THE BUSY BRAINS • BY MANSI SARASWAT
HOW DO ORGANISMS REPRODUCE?
Class 10 Science | Important Questions with Answers
Pre-Board & Board Exam Preparation
| NCERT-Based Questions | Biology | Diagrams | MCQs | Case-Based Questions
Class 10 Science – How do Organisms Reproduce? is an important Biology chapter for CBSE and Board Exam preparation. The chapter explains why organisms reproduce, how DNA copying takes place, why variations arise and how organisms reproduce through different asexual and sexual reproduction methods.
This comprehensive Class 10 How do Organisms Reproduce Important Questions with Answers resource covers binary fission, multiple fission, budding, fragmentation, regeneration, vegetative propagation, spore formation, sexual reproduction, pollination, fertilisation, human reproductive systems, puberty, menstruation, reproductive health and contraception.
Students preparing for CBSE Pre-Board and Board Exams should pay special attention to the differences between asexual and sexual reproduction, advantages of sexual reproduction, reproduction in flowering plants, male and female reproductive systems, fertilisation, menstruation and contraceptive methods.
The post also includes important diagram-based questions. Practise drawing and labelling the longitudinal section of a flower, male reproductive system, female reproductive system, budding in Hydra, binary fission, regeneration, spore formation and germination.
MUST DO
Asexual Reproduction, Sexual Reproduction, Pollination, Fertilisation & Human Reproduction
VERY IMPORTANT
DNA Copying, Variation, Reproductive Systems, Puberty, Menstruation & Placenta
PRACTICE
Diagrams, MCQs, Case-Based Questions, NCERT Questions & Exercise
⭐ Board Exam Focus:
Learn the definitions, differences, processes and
labelled diagrams. For long-answer questions,
write answers in logical steps and use correct biological
terminology.
1. DNA Copying and Variation
MUST DO
Q1. Why do organisms reproduce?
Answer:
Reproduction enables organisms to create new individuals of their
species.
It is not necessary for the survival of an individual organism,
but it is important for the continuation and maintenance of
populations of species.
Q2. What is the basic event in reproduction?
A basic event in reproduction is the
creation of a copy of DNA.
DNA contains information involved in inheritance and in making
proteins that contribute to the organism's body design.
VERY IMPORTANT
Q3. Why is DNA copying important in reproduction?
DNA copying is important because the new individual needs a copy of
the genetic information of the parent.
During reproduction, DNA is copied and the copies are distributed
into the new cells along with the necessary cellular apparatus.
Q4. Why are the copies of DNA not always absolutely identical?
Biochemical reactions involved in DNA copying are not absolutely
reliable.
Therefore, small variations can occur during copying.
The resulting DNA copies may be similar to the original but not
completely identical.
Q5. What is variation?
Variation refers to differences that arise among individuals of
a species.
During reproduction, variations can arise because DNA copying
is not perfectly accurate.
VERY IMPORTANT
Q6. Why is variation beneficial to a species but not necessarily to an individual?
A particular variation may not provide an advantage to every
individual.
However, if environmental conditions change, some variations may
help certain individuals survive.
For example, heat-resistant bacteria may survive better when
temperatures increase.
Thus, variation can increase the chances of survival of a species
over time.
Q7. How is reproduction linked to the stability of populations?
Reproduction maintains the population of a species by producing
new individuals.
Accurate DNA copying helps maintain the body design of organisms
suited to a particular niche, while variations provide possibilities
for survival when environmental conditions change.
2. Asexual Reproduction
MUST DO
Q8. What is asexual reproduction?
Asexual reproduction is a mode of reproduction in which a new
generation is created from a single individual.
Examples include fission, budding, fragmentation, regeneration,
vegetative propagation and spore formation.
Q9. Name the different modes of asexual reproduction discussed in the chapter.
The major modes discussed are:
- Fission
- Fragmentation
- Regeneration
- Budding
- Vegetative propagation
- Spore formation
Q10. Why are simple modes of reproduction possible in some organisms but not in complex multicellular organisms?
Simple organisms may have a relatively simple body organisation.
In complex multicellular organisms, specialised cells form tissues
and organs that have specific positions and functions.
Therefore, simply dividing the body cell-by-cell would not be
practical.
3. Fission – Binary and Multiple Fission
MUST DO
Q11. What is fission?
Fission is a mode of asexual reproduction in which a unicellular
organism divides to produce new individuals.
Many bacteria and protozoa reproduce through fission.
Q12. What is binary fission?
Binary fission is a type of fission in which one parent cell divides
to form two daughter cells.
For example, Amoeba can reproduce by binary fission.
Q13. How does binary fission in Amoeba differ from that in Leishmania?
In Amoeba, the cell can divide in
any plane.
Leishmania has a whip-like structure at one end and therefore
binary fission occurs in a
definite orientation in relation to that structure.
VERY IMPORTANT
Q14. What is multiple fission?
Multiple fission is a type of fission in which a single organism
divides to produce many daughter cells simultaneously.
The chapter gives Plasmodium as an example.
Q15. Differentiate between binary fission and multiple fission.
| Binary Fission | Multiple Fission |
|---|---|
| One parent cell divides into two daughter cells. | One parent organism produces many daughter cells simultaneously. |
| Example: Amoeba. | Example: Plasmodium. |
4. Fragmentation, Regeneration and Budding
Q16. What is fragmentation?
Fragmentation is a mode of asexual reproduction in which an organism
breaks into smaller pieces or fragments and these fragments grow
into new individuals.
Spirogyra is an example.
MUST DO
Q17. What is regeneration?
Regeneration is the ability of an organism to give rise to new
individuals from its body parts.
The chapter gives examples of
Hydra and Planaria.
In these organisms, specialised cells proliferate and form different
cell types and tissues.
Q18. Why is regeneration not the same as reproduction?
Although organisms such as Hydra and Planaria can form new individuals
from body parts, most organisms do not normally depend on being cut
into pieces for reproduction.
Therefore, regeneration should not be treated as the normal
reproductive process of all organisms.
VERY IMPORTANT
Q19. What is budding?
Budding is a mode of asexual reproduction in which a small
outgrowth called a bud develops on the parent body.
The bud grows due to repeated cell division, develops into a tiny
individual and eventually detaches from the parent.
Hydra reproduces by budding.
Q20. How does budding occur in Hydra?
In Hydra, a bud develops as an outgrowth at a specific site on
the parent body.
Repeated cell division causes the bud to grow.
When it becomes mature, it detaches from the parent and becomes
an independent individual.
5. Vegetative Propagation and Spore Formation
MUST DO
Q21. What is vegetative propagation?
Vegetative propagation is a mode of reproduction in plants in which
parts such as the root, stem or leaves develop into
new plants under suitable conditions.
Q22. Give examples of plants that can be propagated vegetatively.
Examples discussed in the chapter include:
sugarcane, roses, grapes, banana, orange and jasmine.
Q23. What are the advantages of vegetative propagation?
Advantages include:
- Plants can be produced from vegetative parts.
- Plants may bear flowers and fruits earlier than plants grown from seeds.
- Plants that have lost the ability to produce seeds can still be propagated.
- The plants produced are genetically similar enough to the parent to retain its characteristics.
Q24. What is spore formation?
Spore formation is a mode of asexual reproduction in which
special reproductive structures contain spores.
In bread mould Rhizopus, the structures called
sporangia contain spores.
The spores have thick protective walls and can develop into new
individuals when suitable conditions are available.
VERY IMPORTANT
Q25. How does spore formation help an organism reproduce?
The spores are produced in large numbers and are protected by
thick walls.
When they come into contact with a suitable moist surface,
they can begin to grow into new individuals.
6. Sexual Reproduction
MUST DO
Q26. What is sexual reproduction?
Sexual reproduction is a mode of reproduction that involves
the participation of two individuals in the
creation of a new individual.
It involves the combination of genetic material from two individuals.
Q27. What is the major advantage of sexual reproduction over asexual reproduction?
Sexual reproduction combines DNA from two different individuals.
This produces new combinations of variations and therefore
generates greater variation in the population.
Such variation can be useful for the survival of species when
environmental conditions change.
Q28. Why does sexual reproduction not result in doubling of DNA in every generation?
Specialised germ cells contain only half the number of chromosomes
and half the amount of DNA compared with normal body cells.
This reduction occurs through a type of cell division called
meiosis.
When male and female germ cells combine, the chromosome number and
DNA content are restored in the new individual.
Q29. What are male and female gametes?
The germ cell that is conventionally called the
male gamete is generally smaller and motile.
The female gamete is generally larger and contains
stored food.
7. Sexual Reproduction in Flowering Plants
MUST DO
Q30. Which parts of a flower are the reproductive parts?
The reproductive parts of a flower are:
- Stamen – male reproductive part
- Pistil – female reproductive part
Q31. What is a unisexual flower?
A flower that contains either stamens or pistil is called a
unisexual flower.
Examples mentioned in the chapter include
papaya and watermelon.
Q32. What is a bisexual flower?
A flower that contains both stamens and pistil is called a
bisexual flower.
Examples include Hibiscus and mustard.
VERY IMPORTANT
Q33. What are the three parts of the pistil?
The pistil has three main parts:
- Stigma
- Style
- Ovary
Q34. What is pollination?
Pollination is the transfer of pollen grains from the
anther to the stigma.
Q35. Differentiate between self-pollination and cross-pollination.
| Self-Pollination | Cross-Pollination |
|---|---|
| Pollen is transferred within the same flower. | Pollen is transferred from one flower to another. |
| Occurs in the same flower. | May involve different flowers of the same species. |
| Does not require transfer between two flowers. | Transfer can occur through wind, water or animals. |
MUST DO
Q36. What is fertilisation?
Fertilisation is the fusion of the male germ cell with the female
gamete.
It results in the formation of a
zygote.
The zygote can develop into a new plant.
Q37. What happens after fertilisation in a flowering plant?
After fertilisation:
- The zygote divides to form an embryo.
- The ovule develops into a seed.
- The ovary develops into a fruit.
- The embryo inside the seed can develop into a seedling under suitable conditions.
Q38. What is germination?
Germination is the process in which the embryo present inside a seed
develops into a seedling under suitable conditions.
8. Reproduction in Human Beings
Q39. What type of reproduction occurs in human beings?
Human beings reproduce through
sexual reproduction.
The process involves male and female reproductive systems and
the fusion of male and female germ cells.
VERY IMPORTANT
Q40. What is puberty?
Puberty is the period during adolescence when the reproductive
tissues begin to mature and the body undergoes changes associated
with sexual maturation.
These changes occur gradually over months and years and do not
necessarily happen at exactly the same age in every person.
Q41. What changes are commonly observed during puberty?
Changes can include:
- Growth of hair in the armpits and genital region.
- Changes in skin and development of pimples.
- Changes in body proportions.
- Increase in breast size in girls.
- Menstruation begins in girls.
- Facial hair develops in boys.
- Voice changes occur in boys.
9. Male Reproductive System
MUST DO
Q42. Name the main parts of the male reproductive system in humans.
The male reproductive system includes:
- Testes
- Scrotum
- Vas deferens
- Seminal vesicles
- Prostate gland
- Urethra
- Penis
Q43. What are the functions of the testes?
The testes:
- Produce sperm or male germ cells.
- Secrete testosterone.
VERY IMPORTANT
Q44. Why are the testes located outside the abdominal cavity?
The testes are located in the scrotum outside the abdominal cavity
because sperm formation requires a temperature lower than the
normal body temperature.
Q45. What is the function of the vas deferens?
The vas deferens transports sperm from the testes towards the
urethra and ultimately towards the site where fertilisation may occur.
Q46. What are the functions of seminal vesicles and prostate gland?
The secretions of glands such as the seminal vesicles and prostate
gland mix with sperm.
The resulting fluid makes transport of sperm easier and also
provides nutrition.
10. Female Reproductive System
MUST DO
Q47. Name the main parts of the female reproductive system.
The female reproductive system includes:
- Ovaries
- Fallopian tubes / oviducts
- Uterus
- Cervix
- Vagina
Q48. What is the function of the ovaries?
The ovaries produce female germ cells or eggs.
They are also involved in the production of hormones.
Q49. What is the role of the fallopian tube?
The egg travels from the ovary towards the uterus through the
fallopian tube.
Fertilisation occurs in the fallopian tube.
VERY IMPORTANT
Q50. What happens to the fertilised egg after fertilisation?
The fertilised egg or zygote begins dividing and forms an embryo.
The embryo becomes implanted in the lining of the uterus, where
it continues to grow and develop.
Q51. What is the role of the placenta?
The placenta is a special tissue embedded in the uterine wall.
It provides a large surface area through which substances such as
glucose and oxygen can pass from the mother's blood
to the embryo.
Waste substances from the developing embryo can also pass into the
mother's blood through the placenta.
11. Menstruation and Reproductive Health
MUST DO
Q52. What happens when the egg is not fertilised?
If the egg is not fertilised, it survives for about one day.
The uterus had prepared a thick and spongy lining to receive a
fertilised egg.
When fertilisation does not occur, this lining is no longer needed
and breaks down and comes out through the vagina as blood and mucus.
This process is called menstruation.
Q53. What is menstruation?
Menstruation is the monthly process in which the thickened lining
of the uterus breaks down and is discharged through the vagina as
blood and mucus when fertilisation has not occurred.
The chapter states that it usually lasts for about
two to eight days.
Q54. What are sexually transmitted diseases?
Sexually transmitted diseases are infections that can be transmitted
from one person to another through sexual contact.
The chapter mentions bacterial infections such as
gonorrhoea and syphilis and viral infections such as
warts and HIV-AIDS.
VERY IMPORTANT
Q55. How can condoms help in reproductive health?
Condoms act as a mechanical barrier.
They can help prevent sperm from reaching the egg and also help
reduce transmission of many sexually transmitted infections.
Q56. What are the different methods of contraception discussed in the chapter?
The chapter discusses several categories:
- Mechanical barriers such as condoms.
- Oral contraceptive pills.
- Intrauterine devices such as Copper-T.
- Surgical methods involving blocking the vas deferens or fallopian tubes.
Q57. Will a Copper-T protect a woman from sexually transmitted diseases?
No.
Copper-T is a contraceptive device used to help prevent pregnancy.
It does not provide protection against sexually transmitted diseases.
Q58. Why are contraceptive methods used?
Contraceptive methods may be used to:
- Prevent unwanted pregnancy.
- Plan the timing and number of children.
- Allow individuals to make informed reproductive choices.
12. Draw & Label – Important Diagram Questions
⭐ Diagram Practice is Important:
The NCERT exercise directly asks students to
draw a labelled diagram of the longitudinal section
of a flower. The chapter also contains several
important reproductive diagrams. Practise them neatly with
correct labels.
DIAGRAM – 1
Q59. Draw a neat and labelled diagram of the longitudinal section of a flower.
Students should label:
Sepal • Petal • Anther • Filament • Stigma •
Style • Ovary • Ovule
⭐ Board Tip: Draw the flower in longitudinal section and keep label lines straight and clear.
DIAGRAM – 2
Q60. Draw and label the human male reproductive system.
Important labels:
Urinary bladder • Seminal vesicle •
Prostate gland • Vas deferens •
Urethra • Penis • Testis • Scrotum
⭐ Focus on the location and correct labelling of testes, vas deferens and accessory glands.
DIAGRAM – 3
Q61. Draw and label the human female reproductive system.
Important labels:
Ovary • Oviduct / Fallopian tube •
Uterus • Cervix • Vagina
⭐ Board Tip: Draw both ovaries and show the fallopian tubes clearly.
DIAGRAM – 4
Q62. Draw the stages of budding in Hydra and label the bud.
Show:
Parent Hydra → Developing Bud → Mature Bud → New Individual
DIAGRAM – 5
Q63. Draw the stages of binary fission in Amoeba.
Show the sequence:
Parent Amoeba → Nuclear division →
Cytoplasmic division → Two daughter cells
DIAGRAM – 6
Q64. Draw the stages of binary fission in Leishmania.
Important point:
Show division in a definite orientation in relation to the whip-like structure.
DIAGRAM – 7
Q65. Draw and label multiple fission in Plasmodium.
Show:
Parent cell → Multiple daughter cells
DIAGRAM – 8
Q66. Draw regeneration in Planaria.
Show:
Planaria → Body pieces → Regenerated individuals
DIAGRAM – 9
Q67. Draw and label spore formation in Rhizopus.
Important labels:
Sporangium • Spores • Sporangiophore
DIAGRAM – 10
Q68. Draw the germination of a seed and label the main parts.
Important labels:
Cotyledon • Plumule • Radicle
DIAGRAM – 11
Q69. Draw pollen germination on the stigma.
Show:
Pollen grain • Pollen tube • Stigma •
Style • Ovary • Female germ-cell
🎯 Diagram Revision Checklist
- ☑ Longitudinal section of a flower
- ☑ Male reproductive system
- ☑ Female reproductive system
- ☑ Binary fission in Amoeba
- ☑ Binary fission in Leishmania
- ☑ Multiple fission in Plasmodium
- ☑ Regeneration in Planaria
- ☑ Budding in Hydra
- ☑ Vegetative propagation examples
- ☑ Spore formation in Rhizopus
- ☑ Germination of seed
- ☑ Germination of pollen on stigma
13. NCERT-Based Board Questions
Q70. How is the process of pollination different from fertilisation?
Pollination is the transfer of pollen grains from
the anther to the stigma.
Fertilisation is the fusion of the male germ cell with the female gamete to form a zygote.
Fertilisation is the fusion of the male germ cell with the female gamete to form a zygote.
Q71. What is the role of seminal vesicles and the prostate gland?
Their secretions mix with sperm to form a fluid that makes sperm
transport easier and provides nutrition.
Q72. What changes are seen in girls at the time of puberty?
Changes include:
- Increase in breast size.
- Darkening of the skin of the nipples.
- Beginning of menstruation.
- Growth of hair in the armpits and genital region.
- Other changes associated with sexual maturation.
Q73. How does the embryo get nourishment inside the mother's body?
The embryo receives nourishment from the mother's blood through
the placenta.
The placenta provides a large surface area for the transfer of
glucose and oxygen to the embryo.
Waste substances from the embryo can also pass into the mother's
blood through the placenta.
PRACTICE
Q74. If a woman is using a Copper-T, will it help protect her from sexually transmitted diseases?
No.
Copper-T is a contraceptive device used to prevent pregnancy.
It does not protect against sexually transmitted diseases.
NCERT EXERCISE
Q75. In which organism does asexual reproduction take place through budding?
Answer: Yeast.
Q76. Which of the following is not a part of the female reproductive system in human beings?
Answer: Vas deferens.
The vas deferens is a part of the male reproductive system.
Q77. What does the anther contain?
Answer: Pollen grains.
MUST DO – 5 MARKS
Q78. What are the advantages of sexual reproduction over asexual reproduction?
The major advantage of sexual reproduction is that it combines
genetic material from two different individuals.
This creates new combinations of variations.
Greater variation increases the possibility that some individuals
will survive if environmental conditions change.
Thus, sexual reproduction can contribute to the survival of species
over time.
Q79. What are the functions performed by the testes in human beings?
The testes:
- Produce sperm.
- Secrete testosterone.
Q80. Why does menstruation occur?
Every month the uterus prepares a thick and spongy lining to
receive a fertilised egg.
If the egg is not fertilised, the lining is no longer required.
It breaks down and is discharged through the vagina as blood
and mucus.
This process is called menstruation.
NCERT DIAGRAM QUESTION
Q81. Draw a labelled diagram of the longitudinal section of a flower.
Important labels:
Sepal, petal, anther, filament, stigma, style, ovary and ovule.
Q82. What are the different methods of contraception?
Methods discussed in the chapter include:
- Mechanical barriers such as condoms.
- Oral contraceptive pills.
- Intrauterine devices such as Copper-T.
- Surgical methods involving the vas deferens or fallopian tubes.
Q83. How are modes of reproduction different in unicellular and multicellular organisms?
In unicellular organisms, reproduction can occur through relatively
simple processes such as fission.
Multicellular organisms have specialised cells, tissues and organs,
so their reproduction generally involves more specialised and
complex mechanisms.
Q84. How does reproduction help provide stability to populations of species?
Reproduction produces new individuals and helps maintain the
population of a species.
DNA copying helps maintain the basic body design of the species,
while variations provide possibilities for survival when the
environment changes.
Q85. What could be the reasons for adopting contraceptive methods?
Contraceptive methods may be adopted to:
- Prevent unwanted pregnancy.
- Plan the timing and number of children.
- Make informed reproductive choices.
- Protect reproductive health where appropriate methods are used.
14. Important MCQs – How do Organisms Reproduce?
Q86. Asexual reproduction through budding occurs in:
(a) Amoeba
(b) Yeast
(c) Plasmodium
(d) Leishmania
(a) Amoeba
(b) Yeast
(c) Plasmodium
(d) Leishmania
✔ Answer: (b) Yeast
Q87. Binary fission in Amoeba can occur:
(a) Only vertically
(b) Only horizontally
(c) In any plane
(d) Only longitudinally
(a) Only vertically
(b) Only horizontally
(c) In any plane
(d) Only longitudinally
✔ Answer: (c) In any plane
Q88. Multiple fission occurs in:
(a) Hydra
(b) Plasmodium
(c) Rose
(d) Yeast
(a) Hydra
(b) Plasmodium
(c) Rose
(d) Yeast
✔ Answer: (b) Plasmodium
Q89. Vegetative propagation can occur through:
(a) Root
(b) Stem
(c) Leaf
(d) All of these
(a) Root
(b) Stem
(c) Leaf
(d) All of these
✔ Answer: (d) All of these
Q90. The reproductive structure of Rhizopus containing spores is called:
(a) Ovary
(b) Sporangium
(c) Stigma
(d) Bud
(a) Ovary
(b) Sporangium
(c) Stigma
(d) Bud
✔ Answer: (b) Sporangium
Q91. The male reproductive part of a flower is:
(a) Pistil
(b) Stamen
(c) Ovary
(d) Stigma
(a) Pistil
(b) Stamen
(c) Ovary
(d) Stigma
✔ Answer: (b) Stamen
Q92. The female reproductive part of a flower is:
(a) Stamen
(b) Anther
(c) Pistil
(d) Filament
(a) Stamen
(b) Anther
(c) Pistil
(d) Filament
✔ Answer: (c) Pistil
Q93. Transfer of pollen grains from anther to stigma is called:
(a) Fertilisation
(b) Pollination
(c) Germination
(d) Regeneration
(a) Fertilisation
(b) Pollination
(c) Germination
(d) Regeneration
✔ Answer: (b) Pollination
Q94. Fusion of male and female germ cells produces:
(a) Spore
(b) Bud
(c) Zygote
(d) Pollen grain
(a) Spore
(b) Bud
(c) Zygote
(d) Pollen grain
✔ Answer: (c) Zygote
Q95. Fertilisation in human beings occurs in the:
(a) Uterus
(b) Ovary
(c) Fallopian tube
(d) Vagina
(a) Uterus
(b) Ovary
(c) Fallopian tube
(d) Vagina
✔ Answer: (c) Fallopian tube
Q96. Which organ produces sperm in human males?
(a) Prostate gland
(b) Testes
(c) Urethra
(d) Seminal vesicle
(a) Prostate gland
(b) Testes
(c) Urethra
(d) Seminal vesicle
✔ Answer: (b) Testes
Q97. The organ in which the embryo develops is:
(a) Ovary
(b) Uterus
(c) Fallopian tube
(d) Vagina
(a) Ovary
(b) Uterus
(c) Fallopian tube
(d) Vagina
✔ Answer: (b) Uterus
Q98. Which structure provides nourishment to the developing embryo?
(a) Placenta
(b) Cervix
(c) Ovary
(d) Urethra
(a) Placenta
(b) Cervix
(c) Ovary
(d) Urethra
✔ Answer: (a) Placenta
Q99. Which contraceptive device is placed inside the uterus?
(a) Copper-T
(b) Condom
(c) Oral pill
(d) None
(a) Copper-T
(b) Condom
(c) Oral pill
(d) None
✔ Answer: (a) Copper-T
Q100. Which process produces greater variation by combining DNA from two individuals?
(a) Sexual reproduction
(b) Binary fission
(c) Budding
(d) Fragmentation
(a) Sexual reproduction
(b) Binary fission
(c) Budding
(d) Fragmentation
✔ Answer: (a) Sexual reproduction
15. Case-Based Questions – Board Exam Practice
Case Study 1 – DNA Copying and Variation
During reproduction, DNA is copied. The copying process is not absolutely accurate, so small variations may arise. Some variations may be harmful, while others may help organisms survive changing environmental conditions.
Q1. Why is DNA copying necessary during reproduction?
Q2. Why are DNA copies not always identical?
Q3. Why can variation be useful to a species?
Answers:
1. It transfers genetic information to the new individual.
2. DNA-copying biochemical reactions are not perfectly reliable.
3. Some variations may help individuals survive environmental changes, increasing the survival chances of the species.
1. It transfers genetic information to the new individual.
2. DNA-copying biochemical reactions are not perfectly reliable.
3. Some variations may help individuals survive environmental changes, increasing the survival chances of the species.
Case Study 2 – Asexual Reproduction
Different organisms use different methods of asexual reproduction. Amoeba divides into two daughter cells, Plasmodium produces many daughter cells, Hydra forms buds and Rhizopus produces spores.
Q1. Name the process in Amoeba.
Q2. Name the process in Plasmodium.
Q3. Which organism reproduces through budding?
Q4. Where are spores present in Rhizopus?
Answers:
1. Binary fission.
2. Multiple fission.
3. Hydra.
4. Spores are contained in sporangia.
1. Binary fission.
2. Multiple fission.
3. Hydra.
4. Spores are contained in sporangia.
Case Study 3 – Flower Reproduction
A flower contains reproductive structures. The stamen produces pollen grains, while the pistil contains the ovary and ovules. Pollen must reach the stigma before the male germ cell can fuse with the female gamete.
Q1. What is the male reproductive part?
Q2. What is the female reproductive part?
Q3. What is pollination?
Q4. What is formed after fertilisation?
Answers:
1. Stamen.
2. Pistil.
3. Transfer of pollen from anther to stigma.
4. Zygote.
1. Stamen.
2. Pistil.
3. Transfer of pollen from anther to stigma.
4. Zygote.
Case Study 4 – Human Reproduction
In humans, the testes produce sperm and the ovaries produce eggs. The sperm travels through the male reproductive tract, while the egg travels through the fallopian tube. Fertilisation occurs in the fallopian tube and the embryo develops in the uterus.
Q1. Where are sperm produced?
Q2. Where are eggs produced?
Q3. Where does fertilisation occur?
Q4. Where does the embryo develop?
Answers:
1. Testes.
2. Ovaries.
3. Fallopian tube.
4. Uterus.
1. Testes.
2. Ovaries.
3. Fallopian tube.
4. Uterus.
Case Study 5 – Reproductive Health
Different contraceptive methods are available to prevent pregnancy. Some methods act as barriers, some alter hormonal balance and others are placed inside the uterus or involve surgical blocking of reproductive passages.
Q1. Give one mechanical barrier method.
Q2. Name one intrauterine contraceptive device.
Q3. Does Copper-T protect against sexually transmitted diseases?
Answers:
1. Condom.
2. Copper-T.
3. No.
1. Condom.
2. Copper-T.
3. No.
16. Quick Revision – How do Organisms Reproduce?
| Concept | Key Point |
|---|---|
| Reproduction | Produces new individuals and maintains populations. |
| DNA Copying | Basic event in reproduction. |
| Variation | Differences arising during reproduction. |
| Asexual Reproduction | New generation from a single individual. |
| Binary Fission | One cell divides into two daughter cells. |
| Multiple Fission | One organism produces many daughter cells. |
| Fragmentation | Fragments grow into new individuals. |
| Regeneration | Body pieces can form new individuals in certain organisms. |
| Budding | New individual develops as a bud. |
| Vegetative Propagation | New plants develop from roots, stems or leaves. |
| Spore Formation | Spores develop into new individuals under suitable conditions. |
| Pollination | Transfer of pollen from anther to stigma. |
| Fertilisation | Fusion of male and female germ cells. |
| Male Reproductive Organ | Testes produce sperm. |
| Female Reproductive Organ | Ovaries produce eggs. |
| Fertilisation in Humans | Occurs in the fallopian tube. |
| Embryo Development | Occurs in the uterus. |
| Placenta | Helps transfer nutrients and oxygen to the embryo. |
| Menstruation | Shedding of the uterine lining when fertilisation does not occur. |
| Copper-T | Intrauterine contraceptive device. |
⭐ One-Minute Revision:
DNA Copying → Variation → Reproduction
Asexual → One Parent
Sexual → Two Individuals
Stamen → Male Part
Pistil → Female Part
Anther → Pollen
Ovary → Ovules
Pollination → Anther to Stigma
Fertilisation → Fusion of Gametes
Testes → Sperm
Ovaries → Eggs
Fallopian Tube → Fertilisation
Uterus → Embryo Development
Placenta → Nourishment
DNA Copying → Variation → Reproduction
Asexual → One Parent
Sexual → Two Individuals
Stamen → Male Part
Pistil → Female Part
Anther → Pollen
Ovary → Ovules
Pollination → Anther to Stigma
Fertilisation → Fusion of Gametes
Testes → Sperm
Ovaries → Eggs
Fallopian Tube → Fertilisation
Uterus → Embryo Development
Placenta → Nourishment
17. Class 10 Board Exam Final Checklist
- ☑ Learn why organisms reproduce.
- ☑ Understand DNA copying.
- ☑ Learn the importance of variation.
- ☑ Differentiate asexual and sexual reproduction.
- ☑ Learn binary and multiple fission.
- ☑ Learn fragmentation, regeneration and budding.
- ☑ Learn vegetative propagation and its advantages.
- ☑ Learn spore formation in Rhizopus.
- ☑ Understand why sexual reproduction produces variation.
- ☑ Learn meiosis and germ cells.
- ☑ Learn the reproductive parts of a flower.
- ☑ Differentiate self-pollination and cross-pollination.
- ☑ Learn fertilisation and germination.
- ☑ Learn puberty and sexual maturation.
- ☑ Learn male reproductive system.
- ☑ Learn female reproductive system.
- ☑ Understand fertilisation and embryo development.
- ☑ Learn the role of placenta.
- ☑ Understand menstruation.
- ☑ Learn contraception methods.
- ☑ Remember that Copper-T does not protect against STDs.
- ☑ Practise all important diagrams.
- ☑ Practise NCERT exercise questions.
- ☑ Practise MCQs and case-based questions.
18. Exam Strategy for This Chapter
How to score better in “How do Organisms Reproduce?”
1. Learn diagrams with labels.
Do not only look at the diagram. Practise drawing it yourself.
2. Learn differences in table form.
Practise: Asexual vs Sexual reproduction
Binary vs Multiple fission
Self-pollination vs Cross-pollination
3. Learn the sequence of processes.
For example:
4. Use correct keywords.
Important terms include: DNA copying, variation, fission, budding, regeneration, vegetative propagation, spores, pollination, fertilisation, gametes, zygote, puberty, placenta, menstruation and contraception.
5. For 5-mark questions:
Write answers in points, include examples and draw a labelled diagram wherever appropriate.
Do not only look at the diagram. Practise drawing it yourself.
2. Learn differences in table form.
Practise: Asexual vs Sexual reproduction
Binary vs Multiple fission
Self-pollination vs Cross-pollination
3. Learn the sequence of processes.
For example:
Pollination
→
Pollen Tube
→
Fertilisation
→
Zygote
→
Embryo
Important terms include: DNA copying, variation, fission, budding, regeneration, vegetative propagation, spores, pollination, fertilisation, gametes, zygote, puberty, placenta, menstruation and contraception.
5. For 5-mark questions:
Write answers in points, include examples and draw a labelled diagram wherever appropriate.
🎯 Learn Biology. Practise Diagrams. Score Better.
Revise Class 10 Science – How do Organisms Reproduce? with NCERT-based important questions, answers, diagrams, MCQs, case-based questions and Board Exam revision.
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