inside mother’s body; receives nutrition from mother. Example: Human, Dog, Cow. Oviparous: Lay eggs; embryo develops outside mother’s body; nutrition from egg yolk. Example: Hen, Frog, Snake, Crocodile. (3 marks)
5. What is the role of the seminal vesicles and prostate gland in the male reproductive system?
   These accessory glands add fluid to the sperm to form semen. The fluid provides nutrition (fructose) for sperm energy, neutralizes the acidic environment of the female vagina, and helps sperm swim/move. Without these secretions, sperm would not survive or swim effectively inside the female reproductive tract. (3 marks)
6. What is the function of the placenta in the human female reproductive system?
   The placenta is a specialized tissue that connects the developing fetus to the uterine wall. It serves as a lifeline — providing oxygen and nutrients (glucose, amino acids) from mother to fetus, removing waste products (CO₂, urea) from fetal blood, and producing hormones (hCG, progesterone) that maintain pregnancy. The placenta is expelled after birth (as the afterbirth). (3 marks)
7. Why does menstruation occur? What happens if fertilization does not take place?
   Menstruation occurs because the thickened uterine lining (endometrium), prepared to receive a fertilized egg, is shed when fertilization does NOT occur. If fertilization doesn’t happen, the corpus luteum degenerates, progesterone levels drop, and the uterine lining breaks down and is discharged as menstrual blood through the vagina. This cycle repeats every ~28 days. (3 marks)
8. Describe the process of reproduction in Hydra.
   Hydra reproduces by budding. A small outgrowth (bud) develops on the parent Hydra’s body through repeated cell division. The bud grows, develops tentacles and a mouth, and eventually detaches from the parent to live as an independent organism. This is a form of asexual reproduction — offspring are genetically identical to the parent. Under favourable conditions, Hydra also reproduces sexually by producing gametes. (3 marks)
9. What is the importance of the scrotum in human males?
   The scrotum is a sac-like structure that holds the testes outside the body cavity. It maintains the testes at a temperature 2-3°C lower than body temperature (about 35°C), which is essential for proper sperm production (spermatogenesis). The scrotum contracts (pulls testes closer to body) in cold weather and relaxes (moves them away) in warm conditions to regulate temperature. (2 marks)
10. What is the difference between a zygote and an embryo?
    Zygote: The single-celled fertilized egg formed by the fusion of sperm and egg. It is the first cell of a new individual. Embryo: The multicellular stage that develops from the zygote after repeated cell divisions. The embryo eventually develops into a fetus. In humans, the zygote stage lasts ~24 hours; the embryo stage lasts from week 2 to week 8 of pregnancy. (2 marks)

📖 8. Long Answer Questions (5–6 Marks)

Q1. Explain the process of reproduction in Amoeba by binary fission. How does it differ from multiple fission?

Answer: Binary fission in Amoeba: Amoeba, a unicellular protozoan, reproduces by binary fission. The process begins with the nucleus elongating and dividing into two daughter nuclei (karyokinesis). A constriction forms in the cytoplasm, which deepens and divides the cell into two equal halves (cytokinesis). Each half receives one nucleus and the necessary cytoplasm to form a complete organism. Under favourable conditions, Amoeba can divide every 2-3 hours. Multiple fission occurs in Amoeba under unfavourable conditions (e.g., lack of food, drying). The Amoeba forms a protective cyst around itself, and its nucleus divides repeatedly into many daughter nuclei. Each nucleus gets surrounded by a small amount of cytoplasm, forming multiple daughter cells (amoebulae). When conditions improve, the cyst breaks open, releasing many Amoebae at once. Key difference: Binary fission produces 2 offspring quickly, while multiple fission produces many offspring after a resting period.

Q2. Describe the process of sexual reproduction in flowering plants, starting from pollination to seed formation.

Answer: The process of sexual reproduction in flowering plants involves the following steps:

Step 1 — Pollination: Pollen grains from the anther are transferred to the stigma of a flower. This can be self-pollination (same flower) or cross-pollination (different flower). Agents include wind, insects, birds, and water.

Step 2 — Germination of pollen grain: A pollen grain lands on the stigma and absorbs nutrients and moisture. It germinates by growing a pollen tube through the style towards the ovary. The pollen tube carries two male gametes (nuclei).

Step 3 — Fertilization (Double Fertilization): The pollen tube enters the ovule through the micropyle. One male gamete fuses with the egg cell to form a diploid zygote (2n). The second male gamete fuses with two polar nuclei to form a triploid nucleus (3n). This is called double fertilization — unique to flowering plants.

Step 4 — Post-fertilization changes: The zygote develops into an embryo. The triploid nucleus develops into endosperm (nutritive tissue). The ovule transforms into a seed (with seed coat from ovule integuments). The ovary develops into a fruit. Other flower parts (petals, sepals, anthers, stigma) wither and fall off.

Step 5 — Seed dispersal and germination: Seeds are dispersed by wind, water, animals, or explosive mechanisms. Under suitable conditions, the seed germinates to form a new plant.

Q3. Describe the human male reproductive system with the help of a labelled diagram. Explain the functions of the testes, vas deferens, and prostate gland.

Answer: The human male reproductive system is designed to produce, store, and deliver sperm for fertilization. It consists of primary and accessory organs.

Testes: These are a pair of oval-shaped organs located in the scrotum outside the body cavity. They produce sperm (male gametes) through a process called spermatogenesis, which requires a temperature 2-3°C below body temperature. Testes also secrete the male hormone testosterone, which regulates sperm production, secondary sexual characteristics (deep voice, facial hair, broad shoulders), and male behaviour.

Vas deferens: This is a long muscular tube that carries sperm from the epididymis (where sperm are stored and matured) to the urethra. During ejaculation, peristaltic contractions of the vas deferens propel sperm forward. Vasectomy (male sterilization) involves cutting and tying the vas deferens to prevent sperm from reaching the urethra.

Prostate gland: This is a walnut-sized gland that surrounds the urethra below the bladder. It secretes a thin, alkaline fluid that forms part of the semen (about 30% of semen volume). The fluid neutralizes the acidic environment of the female vagina, protects sperm from damage, and provides nutrients that help sperm swim. The prostate’s secretions also contain enzymes that help liquefy semen after ejaculation, freeing sperm to swim toward the egg.

Other important structures: The seminal vesicles add fructose-rich fluid for sperm energy; the epididymis stores and matures sperm (~20 days); the urethra is the common passage for both semen and urine; the penis delivers semen into the female reproductive tract. The entire system works under the control of hormones — FSH (follicle-stimulating hormone), LH (luteinizing hormone), and testosterone.

📋 Previous Year Questions (2017–2026)

The following questions have appeared in MP Board Class 10 Science exams from this chapter over the past 8 years.

❓ Frequently Asked Questions

Q1. How many marks does Chapter 7 carry in the MP Board Class 10 Science exam?

Chapter 7 typically carries 6-8 marks in the MP Board Class 10 Science board exam. It has significant weightage, especially diagram-based questions (human reproductive systems, flower structure) and comparison-based questions (asexual vs sexual reproduction, binary vs multiple fission).

Q2. Is the diagram of the human reproductive system important for the MP Board exam?

Yes, labelled diagrams of both male and female reproductive systems are VERY frequently asked in MP Board exams — appearing almost every 2-3 years. These are typically 5-mark questions. Practice drawing clean, properly labelled diagrams with all parts clearly indicated.

Q3. What is the difference between fission and fragmentation?

Fission occurs in unicellular organisms where the entire cell divides into two (binary) or many (multiple) daughter cells. Fragmentation occurs in multicellular organisms where the body breaks into fragments, each of which grows into a complete organism. Fission = cell divides; Fragmentation = body breaks into pieces.

Q4. Why is DNA copying considered an essential part of reproduction?

DNA copying (replication) is the molecular basis of reproduction. It ensures the genetic blueprint is accurately transferred to offspring, maintaining species identity. However, minor variations during DNA copying introduce genetic diversity, which is essential for evolution and adaptation.

Q5. What are the advantages of sexual reproduction over asexual reproduction?

Sexual reproduction produces offspring with genetic variation due to the mixing of DNA from two parents. This variation helps species adapt to changing environments, survive diseases, and evolve. Asexual reproduction produces clones that are all equally vulnerable to threats. Sexual reproduction also allows for the elimination of harmful mutations.

Q6. What is double fertilization? Which plants show this phenomenon?

Double fertilization is a unique process in flowering plants (angiosperms) where two male gametes participate in two separate fusion events: one fuses with the egg cell (forming zygote, 2n), and the other fuses with two polar nuclei (forming triploid endosperm, 3n). It was discovered by Nawaschin in 1898.

Q7. How do oral contraceptive pills prevent pregnancy?

Oral contraceptive pills contain synthetic hormones (estrogen and progesterone) that prevent ovulation — the release of eggs from the ovaries. They also thicken cervical mucus, making it difficult for sperm to enter the uterus, and alter the uterine lining to prevent implantation. They are about 99% effective when taken correctly.

Q8. What is the difference between self-pollination and cross-pollination?

In self-pollination, pollen from the same flower or another flower on the same plant lands on the stigma — no external agent needed. In cross-pollination, pollen from one plant is transferred to the stigma of another plant of the same species — requires agents like wind, insects, or birds. Cross-pollination produces more genetic variation.

Q9. Can an organism like Planaria reproduce through regeneration?

Yes, Planaria can reproduce through regeneration, which is a form of asexual reproduction. When a Planaria is cut into pieces, each fragment (containing neoblast cells) can regenerate into a complete organism. This is both a form of reproduction AND repair — the same process serves both purposes in Planaria.

Q10. What is the role of the hormone testosterone in the male body?

Testosterone is the primary male sex hormone produced by the testes (Leydig cells). It regulates sperm production (spermatogenesis), controls the development of male secondary sexual characteristics during puberty (deep voice, facial/body hair, muscle growth, broad shoulders), influences libido (sex drive), and maintains male reproductive tissues.

Q11. What are the different types of asexual reproduction found in animals?

The main types are: (1) Binary fission — Amoeba, Paramecium (2) Multiple fission — Plasmodium (3) Budding — Hydra, Yeast (4) Fragmentation — Planaria (5) Regeneration — Planaria, Starfish (6) Spore formation — Fungi, some algae. Each type produces genetically identical offspring (clones).

Q12. What precautions should be taken to avoid STDs?

Use condoms (which protect against both pregnancy and STDs), maintain mutually faithful relationships with an uninfected partner, avoid multiple sexual partners, get regular health screenings, and seek immediate medical attention if any symptoms appear. Vaccines are available for HPV and Hepatitis B. Education and awareness are the best prevention.