Class 10 Science Chapter 8 How Do Organisms Reproduce
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In this chapter, you will learn about asexual reproduction, sexual reproduction, reproductive organs in plants and humans, fertilization, reproduction in flowering plants, and reproductive health. The chapter also explains different methods of reproduction, including binary fission, budding, fragmentation, spore formation, and vegetative propagation. These concepts are essential for understanding the life cycle and survival of different organisms.
The study material is prepared in simple, clear, and student-friendly English, making it easy for every student to understand important biological concepts. Each topic is explained in a well-organized manner to help you learn faster and revise more effectively before examinations.
Whether you are preparing for class tests, annual examinations, or the HSLC Board Examination, this chapter will help you build a strong foundation in Biology, improve your conceptual understanding, and score higher marks in Science.
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- 📘 Easy & Simple Chapter Notes
- ❓ Complete Textbook Question Answers
- ⭐ Important Exam-Oriented Questions
- 📝 Quick Revision Notes
- 🎯 HSLC Board Exam Preparation
- 💡 Simple Explanations for Better Understanding
Start studying Class 10 Science Chapter 8 How Do Organisms Reproduce? Today and make your Biology preparation easier, smarter, and more effective.
Class 10 Science Chapter 8 How Do Organisms Reproduce
Selected Questions &Answers
Q: What methods are used to prevent pregnancy? HSLC ’15
Ans: The methods used to prevent pregnancy are condoms, oral contraceptives, Copper-T, etc.
Q: What is the function of the hormone adrenaline?
Ans: When a person becomes angry, excited, or frightened, this hormone helps in maintaining balance in the body.
Q: What is the function of the testes in humans?
Ans: To produce sperms and to secrete the male hormone called testosterone.
Q: Write the names of two methods of contraception.
Ans: Barrier method and surgical method.
Q: In which part of the human body does fertilization of the ovum take place?
Ans: In the oviduct or Fallopian tube.
Q: Write the name of the part of the seed that stores food.
Ans: Cotyledon.
Q: Write the names of two diseases caused by viruses.
Ans: AIDS and warts.
Q: What is the function of placental villi?
Ans: They help in providing a large surface area for the transfer of glucose and oxygen from the mother’s blood to the embryo.
Q: Choose the correct answer:
(i) The onset of reproductive maturity in human females is indicated by:
(a) Growth of body
(b) Change in hair texture
(c) Change in voice
(d) Menstruation
Ans: (d) Menstruation
(ii) Which of the following is not a female reproductive organ in humans?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube
Ans: (c) Vas deferens
Q: What is the advantage of tissue culture?
Ans: Tissue culture helps in producing many disease-free plants from a single parent plant.
Q: Write the names of two sexually transmitted diseases caused by bacteria.
Ans: Gonorrhoea and syphilis.
Q: What is the function of the hormone adrenaline?
Ans: When a person becomes angry, excited, or frightened, adrenaline helps in maintaining balance in the body.
Q: What is pollination?
Ans: The process of transfer of pollen grains from the anther of one flower to the stigma of another flower of a flowering plant is called pollination.
Q: What is cross-pollination?
Ans: Cross-pollination is the process in which pollen grains are transferred from the anther (male part) of a flower on one plant to the stigma(female part) of a flower on a different plant of the same species.
Q: In which type of reproduction does exchange of genetic material occur?
Ans: In sexual reproduction.
Q: Which hormone helps in the development of secondary sexual characters in males?
Ans: Testosterone hormone.
Q: What is the difference between fertilization and pollination? HSLC’20
Ans: The differences between pollination and fertilization are:
(a) Pollination occurs on the surface of the stigma, whereas fertilization occurs in the ovary.
(b) In pollination, fusion of cells does not occur, whereas in fertilization, fusion of cells occurs.
(c) Pollination occurs before fertilization, whereas fertilization occurs after the formation of gametes.
Q: What is the role of testes and prostate gland?
Ans: They help in the movement of sperms and provide nourishment to them.
Q: What changes are seen in the body of girls during adolescence?Ans: The changes are:
(a) Increase in the size of breasts.
(b) Beginning of menstrual cycle.
(c) Growth of hair in armpits and around reproductive organs.
(d) Skin becomes oily and pimples appear.
Q: If a woman uses Copper-T, does it prevent transmission of sexually transmitted diseases?
Ans: No, Copper-T does not prevent sexually transmitted diseases.
Q: Budding in a sexual reproduction occurs in—
(a) Amoeba
(b) Yeast
(c) Plasmodium
(d) Leishmania
Ans: (b) Yeast
Q: What is found in the anther?
(a) Sepal
(b) Ovule
(c) Pistil
(d) Pollen grains
Ans: (d) Pollen grains
Q: What are the advantages of sexual reproduction over asexual reproduction? HSLC ’18
Ans:
(a) In asexual reproduction, there is little variation among offspring, whereas in sexual reproduction ensures variation.
(b) Offspring produced by asexual reproduction have less chance of survival, whereas those produced by sexual reproduction have a higher chance of survival.
Q: What are the functions of human testes?
Ans: The testes produce sperms and secrete the male hormone testosterone.
Q: How does menstruation occur? HSLC ’20
Ans: The ovary produces one ovum every month. If the ovum is not fertilized, it breaks down and is discharged through the vagina in the form of blood and mucus. This process is called menstruation. This cycle continues every month for about 3 to 5 days.
Q: What is the need for DNA copying in reproduction?
Ans:
(a) It carries hereditary characteristics from parents to offspring.
(b) It produces offspring similar to parents.
(c) It also introduces some variations in the next generation.
Q: What are the differences between binary fission and multiple fission?
Ans:
(a) In binary fission, one organism divides into two new organisms, whereas in multiple fission, one organism produces many organisms at the same time.
(b) Amoeba reproduces by binary fission, whereas Plasmodium reproduces by multiple fission.
Q: Why cannot complex organisms reproduce by regeneration? Explain.
Ans: Organisms with complex body structures cannot reproduce through regeneration because their bodies are made of specialized cells organized into tissues and organs. Only simple organisms with less specialization can regenerate whole organisms from body parts.
Q: Draw a longitudinal section of a flower and label its different parts. HSLC ’15
Ans:
Q: What are the different methods of contraception? HSLC ’15Ans: The methods of contraception are—(a) Barrier method,
(b) Chemical method,
(c) Surgical method
Q: How does the process of reproduction help in maintaining the stability of the population of a species?
Ans: The process of reproduction helps in maintaining the stability of a species by maintaining a balance between birth rate and death rate, preventing extinction of the species, and introducing variations in the population.
Q: What is the reason for adopting contraceptive methods?
Ans: The adoption of contraceptive methods is mainly for controlling reproduction and protecting health.
Key reasons are as follows:
(a) Helps individuals or couples avoid pregnancies they are not ready for.
(b) Allows spacing between children and deciding the number of children.
(c) Reduces health risks for women by avoiding frequent or high-risk pregnancies.
(d) Some methods (like condoms) help protect against diseases such as HIV.
(e) Helps families manage resources, education, and overall quality of life
Q: In which part of the human body does fertilization of the ovum occur?
Ans: In the oviduct or Fallopian tube.
Q: Write the name of the part of the seed that stores food.
Ans: Cotyledon.
Q: Write the names of two female reproductive hormones and two male reproductive hormones.
Ans: Female reproductive hormones: (i) Estrogen and (ii) Progesterone. Male reproductive hormones: (i) Testosterone and (ii) Androgen (general group of male hormones)
These hormones regulate reproductive functions and development in males and females.
Q: Write the names of two diseases caused by viruses.
Ans: AIDS and warts.
Q: What is the function of placental villi?
Ans: Placental villi help in providing a large surface area for the transfer of glucose and oxygen from the mother’s blood to the embryo.
Q: What is the advantage of tissue culture?
Ans: Tissue culture helps in producing many disease-free plants from a single parent plant.
Q: Write the names of two sexually transmitted diseases caused by bacteria.
Ans: Gonorrhoea and syphilis.
Q: What is the function of the placenta?
Ans: The functions of the placenta are—
(a) It provides a large surface area for absorption.
(b) It transfers nutrients from the mother’s blood to the embryo.
(c) It removes waste materials produced by the embryo into the mother’sblood.
Q: What is pollination? HSLC ’20
Ans: In flowering plants, the process of transfer of pollen grains from the anther of one flower to the stigma of another flower is called pollination.
Q: Describe the process of sexual reproduction in flowering plants. HSLC ’19
Ans: The stamen is the male reproductive organ of a plant. Pollen grains are produced in it. The pistil is the female reproductive organ located at the center of the flower. It has three parts—ovary, style, and stigma. Ovules are present in the ovary. When pollen grains from the stamen are transferred to the stigma of the pistil, the process is called pollination. Due to various factors, the male gamete present in the pollen grain fuses with the female gamete present in the ovule. This process is called fertilization. The cell formed after the fusion of two gametes is called a zygote. The zygote develops into a seed. In this way, sexual reproduction in flowering plants is completed.
Q: By which process does reproduction occur in Amoeba? What are the advantages of sexual reproduction over asexual reproduction? HSLC’18
Ans: In Amoeba, reproduction occurs by asexual reproduction (binary fission). The advantages of sexual reproduction over asexual reproduction are: (a) In sexual reproduction, exchange of genetic material takes place, which may lead to the formation of new species.
(b) Sexual reproduction is one of the important factors of evolution.
Q: In which type of reproduction does exchange of genetic material occur? HSLC ’18
Ans: Exchange of genetic material occurs in sexual reproduction.
Q: Describe the budding process in Hydra. HSLC ’16
Ans: Budding in Hydra is a type of asexual reproduction. In this process, a bud develops from a part of the parent body due to repeated cell division.
The bud gradually grows and develops, and at a certain stage, it separates from the parent body and eventually forms a new individual.
Q: Draw a diagram of the female reproductive system of humans. HSLC’17
Ans: A labeled diagram of the human female reproductive system should include ovaries, fallopian tubes (oviducts), uterus, cervix, and vagina.
Q: Describe the method of division in unicellular organisms. HSLC’17
Ans: Unicellular organisms reproduce by cell division or binary fission.
Many unicellular organisms like bacteria and protozoa complete this process by dividing the cell equally into two daughter cells.
Q: Write the technique of tissue culture used by plant breeders. HSLC’17
Ans: In tissue culture, plant breeders first take a small piece of growing tissue (meristem) from a plant and place it in an artificial medium. In this medium, rapid cell division occurs and a mass of cells called ‘callus’ is formed.
This callus is then transferred to another medium containing nutrients and growth substances, where it develops into a complete plant.
Q: What is cross-pollination? HSLC ’18
Ans: Cross-pollination is the process in which pollen grains are transferred from the anther of one flower to the stigma of another flower of the same species.
Q: Describe the different methods of contraception. HSLC ’15
Ans: There are different methods of contraception, such as:
(a) Surgical method: It is mainly of two types—vasectomy and tubectomy. In vasectomy, the vas deferens in males is cut and tied. In tubectomy, a part of the fallopian tube in females is cut and tied.
(b) Barrier method: In this method, sperms are prevented from entering the female reproductive system. Condoms are commonly used.
(c) Chemical method: In this method, women use chemical substances such as tablets, jellies, pastes, etc. to prevent pregnancy.
(d) Intrauterine contraceptive method: In this method, Copper-T is placed in the uterus to prevent pregnancy.
Q: Which hormone helps in the development of secondary sexual characters in males?
Ans: Testosterone hormone.
Q: What is called the ‘blueprint’ of life?
Ans: DNA.
Q: Through which processes does HIV infection spread?
Ans: HIV infection spreads through the following processes:
(a) From mother: An infected mother can transmit HIV to her child during pregnancy or childbirth.
(b) Unprotected sexual contact: About 70–80% of HIV infections occur due to unprotected sexual activities.
(c) Through blood: If a person receives blood from an HIV-infected person, the virus can be transmitted.
Q: What is the full form of DNA? Where is it found in the cell? What is its role in reproduction?
Ans: The full form of DNA is Deoxyribonucleic Acid. It is found in the nucleus of the cell. During reproduction, DNA carries hereditary traits from parents to offspring through reproductive cells.
Q: How does the embryo obtain nutrition in the mother’s body?
Ans: The embryo grows and develops in the uterus of the mother. It remains attached to the inner lining of the uterus through a special tissue called the placenta. Through the placenta, the embryo receives nutrition from the mother’s blood.
Multiple Choice Questions (MCQ)
Q: Transfer of pollen from stamen to the stigma of the same flower is called—
(a) Photosynthesis
(b) Self-pollination
(c) Cross-pollination
(d) None of the above
Ans: (b) Self-pollination
Q: What is found in the anther?
(a) Sepal
(b) Ovule
(c) Pistil
(d) Pollen grains
Ans: (d) Pollen grains
Q: The fusion of sperm and ovum is called—
(a) Division
(b) Budding
(c) Fragmentation
(d) Fertilization
Ans: (d) Fertilization
Q: In which organism is budding observed?
(a) Hydra
(b) Snail
(c) Earthworm
(d) Leech
Ans: (a) Hydra
Q: The process of binary fission in Amoeba is—
(a) Binary fission or division
(b) Fragmentation
(c) Vegetative propagation
(d) Regeneration
Ans: (a) Binary fission or division
Q: Which organism reproduces by regeneration?
(a) Leishmania
(b) Amoeba
(c) Planaria
(d) Plasmodium
Ans: (c) Planaria
Q: Budding in asexual reproduction occurs in—
(a) Yeast
(b) Plasmodium
(c) Leishmania
(d) Amoeba
Ans: (a) Yeast
Q: The fungus that grows on bread is—
(a) Thallophyta
(b) Bryophyta
(c) Rhizopus
(d) None of these
Ans: (c) Rhizopus
Q: Which of the following is a male reproductive organ in humans?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube
Ans: (c) Vas deferens
Q: The hormone responsible for milk secretion is—
(a) Prolactin
(b) Testosterone
(c) Estrogen
(d) Relaxin
Ans: (a) Prolactin
Q: A female sex hormone is—
(a) Estrogen
(b) Testosterone
(c) Gibberellin
(d) Pituitary
Ans: (a) Estrogen
Q: The hormone secreted by the testes is—
(a) Estrogen
(b) Testosterone
(c) Auxin
(d) Relaxin
Ans: (b) Testosterone
