What is the difference between asexual and sexual reproduction?

Asexual reproduction involves only one parent, produces offspring that are genetically identical to the parent (clones), and does not involve fusion of gametes. It is fast, simple, and energy-efficient. Examples include binary fission in Amoeba, budding in Hydra and yeast, fragmentation in Planaria, and spore formation in Rhizopus (bread mould). Sexual reproduction involves two parents, requires formation and fusion of male and female gametes, and produces genetically diverse offspring. This diversity is important for adaptation and evolution. Sexual reproduction is more complex and energy-intensive. Examples include human reproduction, flowering plants, and most animals. The key advantage of sexual reproduction is genetic variation in the offspring, which increases the species' ability to survive changing environments.

How does reproduction occur in flowering plants?

Flowering plants reproduce sexually through their flowers. The flower contains male reproductive parts (stamens with pollen grains containing male gametes) and female reproductive parts (pistil with ovary containing ovules with female gametes). Pollination is the transfer of pollen from the anther to the stigma of the same or another flower, carried by wind, insects, water, or birds. After pollination, pollen germinates and a pollen tube grows down through the style to the ovary. The male gamete travels through the tube and fuses with the female gamete (egg) in the ovule — this is fertilisation. After fertilisation, the ovule develops into a seed containing the embryo, and the ovary wall develops into the fruit. The seed can germinate under suitable conditions to produce a new plant.

What are the various methods of asexual reproduction in animals and plants?

In animals, asexual reproduction occurs through binary fission (Amoeba and Paramecium split into two equal halves), budding (Hydra forms a small outgrowth that breaks off to form a new organism), and regeneration (Planaria can regenerate a whole organism from a cut piece due to cells called neoblasts). In plants, vegetative propagation is common — new plants form from roots (sweet potato), stems (potato tubers, ginger), or leaves (Bryophyllum). Budding also occurs in yeast. Spore formation is seen in fungi and lower plants — spores are light, can travel long distances, and germinate in suitable conditions. Tissue culture is a modern artificial technique where small pieces of plant tissue are grown in nutrient media under sterile conditions to produce many identical plants quickly.

What changes occur in the human body during puberty?

Puberty is the stage when the body undergoes significant physical and hormonal changes that mark the beginning of reproductive maturity. In boys, testosterone secreted by the testes causes the voice to become deeper, growth of facial and body hair, increase in height, broadening of shoulders, and development of the testes and penis. Sperm production begins. In girls, oestrogen from the ovaries causes breast development, widening of hips, growth of pubic and underarm hair, and the beginning of the menstrual cycle. In both sexes, there is increased growth of body hair, development of sweat glands, and acne due to oil gland activity. Emotional changes also occur. Puberty typically begins earlier in girls (10–12 years) than in boys (12–14 years) and marks sexual maturation.

What is the menstrual cycle and what happens during it?

The menstrual cycle is a monthly cycle of hormonal and physical changes in females of reproductive age, lasting about 28 days on average. It prepares the body for possible pregnancy. During the first phase, the uterine lining (endometrium) breaks down and is shed as menstrual flow (menstruation), lasting 3–5 days. In the follicular phase, a follicle in the ovary matures and oestrogen causes the endometrium to rebuild. Around day 14, ovulation occurs — the mature egg is released from the ovary. During the luteal phase, the ruptured follicle forms the corpus luteum which secretes progesterone to maintain the endometrium. If the egg is not fertilised, the corpus luteum degenerates, progesterone levels fall, and the endometrium sheds again, beginning the next cycle. Pregnancy occurs if fertilisation takes place.

NCERT Solutions for Class 10 Science Chapter 7 How Do Organisms Reproduce

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NCERT Solutions for Class 10 Science Chapter 7: How Do Organisms Reproduce

Reproduction is one of the most fundamental processes of life, ensuring the continuity of species from one generation to the next. NCERT Solutions for Class 10 Science Chapter 7 — How Do Organisms Reproduce covers everything from simple binary fission in bacteria to complex sexual reproduction in flowering plants and humans. This is a high-weightage chapter in CBSE board exams and demands a thorough understanding of both asexual and sexual reproduction methods.

Myclass24 offers detailed, step-by-step NCERT solutions that explain every question with clear language and supporting diagrams. Students preparing for their Class 10 board exams will find these solutions extremely helpful for understanding budding, fragmentation, regeneration, pollination, fertilisation, and the human reproductive system. These solutions are aligned with the latest NCERT textbook and CBSE marking scheme so you know exactly what to write in the exam.

Download NCERT Solutions for Class 10 Science Chapter 7 How Do Organisms Reproduce PDF

Get the free PDF of NCERT Solutions for Class 10 Science Chapter 7 from Myclass24. The PDF covers all NCERT exercise questions and in-text questions with accurate, exam-focused answers. It is formatted for easy reading on mobile phones and includes diagrams of reproductive structures. Download once and study anywhere, even without an internet connection.

Chapter 7: How Do Organisms Reproduce — Key Concepts, Facts & Topic Breakdown

This chapter is broadly divided into two parts: asexual reproduction and sexual reproduction. Asexual reproduction involves only one parent and produces offspring that are genetically identical to the parent (clones). Sexual reproduction involves two parents and the fusion of male and female gametes, leading to genetic variation in offspring.

Modes of Asexual Reproduction

Method	Organism	Description
Binary Fission	Amoeba, Bacteria	Parent divides into two equal daughter cells
Multiple Fission	Plasmodium	Parent divides into many daughter cells simultaneously
Budding	Yeast, Hydra	New organism grows as a bud from parent body
Fragmentation	Spirogyra	Body breaks into pieces, each grows into new organism
Regeneration	Planaria	Cut pieces regenerate into full organisms
Vegetative Propagation	Potato, Rose	New plant from root, stem, or leaf of parent
Spore Formation	Rhizopus (Bread mould)	Spores released from sporangia germinate into new organisms

Human Reproductive System — Key Points

Male reproductive organs: Testes, vas deferens, seminal vesicles, prostate gland, urethra, penis
Testes are located outside the abdominal cavity in scrotum to maintain temperature 2–3°C lower than body temperature — essential for sperm production
Female reproductive organs: Ovaries, fallopian tubes (oviduct), uterus, vagina
Fertilisation occurs in the fallopian tube — the zygote then implants in the uterus
Menstrual cycle is approximately 28 days; menstruation occurs when the egg is not fertilised
STDs (Sexually Transmitted Diseases) include AIDS (HIV), syphilis, gonorrhoea — condoms offer protection

Sexual Reproduction in Flowering Plants

Term	Meaning
Pollination	Transfer of pollen from anther to stigma
Self-Pollination	Pollen transferred within the same flower or same plant
Cross-Pollination	Pollen transferred from one plant to another
Fertilisation	Fusion of male gamete (pollen) with female gamete (ovum)
Germination	Development of seed into a new plant
Fruit	Mature ovary after fertilisation

Important Facts — Chapter 7

DNA copying during reproduction is not always perfect — mutations lead to variations
Variations are the raw material for evolution
In Hydra, both budding and regeneration can occur
Contraception methods include barrier methods (condom, diaphragm), chemical methods (pills), surgical methods (vasectomy, tubectomy), and IUDs
Placenta connects the developing foetus to the uterus and provides nutrition and oxygen