Class 10th Science Chapter 7 – How Do Organisms Reproduce? | Fission, Budding, Fragmentation and Regeneration

How Do Organisms Reproduce?

Fission, Budding, Fragmentation and Regeneration

Class 10 Science | CBSE + Foundation + Competitive Preparation

Fission, Budding, Fragmentation and Regeneration

1. Introduction | परिचय

English

Fission, budding, fragmentation and regeneration are important forms of asexual reproduction found in different organisms.

In asexual reproduction, generally one parent is involved and there is no fusion of male and female gametes.

हिन्दी

विखंडन, मुकुलन, खंडन और पुनर्जनन अलैंगिक जनन की महत्वपूर्ण विधियाँ हैं।

अलैंगिक जनन में सामान्यतः एक जनक भाग लेता है और नर तथा मादा युग्मकों का संलयन नहीं होता।

CBSE Golden Point: Asexual reproduction generally involves one parent and does not involve fusion of gametes.

याद रखें: एक जनक + युग्मक संलयन नहीं = सामान्यतः अलैंगिक जनन।

2. Fission | विखंडन

Fission is a type of asexual reproduction in which a parent organism divides to form new daughter organisms.

विखंडन में एक जनक जीव विभाजित होकर नई संतति बनाता है।

Fission is mainly of two types:

• Binary Fission — दो संतति
• Multiple Fission — अनेक संतति

3. Binary Fission | द्विखंडन

English

In binary fission, one parent organism divides into two daughter organisms.

Amoeba is a common example.

The nucleus divides first, followed by division of the cytoplasm.

हिन्दी

द्विखंडन में एक जनक जीव विभाजित होकर दो संतति जीव बनाता है।

अमीबा इसका प्रमुख उदाहरण है।

सबसे पहले केंद्रक का विभाजन होता है और उसके बाद कोशिकाद्रव्य का विभाजन होता है।

Animated Binary Fission in Amoeba

Parent Amoeba → Nuclear Division → Cytoplasmic Division → 2 Daughter Amoebae

4. Multiple Fission | बहुखंडन

In multiple fission, one parent organism produces many daughter cells during a reproductive event.

Example: Plasmodium.

बहुखंडन में एक जनक जीव से एक साथ अनेक संतति कोशिकाएँ बन सकती हैं।

Binary = Two
Multiple = Many

Amoeba → Binary Fission
Plasmodium → Multiple Fission

5. Budding | मुकुलन

In budding, a small outgrowth called a bud develops on the parent body.

The bud grows because of repeated cell division and may eventually separate from the parent to form a new organism.

Examples: Hydra and Yeast.

हिन्दी

मुकुलन में जनक के शरीर पर एक छोटी उभार जैसी संरचना मुकुल (Bud) बनती है।

यह मुकुल कोशिका विभाजन द्वारा बढ़ता है और बाद में अलग होकर नया जीव बना सकता है।

उदाहरण: हाइड्रा और यीस्ट।

Animated Budding in Hydra

Parent Hydra → Bud Formation → Bud Growth → Separation → New Hydra

6. Budding in Yeast | यीस्ट में मुकुलन

Yeast is a unicellular fungus. During budding, a small bud develops from the parent cell. The nucleus divides and one daughter nucleus enters the developing bud.

The bud grows and may eventually separate from the parent cell.

यीस्ट एक एककोशिकीय कवक है। मुकुलन के दौरान जनक कोशिका पर एक छोटा मुकुल बनता है। केंद्रक विभाजित होता है और एक नया केंद्रक मुकुल में चला जाता है।

7. Fragmentation | खंडन

Fragmentation occurs when the body of an organism breaks into two or more fragments.

Under suitable conditions, the fragments can grow into new organisms.

Example: Spirogyra.

हिन्दी

खंडन में जीव का शरीर दो या अधिक खंडों में टूट जाता है। उपयुक्त परिस्थितियों में प्रत्येक उपयुक्त खंड से नया जीव विकसित हो सकता है।

उदाहरण: स्पाइरोगाइरा।

Animated Fragmentation in Spirogyra

Why can Spirogyra reproduce by fragmentation?
Spirogyra has a simple filamentous body. Its body can break into fragments and suitable fragments can grow into complete filaments.

स्पाइरोगाइरा का शरीर सरल तंतु के रूप में होता है, इसलिए उसके खंडों से नए तंतु विकसित हो सकते हैं।

8. Regeneration | पुनर्जनन

Regeneration is the ability of an organism to regrow lost or damaged body parts.

In some simple organisms, if the body is cut into pieces, the pieces can develop into complete organisms.

Example: Planaria.

हिन्दी

पुनर्जनन वह क्षमता है जिसमें जीव अपने खोए या क्षतिग्रस्त भागों को पुनः विकसित कर सकता है।

कुछ सरल जीवों में शरीर के अलग-अलग टुकड़े पूर्ण नए जीवों में विकसित हो सकते हैं।

उदाहरण: प्लेनेरिया।

Animated Regeneration in Planaria

9. Regeneration is Not Always Reproduction

This is an important CBSE concept.

Regeneration means regrowth of lost or damaged body parts. It does not always result in a new organism.

For example, if an organism simply regrows a lost body part, it is regeneration but not reproduction.

However, in organisms such as Planaria, separated pieces may develop into complete organisms. In such a case, regeneration also acts as a form of reproduction.

10. Fission vs Budding vs Fragmentation vs Regeneration

Feature	Fission	Budding	Fragmentation	Regeneration
Basic process	Parent divides	Bud develops	Body breaks into fragments	Lost parts regrow
Example	Amoeba	Hydra	Spirogyra	Planaria
Number of new individuals	Two or many	Usually one per bud	Depends on fragments	Depends on organism and fragments
Important feature	Division	Outgrowth	Breaking into pieces	Regrowth

11. Reproduction Process Flow

Parent Organism

→

DNA Copying

→

Fission / Bud / Fragment

→

Growth

→

New Organism

12. DNA Copying and Variations

Reproduction requires the transmission of genetic information. Therefore, DNA must be copied.

DNA copying is highly accurate but is not perfectly error-free. Small differences may therefore arise.

These differences are called variations.

Asexual reproduction generally produces less variation than sexual reproduction because genetic material usually comes from only one parent.

हिन्दी

जनन के दौरान आनुवंशिक सूचना को नई संतति तक पहुँचाने के लिए DNA की प्रतिलिपि बनती है।

DNA copying पूर्णतः त्रुटिरहित नहीं होती, इसलिए छोटे परिवर्तन उत्पन्न हो सकते हैं जिन्हें विविधताएँ कहा जाता है।

DNA Copying → Small Changes → Variations → Possible Adaptation

13. Advantages of These Asexual Methods

• Only one parent is generally required.
• Reproduction can be rapid.
• Large numbers of organisms can be produced.
• Useful characteristics of the parent can be maintained.
• Simple organisms can reproduce without producing gametes.
• Vegetative methods can rapidly multiply suitable plants.

14. Limitations

• Usually less variation is produced.
• Less variation may reduce adaptability to major environmental changes.
• Genetically similar individuals may be similarly affected by certain diseases or environmental stresses.

15. 30 MCQs | Multiple Choice Questions

Q1. Fission is a type of:

A) Sexual reproduction

B) Asexual reproduction

C) Fertilisation

D) Pollination

Answer: B — Fission is an asexual mode of reproduction.

Q2. Binary fission produces:

A) Two daughter organisms

B) Many spores

C) One bud

D) Four gametes

Answer: A

Q3. Binary fission is commonly observed in:

A) Hydra

B) Amoeba

C) Spirogyra

D) Planaria

Answer: B

Q4. Multiple fission produces:

A) One daughter

B) Two daughters

C) Many daughter cells

D) No offspring

Answer: C

Q5. Which organism is associated with multiple fission?

A) Plasmodium

B) Hydra

C) Yeast

D) Potato

Answer: A

Q6. Budding involves formation of:

A) Fragment

B) Bud

C) Sporangium

D) Gamete

Answer: B

Q7. Hydra reproduces commonly by:

A) Budding

B) Fragmentation

C) Multiple fission

D) Spore formation

Answer: A

Q8. Yeast commonly reproduces by:

A) Fragmentation

B) Budding

C) Multiple fission

D) Regeneration

Answer: B

Q9. Fragmentation is commonly seen in:

A) Amoeba

B) Spirogyra

C) Hydra

D) Plasmodium

Answer: B

Q10. Planaria is associated with:

A) Regeneration

B) Binary fission

C) Budding only

D) Multiple fission

Answer: A

Q11. In binary fission, the first major division generally involves:

A) Cell wall

B) Nucleus

C) Vacuole

D) Cell membrane only

Answer: B

Q12. Fragmentation means:

A) Formation of gametes

B) Breaking of body into fragments

C) Formation of pollen

D) Fusion of cells

Answer: B

Q13. Which process involves a small outgrowth on the parent?

A) Budding

B) Fission

C) Fragmentation

D) Fertilisation

Answer: A

Q14. Regeneration means:

A) Formation of spores

B) Regrowth of lost or damaged parts

C) Fusion of gametes

D) Formation of flowers

Answer: B

Q15. Which pair is correctly matched?

A) Amoeba — Binary fission

B) Hydra — Fragmentation

C) Spirogyra — Budding

D) Planaria — Multiple fission

Answer: A

Q16. Which pair is correctly matched?

A) Plasmodium — Multiple fission

B) Yeast — Fragmentation

C) Hydra — Binary fission

D) Amoeba — Budding

Answer: A

Q17. Which process generally produces two daughter cells?

A) Multiple fission

B) Binary fission

C) Budding

D) Regeneration

Answer: B

Q18. Asexual reproduction generally involves:

A) One parent

B) Two parents

C) Three parents

D) No parent

Answer: A

Q19. Which process can produce a new organism from a fragment?

A) Fragmentation

B) Pollination

C) Fertilisation

D) Meiosis only

Answer: A

Q20. In Hydra, the new organism develops initially as:

A) A spore

B) A bud

C) A seed

D) A gamete

Answer: B

Q21. Which organism has a filamentous body?

A) Spirogyra

B) Amoeba

C) Hydra

D) Planaria

Answer: A

Q22. Which process is particularly associated with the breaking of a filament?

A) Fragmentation

B) Budding

C) Binary fission

D) Fertilisation

Answer: A

Q23. DNA copying during reproduction:

A) Is perfectly error-free

B) Never occurs

C) May introduce small variations

D) Occurs only in animals

Answer: C

Q24. Asexual reproduction generally produces:

A) Greater variation

B) Less variation

C) No DNA

D) Only gametes

Answer: B

Q25. Which is NOT a characteristic of asexual reproduction?

A) One parent generally involved

B) No gamete fusion

C) Usually less variation

D) Fusion of male and female gametes

Answer: D

Q26. Regeneration becomes reproductive when:

A) A body part grows slightly

B) A separated part develops into a complete organism

C) DNA disappears

D) Gametes fuse

Answer: B

Q27. Which process is based on an outgrowth?

A) Budding

B) Fragmentation

C) Binary fission

D) Multiple fission

Answer: A

Q28. Which process is based on division into two?

A) Budding

B) Binary fission

C) Fragmentation

D) Regeneration

Answer: B

Q29. Which of the following can be considered both regeneration and reproduction in some organisms?

A) Planaria

B) Amoeba

C) Plasmodium

D) Yeast

Answer: A

Q30. Which sequence is correct for budding?

A) Bud formation → Growth → Separation

B) Fragmentation → Fertilisation → Seed

C) Gamete fusion → Bud → Spore

D) Pollination → Fragmentation → Bud

Answer: A

16. 30 Subjective Questions with Answers

2 Marks Q1. What is fission?

Fission is a type of asexual reproduction in which a parent organism divides to form new daughter organisms.

2 Marks Q2. Define binary fission with an example.

Binary fission is the division of one parent organism into two daughter organisms. Example: Amoeba.

2 Marks Q3. What is multiple fission?

Multiple fission is an asexual reproduction process in which one parent produces many daughter cells. Example: Plasmodium.

2 Marks Q4. What is budding?

Budding is a process in which a small outgrowth called a bud develops on the parent body and grows into a new organism.

2 Marks Q5. Give two examples of organisms showing budding.

Hydra and Yeast.

2 Marks Q6. What is fragmentation?

Fragmentation is the breaking of an organism's body into fragments, from which new organisms can develop under suitable conditions. Example: Spirogyra.

3 Marks Q7. Explain binary fission in Amoeba.

The nucleus first divides into two. The cytoplasm then divides around the two nuclei. Two daughter Amoebae are finally formed.

3 Marks Q8. Explain multiple fission with an example.

In multiple fission, the nucleus undergoes repeated divisions and the parent produces many daughter cells during one reproductive event. Plasmodium is an example.

3 Marks Q9. Explain budding in Hydra.

A small bud develops on the parent Hydra. The bud grows through cell division and develops into a young Hydra. It may finally separate from the parent.

3 Marks Q10. Explain fragmentation in Spirogyra.

Spirogyra has a filamentous body. The filament can break into fragments. Under suitable conditions, each suitable fragment grows into a new filament.

3 Marks Q11. What is regeneration?

Regeneration is the ability to regrow lost or damaged body parts. In some organisms such as Planaria, separated pieces can form complete new organisms.

3 Marks Q12. Why is regeneration not always reproduction?

Regeneration may only restore a lost body part without producing a new individual. It becomes reproductive when a separated part develops into a complete new organism.

4 Marks Q13. Differentiate between binary fission and multiple fission.

Binary Fission	Multiple Fission
Produces two daughter organisms.	Produces many daughter cells.
Example: Amoeba	Example: Plasmodium
Division results in two main units.	Repeated nuclear divisions can be followed by cytoplasmic division.

4 Marks Q14. Differentiate between budding and fragmentation.

Budding: A small outgrowth develops on the parent body. Example: Hydra and Yeast.

Fragmentation: The body breaks into fragments and suitable fragments can form new organisms. Example: Spirogyra.

4 Marks Q15. Explain budding in Yeast.

A small bud develops on the parent yeast cell. The nucleus divides and one daughter nucleus enters the developing bud. The bud grows and may eventually separate from the parent cell.

4 Marks Q16. Why is Spirogyra able to reproduce by fragmentation?

Spirogyra has a simple filamentous body. When the filament breaks into fragments, suitable fragments can continue growth and form complete filaments.

4 Marks Q17. Explain regeneration in Planaria.

Planaria has a strong regenerative ability. When its body is divided into pieces, the pieces can regenerate missing parts. Under suitable conditions, separated pieces can develop into complete Planaria.

5 Marks Q18. Describe the major methods covered in this topic.

• Binary fission — Amoeba.
• Multiple fission — Plasmodium.
• Budding — Hydra and Yeast.
• Fragmentation — Spirogyra.
• Regeneration — Planaria.

5 Marks Q19. Compare fission, budding and fragmentation.

Fission	Budding	Fragmentation
Parent divides.	Bud develops.	Body breaks into fragments.
Amoeba	Hydra / Yeast	Spirogyra
Two or many offspring.	New organism develops from bud.	Suitable fragments can form organisms.

5 Marks Q20. Explain the role of DNA copying in asexual reproduction.

DNA contains hereditary information. During reproduction, DNA must be copied so that genetic information is transmitted to the new organism. The copying process is not perfectly error-free, so small variations may arise.

5 Marks Q21. Why does asexual reproduction generally produce less variation?

In asexual reproduction, genetic material generally comes from one parent. There is no fusion and mixing of genetic material from two different parents. Therefore, variation is generally lower, although small changes can arise during DNA copying.

6 Marks Q22. Explain binary fission in detail with a suitable diagram.

Binary fission is asexual reproduction in which one parent divides into two daughter organisms.

In Amoeba, the nucleus first divides into two. The cytoplasm then divides around the two nuclei. Finally, two daughter Amoebae are formed.

Sequence: Parent → Nuclear division → Cytoplasmic division → Two daughter cells.

6 Marks Q23. Explain budding in Hydra in detail.

A small outgrowth called a bud develops on the body of Hydra. The bud grows due to repeated cell division and gradually develops tentacles and other structures. When fully developed, it may separate from the parent and live independently.

Thus, budding is an asexual mode of reproduction.

6 Marks Q24. Explain fragmentation and regeneration with examples.

Fragmentation: The body breaks into fragments and suitable fragments develop into new organisms. Example: Spirogyra.

Regeneration: An organism regrows lost or damaged parts. In Planaria, separated pieces can develop into complete individuals.

6 Marks Q25. Differentiate between regeneration and reproduction.

Regeneration is the restoration of lost or damaged body parts. Reproduction is the biological process of producing new individuals.

Regeneration becomes a form of reproduction when separated pieces develop into complete new organisms, as seen in Planaria.

6 Marks Q26. Explain why asexual reproduction is advantageous for simple organisms.

• Only one parent is generally required.
• No gamete formation or fusion is required.
• It can be rapid.
• Many offspring can be produced.
• Simple body organisation can make direct reproduction possible.

6 Marks Q27. Explain the relationship between DNA copying and variation.

DNA contains hereditary information and must be copied during reproduction. The copying process is highly accurate but not perfectly error-free. Small differences can therefore arise in DNA.

These differences produce variations. Some variations may help an organism survive changing environmental conditions.

6 Marks Q28. A student says that every fragment produced during fragmentation will always form a new organism. Is this correct?

No. Fragmentation leads to reproduction only when the organism has the ability to regenerate and the fragments remain viable under suitable conditions. Therefore, not every fragment of every organism necessarily forms a complete new individual.

6 Marks Q29. A Planaria is cut into several pieces. Explain what may happen.

Planaria has a strong regenerative ability. The pieces can regenerate missing structures. Under suitable conditions, separated pieces can develop into complete Planaria. Therefore, regeneration can also act as a mode of reproduction in this organism.

6 Marks Q30. Explain all four processes using one key word for each.

Fission → Division

Budding → Outgrowth

Fragmentation → Breaking

Regeneration → Regrowth

Examples: Amoeba → Fission, Hydra → Budding, Spirogyra → Fragmentation, Planaria → Regeneration.

17. HOTS / Competency-Based Questions

HOTS 1: A student observes an organism dividing into two almost equal parts. Which reproductive method is likely being observed?

The process is likely binary fission. Amoeba is a common example.

HOTS 2: An organism develops a small projection on its body. The projection grows and later separates. Identify the process.

The process is budding. Hydra and Yeast show budding.

HOTS 3: A filamentous organism breaks into several pieces and each piece grows. Identify the process and organism.

The process is fragmentation and the organism is Spirogyra.

HOTS 4: Why is Planaria an important example while studying regeneration?

Planaria has a remarkable ability to regenerate. Separated pieces can develop into complete organisms under suitable conditions, so regeneration can also serve as reproduction.

18. Important Diagram Labelling

Binary Fission in Amoeba:

• Parent Amoeba
• Nucleus
• Dividing nucleus
• Cytoplasm
• Daughter cells

Budding in Hydra:

• Parent Hydra
• Bud
• Tentacles
• Young Hydra

Fragmentation in Spirogyra:

• Parent filament
• Fragment
• New filament

Regeneration in Planaria:

• Planaria
• Body fragment
• Regenerated structures
• Complete organism

19. CBSE Golden Points | परीक्षा के लिए महत्वपूर्ण बिंदु

1. Fission is an asexual mode of reproduction.
2. Binary fission produces two daughter organisms.
3. Amoeba → Binary fission.
4. Multiple fission produces many daughter cells.
5. Plasmodium → Multiple fission.
6. Budding involves a small outgrowth called a bud.
7. Hydra → Budding.
8. Yeast → Budding.
9. Spirogyra → Fragmentation.
10. Planaria → Regeneration.
11. Fragmentation means breaking of the body into fragments.
12. Regeneration means regrowth of lost or damaged body parts.
13. Regeneration is not always reproduction.
14. In Planaria, separated pieces can form complete organisms.
15. DNA copying is not perfectly error-free.
16. Small DNA-copying differences can produce variations.
17. Asexual reproduction generally produces less variation than sexual reproduction.

20. Easy Memory Trick | याद रखने की ट्रिक

“F-B-F-R”

F → Fission → Amoeba
B → Budding → Hydra / Yeast
F → Fragmentation → Spirogyra
R → Regeneration → Planaria

Division → Outgrowth → Breaking → Regrowth

21. One-Line Revision

Amoeba → Binary Fission

Plasmodium → Multiple Fission

Hydra / Yeast → Budding

Spirogyra → Fragmentation

Planaria → Regeneration

Fission = Division | Budding = Outgrowth | Fragmentation = Breaking | Regeneration = Regrowth

22. Final Concept Flow

Asexual Reproduction

→

Fission

→

Budding

→

Fragmentation

→

Regeneration

Final Exam Revision

Fission involves division of the parent organism, budding involves formation of an outgrowth, fragmentation involves breaking into fragments and regeneration involves regrowth of lost or damaged parts.

Amoeba → Fission | Hydra → Budding | Spirogyra → Fragmentation | Planaria → Regeneration