Which part of the flower contains the male germ-cell?

Correct Option: D. Solution: The pollen grains contain the male germ-cell.

How do Organisms Reproduce

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CBSE Learning Objectives – Key Concepts & Skills You Must Know

Learning Objectives

Understand the significance of reproduction in organisms.
Explain the process of DNA copying in reproduction.
Differentiate between asexual and sexual reproduction.
Describe various modes of reproduction in unicellular and multicellular organisms.
Identify the structures involved in human reproductive systems.
Discuss the importance of variation in populations for survival.
Analyze the methods of contraception and their implications.

CBSE Revision Notes & Quick Summary for Last-Minute Study

How do Organisms Reproduce?

Introduction

Reproduction is not essential for the survival of an individual organism but is crucial for the continuation of a species.
Organisms reproduce to create new individuals, which leads to population stability.

7.1 Do Organisms Create Exact Copies of Themselves?

Organisms share similar body designs due to similar blueprints in their DNA.
Reproduction involves making copies of DNA, which may lead to variations.
Variations are important for evolution and survival of species.

Importance of Variation

Variations allow populations to adapt to changing environments, ensuring survival.

7.2 Modes of Reproduction Used by Single Organisms

Asexual Reproduction

New generations can be created from a single individual.
Examples include:
- Fission: Unicellular organisms like bacteria and protozoa divide into two or more daughter cells.
- Budding: Organisms like hydra produce buds that develop into new individuals.
- Vegetative Propagation: Plants like Bryophyllum develop new plants from roots, stems, or leaves.

Fission

Binary Fission: Seen in organisms like Amoeba and Leishmania.
- Amoeba: Splits into two equal halves.
- Leishmania: Divides in a definite orientation.

7.3 Sexual Reproduction

Involves two individuals (male and female) to create new generations.
Significance:
- Increases genetic variation, enhancing survival chances of the species.

Diagram Descriptions

Binary Fission in Amoeba: Stages of cell division from a single cell to two daughter cells.
Budding in Hydra: Stages from a simple hydra to a new bud.
Fertilization in Flowers: Involves pollen grain, stigma, pollen tube, and ovary.
Germinating Seed: Shows plumule (future shoot) and radicle (future root).
Life Cycle of a Tapeworm: Stages of development from a mature segment to a mature tapeworm.

CBSE Exam Tips, Important Questions & Common Mistakes to Avoid

Common Mistakes and Exam Tips

Common Pitfalls

Misunderstanding Asexual vs. Sexual Reproduction: Many students confuse asexual reproduction (e.g., budding in yeast, fission in bacteria) with sexual reproduction, which involves two parents. Ensure you can differentiate between these modes.
Ignoring the Role of DNA in Reproduction: Students often overlook the importance of DNA copying in reproduction. Remember that variations in DNA are crucial for evolution and survival of species.
Confusing Pollination and Fertilization: Pollination is the transfer of pollen from the anther to the stigma, while fertilization is the fusion of male and female gametes. Be clear on these definitions.
Overlooking the Importance of Contraceptive Methods: Many students fail to recognize the various contraceptive methods and their implications for preventing pregnancy and sexually transmitted diseases.

Exam Tips

Draw Diagrams: Practice drawing and labeling diagrams of reproductive systems (e.g., male and female reproductive systems, flower structure) as they can help clarify your understanding and are often required in exams.
Use Examples: When answering questions about reproduction, use specific examples (e.g., yeast for budding, Amoeba for fission) to illustrate your points.
Understand Key Terms: Make sure you know key terms such as gametes, zygote, meiosis, and vegetative propagation, as these are frequently tested.
Review Past Questions: Familiarize yourself with common exam questions related to reproduction, such as the advantages of sexual reproduction or the differences between various reproductive methods.

CBSE Quiz & Practice Test – MCQs, True/False Questions with Solutions

Multiple Choice Questions

Faster reproduction rate

Increased genetic variation

Requirement of only one parent

Higher energy efficiency

Correct Answer: B

Solution:

The primary advantage of sexual reproduction is increased genetic variation, which can enhance the adaptability and survival of a species in changing environments.

First stage

Second stage

Third stage

Fourth stage

Correct Answer: B

Solution:

In the second stage of budding in hydra, a small bulge begins to form on the side of the hydra, representing the initial stage of a new individual.

The nucleus duplicates

The cell membrane constricts

The cell splits into two

The cell forms a bud

Correct Answer: B

Solution:

After the cell elongates, the cell membrane starts to constrict in the center, preparing to divide.

They kill bacteria and viruses on contact.

They provide a physical barrier that reduces the risk of transmission.

They alter the hormonal balance in the body.

They prevent the release of gametes.

Correct Answer: B

Solution:

Condoms act as a physical barrier that prevents the exchange of bodily fluids, thereby reducing the risk of transmission of sexually transmitted diseases.

Copper-T

Hormonal pills

Condom

Vasectomy

Correct Answer: C

Solution:

Condoms act as a mechanical barrier to prevent sperm from reaching the egg, thus preventing fertilization.

Using hormonal pills

Using a condom

Undergoing surgical sterilization

Practicing abstinence

Correct Answer: B

Solution:

Using a condom during intercourse helps to prevent the transmission of many sexually transmitted infections.

Budding

Fragmentation

Binary fission

Multiple fission

Correct Answer: B

Solution:

Spirogyra reproduces asexually through fragmentation, where the organism breaks into fragments that grow into new individuals.

It creates identical copies of the parent organism.

It leads to genetic variation in offspring.

It requires only one parent organism.

It is faster than asexual reproduction.

Correct Answer: B

Solution:

Sexual reproduction involves the combination of genetic material from two parents, leading to genetic variation in the offspring.

Binary fission

Budding

Fragmentation

Spore formation

Correct Answer: B

Solution:

In Hydra, asexual reproduction occurs through budding, where a new organism develops from an outgrowth or bud due to cell division at one particular site.

It ensures the survival of the individual organism.

It allows for the creation of identical offspring.

It provides the blueprint for body design and function.

It prevents genetic variation.

Correct Answer: C

Solution:

DNA copying is essential because it provides the blueprint for body design and function, ensuring that offspring resemble their parents.

To produce eggs

To nourish the embryo

To initiate menstruation

To facilitate binary fission

Correct Answer: B

Solution:

The placenta provides a large surface area for glucose and oxygen to pass from the mother to the embryo.

It produces sperm cells.

It facilitates the exchange of nutrients and waste between mother and embryo.

It forms the embryo's nervous system.

It initiates cell division in the embryo.

Correct Answer: B

Solution:

The placenta is a special tissue that facilitates the exchange of nutrients and waste between the mother's blood and the embryo, supporting its development.

It allows for rapid population growth.

It enables organisms to survive in harsh environments.

It allows organisms to reproduce without a mate.

It enables the replacement of lost or damaged body parts.

Correct Answer: D

Solution:

Regeneration in organisms like Hydra and Planaria primarily allows them to replace lost or damaged body parts, which can also lead to the formation of new individuals.

Asexual reproduction

Binary fission

Sexual reproduction

Budding

Correct Answer: C

Solution:

Sexual reproduction involves the combination of genetic material from two different individuals, increasing genetic variation within a population.

It produces pollen grains.

It is where pollen grains land and germinate.

It contains the ovules.

It develops into a seed.

Correct Answer: B

Solution:

The stigma is the part of the flower where pollen grains land and germinate, allowing the pollen tube to grow towards the ovary.

Budding

Binary fission

Multiple fission

Fragmentation

Correct Answer: C

Solution:

Plasmodium reproduces through multiple fission, where one cell divides into many daughter cells simultaneously.

Budding

Binary fission

Fragmentation

Spore formation

Correct Answer: A

Solution:

Budding is a form of asexual reproduction where a new organism develops from a small projection on the parent organism, as seen in yeast and hydra.

To maintain the life of an individual organism

To create more individuals and ensure species survival

To provide nutrition to the organism

To eliminate waste from the organism

Correct Answer: B

Solution:

Reproduction is primarily aimed at creating more individuals to ensure the survival of the species.

It allows organisms to grow larger.

It ensures that offspring have the same number of chromosomes as their parents.

It provides energy for cellular processes.

It assists in nutrient absorption.

Correct Answer: B

Solution:

DNA copying is essential for reproduction because it ensures that offspring inherit the correct number of chromosomes and genetic information from their parents.

It thickens further

It remains unchanged

It breaks down and is expelled

It becomes a placenta

Correct Answer: C

Solution:

If the egg is not fertilised, the uterine lining breaks down and is expelled as menstruation.

Formation of a single daughter cell

Simultaneous formation of multiple daughter cells

Budding of a new organism

Binary fission into two cells

Correct Answer: B

Solution:

Multiple fission in Plasmodium results in the simultaneous formation of multiple daughter cells, which is different from binary fission or budding.

To provide energy for cellular functions.

To serve as a blueprint for protein synthesis and inheritance of traits.

To create new cellular organelles.

To eliminate mutations from the genetic material.

Correct Answer: B

Solution:

DNA serves as a blueprint for protein synthesis and is responsible for the inheritance of traits from parents to offspring, making it essential for reproduction.

It involves the fusion of gametes.

It requires a single parent organism.

It involves the growth of a new organism from a fragment of the parent.

It is exclusive to plants.

Correct Answer: C

Solution:

Regeneration involves the growth of a new organism from a fragment of the parent, as seen in organisms like Hydra and Planaria.

To provide energy for cellular processes

To serve as a blueprint for body design

To transport nutrients

To act as a barrier against infections

Correct Answer: B

Solution:

DNA serves as a blueprint for body design, ensuring that offspring have similar body designs to their parents.

Condoms

Copper-T

Oral pills

Surgical methods

Correct Answer: C

Solution:

Oral pills work by changing the hormonal balance in the body, thereby preventing the release of eggs and subsequent fertilization.

Increased genetic variation in a population.

Immediate death of the organism.

Formation of identical clones.

Complete halt of cellular processes.

Correct Answer: A

Solution:

Errors in DNA copying can introduce variations in the genetic makeup of organisms. These variations contribute to genetic diversity within a population, which can be beneficial for adaptation and survival.

To provide energy for cellular processes

To store genetic information for inheritance

To aid in digestion

To transport nutrients

Correct Answer: B

Solution:

DNA contains the genetic blueprint for the development and function of living organisms, and it is crucial for the inheritance of traits from parents to offspring.

Sepals

Ovules

Pistil

Pollen grains

Correct Answer: D

Solution:

The pollen grains contain the male germ-cell.

Binary fission

Budding

Fragmentation

Multiple fission

Correct Answer: B

Solution:

Yeast reproduces asexually through budding, where small buds form and separate to grow into new individuals.

It requires less energy than asexual reproduction.

It generates more genetic variation, enhancing adaptability.

It guarantees identical offspring.

It is faster than asexual reproduction.

Correct Answer: B

Solution:

Sexual reproduction combines genetic material from two parents, resulting in offspring with genetic variations, which can enhance adaptability and survival in changing environments.

To produce pollen grains

To transport the male germ-cell to the ovule

To protect the ovule

To nourish the embryo

Correct Answer: B

Solution:

The pollen tube grows from the pollen grain and travels through the style to reach the ovary, allowing the male germ-cell to fuse with the female gamete in the ovule.

Budding

Fertilization

Cross-pollination

Conjugation

Correct Answer: A

Solution:

Budding is a form of asexual reproduction where a new organism develops from an outgrowth or bud due to cell division at one particular site.

To attract pollinators.

To produce pollen grains.

To house the female gamete and facilitate fertilization.

To store nutrients for the plant.

Correct Answer: C

Solution:

The ovule contains the female gamete and is the site where fertilization occurs, leading to the formation of a zygote that develops into a seed.

To enhance pleasure

To prevent pregnancy

To prevent sexually transmitted infections

To increase fertility

Correct Answer: C

Solution:

Condoms help to prevent the transmission of sexually transmitted infections.

Condoms

Copper-T

Oral pills

Surgical sterilization

Correct Answer: C

Solution:

Oral pills are a hormonal method of contraception that prevent pregnancy by altering the hormonal balance in the body, thereby preventing ovulation.

It becomes a seed

It forms a pollen tube

It disintegrates

It becomes a fruit

Correct Answer: A

Solution:

After fertilization, the ovule develops into a seed, which contains the embryo of the future plant.

Binary fission

Budding

Multiple fission

Fragmentation

Correct Answer: B

Solution:

Budding is a form of asexual reproduction where a new organism develops from an outgrowth or bud due to cell division at one particular site.

Menstruation begins

Breast size increases

Facial hair begins to grow

Voice remains unchanged

Correct Answer: C

Solution:

During puberty, boys experience the growth of facial hair and changes in their voice.

Elongation, constriction, fission

Constriction, elongation, fission

Fission, elongation, constriction

Elongation, fission, constriction

Correct Answer: A

Solution:

In binary fission, the Amoeba first elongates, then constricts at the center, and finally divides into two daughter cells.

Hormonal pills

Copper-T

Condoms

Surgical sterilization

Correct Answer: C

Solution:

Condoms act as a physical barrier to prevent sperm from reaching the egg, thereby preventing fertilization.

Condom

Copper-T

Oral contraceptive pills

Vasectomy

Correct Answer: A

Solution:

Condoms act as a mechanical barrier that prevents sperm from reaching the egg, thereby preventing fertilization.

Condoms

Oral pills

Copper-T

Surgical methods

Correct Answer: B

Solution:

Oral pills are contraceptive methods that change the hormonal balance to prevent the release of eggs and fertilization.

A complex multicellular organism like a mammal loses a limb.

A simple organism like Planaria is cut into pieces.

A plant loses its leaves due to harsh weather.

A bacterial cell divides into two daughter cells.

Correct Answer: B

Solution:

Regeneration is most likely to occur in simple organisms like Planaria, where specialized cells can proliferate and differentiate to form a complete organism from a part.

Sepals

Ovules

Pistil

Anther

Correct Answer: D

Solution:

The anther is the part of the flower that contains pollen grains.

The nucleus duplicates

The cell splits into two daughter cells

The cell membrane constricts

The cell wall thickens

Correct Answer: C

Solution:

After the cell elongates during binary fission in Amoeba, the cell membrane starts to constrict in the center, preparing to divide the cell into two daughter cells.

DNA copying is always error-free, ensuring identical offspring.

DNA copying errors are beneficial as they introduce variations.

Errors in DNA copying always result in non-viable offspring.

DNA copying errors are corrected by the organism's immune system.

Correct Answer: B

Solution:

DNA copying is not absolutely accurate, and the resultant errors introduce variations that can be beneficial for the survival of species by creating diversity within a population.

To produce sperm cells.

To facilitate the exchange of nutrients and waste between the mother and the embryo.

To initiate menstruation.

To prevent fertilization of the egg.

Correct Answer: B

Solution:

The placenta facilitates the exchange of nutrients and waste products between the mother's blood and the developing embryo, providing essential support for fetal development.

Formation of pollen tube

Development of petals

Formation of zygote

Growth of style

Correct Answer: C

Solution:

The fusion of male and female gametes in flowering plants results in the formation of a zygote, which can develop into a new plant.

Increased hair growth in armpits and genital areas.

Development of secondary sexual characteristics.

Immediate cessation of body growth.

Onset of menstruation in girls.

Correct Answer: C

Solution:

Puberty is associated with the development of secondary sexual characteristics, increased hair growth in specific areas, and the onset of menstruation in girls. However, body growth does not immediately cease during puberty; it continues, although at a slower rate.

Ovary

Uterus

Vagina

Fallopian tube

Correct Answer: D

Solution:

Fertilization typically occurs in the fallopian tube, where the sperm meets the egg.

Increased genetic diversity

Reduced seed production

Increased self-fertilization

Decreased plant height

Correct Answer: A

Solution:

Cross-pollination involves the transfer of pollen from one flower to another, leading to increased genetic diversity among the offspring.

Photosynthesis

Pollination

Transpiration

Respiration

Correct Answer: B

Solution:

Pollination is the process by which pollen is transferred from the stamen to the stigma, leading to fertilization and the formation of seeds.

Constriction, Elongation, Fission

Elongation, Constriction, Fission

Fission, Elongation, Constriction

Elongation, Fission, Constriction

Correct Answer: B

Solution:

In binary fission, the cell first elongates, then the membrane constricts, and finally the cell splits into two daughter cells.

Through a tube that grows from the pollen grain to the ovary.

By direct contact with the ovule.

By being absorbed into the ovule.

Through diffusion across the style.

Correct Answer: A

Solution:

After landing on a suitable stigma, a pollen tube grows from the pollen grain through the style to the ovary, allowing the male germ-cell to reach the female gamete.

It transports water to the ovary.

It facilitates the transfer of pollen from the anther to the stigma.

It grows from the pollen grain to deliver sperm cells to the ovule.

It supports the structure of the flower during fertilization.

Correct Answer: C

Solution:

The pollen tube grows from the pollen grain after it lands on a suitable stigma, and it facilitates the delivery of sperm cells to the ovule for fertilization.

Amoeba

Yeast

Plasmodium

Leishmania

Correct Answer: B

Solution:

Yeast reproduces asexually through the process of budding.

Hormonal pills

Condoms

Copper-T insertion

Surgical sterilization

Correct Answer: B

Solution:

Condoms create a mechanical barrier that prevents sperm from reaching the egg, thereby preventing fertilization.

Cross-pollination

Self-pollination

Double fertilization

Germination

Correct Answer: B

Solution:

Self-pollination is the transfer of pollen from the stamen to the stigma of the same flower, whereas cross-pollination involves the transfer between different flowers.

It immediately fertilizes the ovule

It forms a pollen tube to reach the ovary

It falls off the flower

It dries up and dies

Correct Answer: B

Solution:

After landing on a suitable stigma, the pollen grain forms a tube that grows through the style to reach the ovary, where fertilization occurs.

Prevention of sperm reaching the egg

Blocking of fallopian tubes

Prevention of egg release

Removal of uterus lining

Correct Answer: C

Solution:

Hormonal contraceptives work by altering the hormonal balance, preventing the release of eggs from the ovaries.

It becomes a seed.

It shrivels and falls off.

It grows into a fruit.

It becomes the pollen tube.

Correct Answer: C

Solution:

After fertilization, the ovary grows rapidly and ripens to form a fruit.

Condoms

Hormonal pills

Copper-T

Vasectomy

Correct Answer: A

Solution:

Condoms act as a mechanical barrier that prevents sperm from reaching the egg, thereby preventing fertilization. Hormonal pills alter hormonal balance, Copper-T is an intrauterine device, and vasectomy is a surgical method.

It nourishes the embryo

It protects the embryo from infections

It helps in the movement of the embryo

It facilitates the division of the embryo

Correct Answer: A

Solution:

The placenta provides a large surface area for glucose and oxygen to pass from the mother to the embryo, nourishing it.

Errors in DNA copying mechanisms

Environmental factors affecting DNA

Mutations caused by external agents

Selective breeding practices

Correct Answer: A

Solution:

Variations in a population primarily arise due to errors in the DNA copying mechanisms during reproduction. These errors, while mostly corrected, introduce small variations that accumulate over generations, leading to diversity within a species.

Ovary

Uterus

Vas deferens

Fallopian tube

Correct Answer: C

Solution:

The vas deferens is part of the male reproductive system, not the female reproductive system.

It generates genetic variation, which can enhance survival in changing environments.

It requires less energy and resources than asexual reproduction.

It ensures that offspring are identical to the parent organism.

It allows organisms to reproduce faster than asexual reproduction.

Correct Answer: A

Solution:

Sexual reproduction combines genetic material from two parents, resulting in offspring with genetic variations that can be beneficial for adaptation and survival in changing environments.

It transports the male gamete to the female gamete.

It provides nutrients to the developing seed.

It protects the ovule from external damage.

It facilitates the dispersal of seeds.

Correct Answer: A

Solution:

The pollen tube grows from the pollen grain on the stigma and travels through the style to reach the ovary, where it delivers the male gamete to the female gamete for fertilization.

They can cause side effects due to changes in hormonal balance.

They provide a permanent solution to prevent pregnancy.

They increase the risk of sexually transmitted diseases.

They require surgical intervention for effectiveness.

Correct Answer: A

Solution:

Hormonal contraceptives work by altering the hormonal balance to prevent ovulation, which can lead to side effects.

Regeneration involves the growth of a new organism from a fragment of the parent.

Regeneration is a form of reproduction that requires two parents.

Regeneration results in offspring that are genetically different from the parent.

Regeneration requires the presence of a host organism for completion.

Correct Answer: A

Solution:

Regeneration is an asexual reproduction process where a new organism grows from a fragment of the parent organism, as seen in organisms like Hydra.

To maintain the life of an individual organism.

To ensure the survival of the species through the creation of new individuals.

To increase the energy expenditure of an organism.

To eliminate variations within a species.

Correct Answer: B

Solution:

Organisms reproduce to ensure the survival of the species by creating new individuals, which is crucial for the continuation of the species.

It produces hormones to maintain pregnancy.

It provides a large surface area for nutrient and gas exchange between the mother and embryo.

It serves as a protective barrier against all infections.

It is the primary organ for waste excretion in the mother.

Correct Answer: B

Solution:

The placenta provides a large surface area for the exchange of nutrients, oxygen, and waste products between the mother's blood and the embryo, facilitating the embryo's development.

A starfish regenerating a lost arm.

A seed growing into a new plant.

A caterpillar transforming into a butterfly.

A frog laying eggs in a pond.

Correct Answer: A

Solution:

Regeneration refers to the ability of an organism to regrow certain parts of its body. A starfish regenerating a lost arm is a classic example of this process, where specialized cells proliferate and differentiate to replace the lost part.

Binary fission

Budding

Fragmentation

Spore formation

Correct Answer: A

Solution:

In Amoeba, asexual reproduction occurs through binary fission, where the cell divides into two equal halves.

Ovary

Uterus

Vas deferens

Fallopian tube

Correct Answer: C

Solution:

The vas deferens is part of the male reproductive system.

Binary fission

Budding

DNA replication

Multiple fission

Correct Answer: C

Solution:

DNA replication is the process of creating a copy of DNA, which is essential for reproduction.

Budding

Binary fission

Multiple fission

Regeneration

Correct Answer: C

Solution:

In Plasmodium, asexual reproduction occurs through multiple fission, where the organism divides into many daughter cells simultaneously.

It requires only one parent.

It generates more genetic variation.

It is faster than asexual reproduction.

It does not require specialized cells.

Correct Answer: B

Solution:

Sexual reproduction allows for the combination of genetic material from two parents, leading to greater genetic variation.

Sepals

Ovules

Pistil

Anther

Correct Answer: D

Solution:

The anther is the part of the flower that contains pollen grains, which are the male gametes.

Ovary

Uterus

Vas deferens

Fallopian tube

Correct Answer: C

Solution:

The vas deferens is part of the male reproductive system, not the female.

To produce hormones for fetal development

To provide a barrier against infections

To facilitate the exchange of nutrients and waste between mother and fetus

To initiate labor contractions

Correct Answer: C

Solution:

The placenta facilitates the exchange of nutrients and waste between the mother's blood and the fetus, providing essential nutrients and oxygen while removing waste products.

To create identical offspring

To provide energy for the cell

To ensure genetic variation

To repair damaged cells

Correct Answer: A

Solution:

DNA copying is essential for creating new individuals that are similar to the parent, ensuring the continuation of the species.

It allows for genetic diversity in crops.

It is a faster method to produce large numbers of plants.

It reduces the need for water and nutrients.

It eliminates the need for pollinators.

Correct Answer: B

Solution:

Vegetative propagation is used because it allows for the rapid production of large numbers of plants with identical characteristics, which is beneficial for maintaining desirable traits in crops.

Hormonal pills

Condoms

Copper-T

Surgical methods

Correct Answer: B

Solution:

Condoms create a mechanical barrier that prevents sperm from reaching the egg, thus avoiding fertilization.

Binary fission in Amoeba results in two genetically identical daughter cells.

Binary fission in Amoeba involves the formation of spores.

Binary fission in Amoeba requires the presence of a host organism.

Binary fission in Amoeba is a form of sexual reproduction.

Correct Answer: A

Solution:

Binary fission in Amoeba is an asexual reproduction process where the organism divides into two genetically identical daughter cells, each inheriting a copy of the parent cell's DNA.

True or False

Correct Answer: True

Solution:

In sexual reproduction, the male germ-cell produced by pollen grain fuses with the female gamete present in the ovule.

Correct Answer: True

Solution:

The stigma is the terminal part of a flower that is often sticky to effectively capture pollen grains.

Correct Answer: True

Solution:

The ovary in a flower contains ovules, and each ovule has an egg cell which can be fertilized by a male germ-cell.

Correct Answer: True

Solution:

Regeneration involves the growth of new individual organisms from the body parts of an organism, as seen in organisms like Hydra and Planaria.

Correct Answer: True

Solution:

Self-pollination involves the transfer of pollen within the same flower, allowing fertilization to occur without the need for external agents.

Correct Answer: False

Solution:

Cross-pollination involves the transfer of pollen from the stamen of one flower to the stigma of another flower.

Correct Answer: True

Solution:

Regeneration allows organisms like Hydra to form new individuals from fragments, as specialized cells proliferate and differentiate to recreate the organism.

Correct Answer: False

Solution:

While condoms can help prevent the transmission of many sexually transmitted infections to some extent, they do not completely eliminate the risk.

Correct Answer: True

Solution:

The placenta facilitates the transfer of nutrients and oxygen from the mother's blood to the embryo, while also removing waste products.

Correct Answer: True

Solution:

Yeast reproduces asexually by forming small buds that grow and eventually separate from the parent cell.

Correct Answer: True

Solution:

Using a condom during sexual intercourse helps prevent the transmission of many sexually transmitted diseases.

Correct Answer: True

Solution:

Condoms act as a mechanical barrier that prevents sperm from reaching the egg and also help reduce the transmission of sexually transmitted diseases.

Correct Answer: True

Solution:

The placenta, with its villi and surrounding blood spaces, provides a large surface area for the transfer of glucose and oxygen from the mother's blood to the embryo.

Correct Answer: True

Solution:

After fertilisation, the zygote divides and forms an embryo, which implants itself in the uterine lining to continue development into a foetus.

Correct Answer: True

Solution:

The placenta provides a large surface area for glucose and oxygen to pass from the mother's blood to the embryo.

Correct Answer: True

Solution:

Cross-pollination involves the transfer of pollen from the stamen of one flower to the stigma of another flower.

Correct Answer: False

Solution:

Self-pollination occurs when pollen is transferred within the same flower, whereas cross-pollination involves the transfer of pollen from one flower to another.

Correct Answer: True

Solution:

In humans, sexual reproduction involves the fusion of a male gamete (sperm) and a female gamete (egg), resulting in the formation of a zygote.

Correct Answer: True

Solution:

The placenta is a specialized tissue that facilitates the transfer of nutrients and oxygen from the mother's blood to the embryo, supporting its development.

Correct Answer: False

Solution:

Reproduction is not necessary for the survival of an individual organism; it is essential for the continuation of a species.

Correct Answer: True

Solution:

Yeast reproduces asexually through a process called budding, where small buds form on the parent organism and eventually separate to grow into new individuals.

Correct Answer: False

Solution:

The vas deferens is part of the male reproductive system, responsible for carrying sperm from the testicles to the urethra.

Correct Answer: True

Solution:

Reproduction at its most basic level involves making copies of the blueprints of body design, which includes creating a DNA copy.

Correct Answer: True

Solution:

Condoms act as a barrier to prevent the exchange of bodily fluids, thereby reducing the risk of transmitting infections like gonorrhoea, syphilis, and HIV-AIDS.

Correct Answer: True

Solution:

Condoms act as a barrier to prevent the exchange of bodily fluids, thereby reducing the risk of transmitting sexually transmitted infections.

Correct Answer: True

Solution:

Contraceptive pills prevent pregnancy by changing the hormonal balance, thereby preventing the release of eggs from the ovaries.

Correct Answer: True

Solution:

In binary fission, an Amoeba starts as a single cell with a prominent nucleus, elongates, and then splits into two daughter cells, each with its own nucleus and cellular structure.

Correct Answer: True

Solution:

Budding in yeast is a form of asexual reproduction where a new organism grows out of the body of the parent.

Correct Answer: True

Solution:

Binary fission in Amoeba involves the division of a single cell into two identical daughter cells, each with its own nucleus.

Correct Answer: False

Solution:

Asexual reproduction involves the creation of new generations from a single individual, without the involvement of another organism.

Correct Answer: True

Solution:

After fertilisation, the zygote divides and develops into an embryo, which is enclosed within a seed.

Correct Answer: True

Solution:

As the rate of general body growth begins to slow down, reproductive tissues begin to mature during puberty.

Correct Answer: False

Solution:

Reproduction is not necessary for the survival of an individual organism. It is essential for the continuation of a species but not for the individual's life processes such as nutrition, respiration, or excretion.

Correct Answer: False

Solution:

In humans, the ovaries release one egg every month, which travels to the uterus through the fallopian tube, not the vas deferens.

Correct Answer: True

Solution:

If the egg is not fertilized, the thickened lining of the uterus is not needed and is shed as blood and mucous, a process known as menstruation.

Correct Answer: False

Solution:

Self-pollination occurs when pollen is transferred within the same flower, not between different flowers.

Correct Answer: False

Solution:

Regeneration involves the ability of an organism to grow into a complete individual from parts of its body, while budding involves the growth of a new individual from a small bulge on the parent organism.

Correct Answer: True

Solution:

In plants, the male germ-cell from the pollen grain fuses with the female gamete in the ovule, resulting in the formation of a zygote.

Correct Answer: True

Solution:

Regeneration in organisms such as Hydra involves specialized cells proliferating to form new individuals from body parts.

Correct Answer: True

Solution:

Yeast reproduces asexually through budding, where a small bud forms on the parent cell and eventually detaches to become a new individual.

Correct Answer: True

Solution:

Condoms act as a mechanical barrier, preventing sperm from reaching the egg, thus preventing pregnancy.

Correct Answer: True

Solution:

In Hydra, budding involves a small bulge forming on the parent organism, which develops into a new individual.

Correct Answer: True

Solution:

If the egg is not fertilised, the thickened lining of the uterus is not needed and is shed from the body as menstruation.

Correct Answer: True

Solution:

DNA contains the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses, including the information for making proteins.

Correct Answer: True

Solution:

Condoms on the penis or similar coverings worn in the vagina serve as mechanical barriers to prevent sperm from reaching the egg.

Correct Answer: True

Solution:

Binary fission is a type of asexual reproduction where a single organism divides into two parts, each becoming a new organism with a nucleus and cellular structures.

Correct Answer: False

Solution:

The vas deferens is part of the male reproductive system, responsible for transporting sperm.

How do Organisms Reproduce

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CBSE Learning Objectives – Key Concepts & Skills You Must Know

Learning Objectives

CBSE Revision Notes & Quick Summary for Last-Minute Study

How do Organisms Reproduce?

Introduction

7.1 Do Organisms Create Exact Copies of Themselves?

Importance of Variation

7.2 Modes of Reproduction Used by Single Organisms

Asexual Reproduction

Fission

7.3 Sexual Reproduction

Diagram Descriptions

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Multiple Choice Questions

Q1.What is the primary advantage of sexual reproduction over asexual reproduction in terms of evolutionary biology?

Correct Answer: B

Q2.During which stage of the hydra's life cycle does a new individual begin to form?

Correct Answer: B

Q3.In the process of binary fission in Amoeba, what happens after the cell elongates?

Correct Answer: B

Q4.Why is the use of condoms considered an effective method for preventing sexually transmitted diseases (STDs)?

Correct Answer: B

Q5.Which of the following is a method of contraception that involves a mechanical barrier?

Correct Answer: C

Q6.Which of the following is a method of preventing sexually transmitted diseases during intercourse?

Correct Answer: B

Q7.Which of the following is a method of asexual reproduction in Spirogyra?

Correct Answer: B

Q8.Which of the following is a consequence of sexual reproduction?

Correct Answer: B

Q9.Which of the following is a method of asexual reproduction in Hydra?

Correct Answer: B

Q10.Why is DNA copying an essential part of the process of reproduction?

Correct Answer: C

Q11.What is the primary function of the placenta during pregnancy?

Correct Answer: B

Q12.What role does the placenta play in the development of a human embryo?

Correct Answer: B

Q13.What is the primary advantage of regeneration in organisms like Hydra and Planaria?

Correct Answer: D

Q14.Which reproductive strategy is most likely to increase genetic variation within a population?

Correct Answer: C

Q15.What is the role of the stigma in the process of pollination?

Correct Answer: B

Q16.Which of the following processes is used by Plasmodium to reproduce?

Correct Answer: C

Q17.Which method of asexual reproduction involves the formation of a new organism from a small projection on the parent organism?

Correct Answer: A

Q18.What is the primary purpose of reproduction in organisms?

Correct Answer: B

Q19.Why is DNA copying an essential part of the reproduction process?

Correct Answer: B

Q20.What happens to the uterine lining if the egg is not fertilised?

Correct Answer: C

Q21.Which of the following is a consequence of multiple fission in Plasmodium?

Correct Answer: B

Q22.What is the primary role of DNA in the process of reproduction?

Correct Answer: B

Q23.How does the process of regeneration differ from other forms of reproduction?

Correct Answer: C

Q24.What is the role of DNA in reproduction?

Correct Answer: B

Q25.Which contraceptive method involves altering the hormonal balance to prevent egg release?

Correct Answer: C

Q26.In the context of DNA replication during reproduction, which of the following is a consequence of errors in DNA copying?

Correct Answer: A

Q27.What is the primary role of DNA in the process of reproduction?

Correct Answer: B

Q28.Which part of the flower contains the male germ-cell?

Correct Answer: D

Q29.Which of the following is a method of asexual reproduction in yeast?

Correct Answer: B

Q30.Why is sexual reproduction considered advantageous over asexual reproduction?

Correct Answer: B

Q31.What is the function of the pollen tube during fertilization in plants?