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Karnataka 2nd PUC Biology Question Bank Chapter 1 Reproduction
2nd PUC Biology Reproduction One Mark Questions and Answers
Define the term reproduction.
It is a biological process in which an organism gives rise to young ones similar to itself.
What is binary fission?
This is a type of asexual reproduction which occurs in single celled organisms, where a cell divides into two halves and each rapidly grows into an adult.
Name the type of reproduction structure that occurs in yeast.
Name the type of reproduction structures produced by fungi.
Which are the 2 main Pre-fertilization events?
Gametogenesis and gamete transfer.
What are hermaphrodites?
The animals in which both the sex organs are present in the same body, are called hermaphrodites.
The fusion of gametes which results the formation of zygote is called syngamy.
Define vegetative propagation.
Vegetative propagation is the mode of regeneration of new plants from a portion of the vegetative organs.
What are gemmules?
Internal asexual reproductive units or buds in sponges are called gemmules.
Parthenogenesis is the development of an unfertilized ovum into a fully formed organism.
Why is reproduction essential for organisms?
Reproduction is necessary for the continuation of life and to compensate for the loss of life due to death of a particular organism.
What is senescent phase?
After reproductive maturity, all organisms enter into a senescent phase. This phase is characterised by gradual decrease in functional activities and cellular breakdown leading to the death of the organism.
Why offsprings of oviparous animals are at a greater risk?
The offsprings of oviparous animals are at the greater risk because of greater predation by different types of animals.
Why are the offsprings formed by asexual reproduction referred to as clones?
The offsprings formed by asexual reproduction are genetically identical to each other, hence are called clones.
What is a clone?
Morphologically and genetically similar individuals produced as a result of asexual reproduction are clones.
What are vegetative propagules?
The units of vegetative propagation such as tuber, bulb, rhizome etc are called vegetative propagules.
Name the phase all organisms have to pass through before they can reproduce sexually.
Name a unicellular fungi which reproduces asexually by budding?
Name a multicellular invertebrate which reproduces asexually by budding.
Name the artificial means of vegetative reproduction.
The artificial means of vegetative reproduction are cuttings, layering, grafting and micro propagation.
Name the asexual reproductive structures of Hydra and Penicillium.
2nd PUC Biology Reproduction Two Marks Questions and Answers
Diagrammatically represent the asexual reproduction in Amoeba.
Which is a better mode of reproduction:- sexual or asexual? Why?
Sexual reproduction is the better method of reproduction, because it brings genetic recombination and variations and contributes to the evolution of the species (more complex and advanced). The organism’s habitat, its internal physiology and several other factors collectively decide how it reproduces.
Offsprings formed due to sexual reproduction have better chances of survival, why? Is this statement always true?
Sexual reproduction combines the characters of two parents and introduces variations which make the offsprings better equipped for the struggle of existence. Yes.
How does the progeny formed from asexual reproduction differ from those formed by sexual reproduction?
The progeny formed from asexual reproduction is the product of single parent and does not have genetic variations, whereas the offsprings formed by sexual reproduction show changes.
Distinguish between asexual and sexual reproduction. Why is vegetative reproduction also considered as a type of asexual reproduction?
Asexual Reproduction: The production of offsprings by a single parent without the formation and fusion of gametes is called asexual reproduction. It is also known as agamogenesis or agamogeny.
Sexual Reproduction: Sexual reproduction involves formation of the male and female gametes either by the same individual or by different individuals of the opposite sex. These gametes fuse to form the zygote which develops to form the new organism.
Vegetative reproduction involves single parent and the offsprings formed by vegetative reproduction are genetically identical hence it is considered as a type of asexual reproduction.
What is vegetative propagation? Give two suitable examples.
The process of multiplication in which portions or fragments of the plant body function as propagule and develop into new individuals is called vegetative propagation, e.g., potato, Bryophyllum.
Higher organisms have resorted to sexual reproduction inspite of its complexity, why?
Higher organisms have resorted to sexual reproduction inspite of its complexity because sexual reproduction induces genetic variability (adaptations) for the survival of the race and for better adaptation of the existing environmental conditions.
Explain why meiosis and gametogenesis are always interlinked?
The process of gametogenesis involves meiosis to produce haploid gametes. Therefore, meiosis and gametogenesis are always interlinked.
Define external fertilization. Mention its disadvantages.
When the fusion of gametes occurs outside the body of the organism in the external medium it is called external fertilization
Disadvantages: Many of the gametes fail to fuse, hence the organisms exhibiting external fertilization have to produce a large number of gametes (wastage of gametes).
Differentiate between gametogenesis from embryogenesis.
- It is the process by which male and female gametes are formed.
- It involves meiosis.
- It is the process of development of an embryo from a zygote.
- It involves mitosis.
Briefly describe the post fertilization changes in a flower.
After fertilization sepals, petals and stamens usually wither and fall off. The zygote develops into an embryo, the ovules develop into seeds and ovary matures into a fruit. The ovary wall is transformed into a protective layer called pericarp.
Differentiate between a staminate and a pistillate flower. Give the term for this condition of flower.
The unisexual male flower is called staminate, which bears only stamen.
The unisexual female flower is called pistillate, which bears only pistil gynoecium.
Heterothallic or dioecious are the terms used to describe this condition.
Explain parthenogenesis with examples.
The process of development of new organism from female gamete without fertilization is called parthenogenesis. Example, Rotifers, honeybees, turkey (birds).
What is fission? Name the types of fission.
Fission is a type of asexual reproduction in which the unicellular parental organisms divide into two or more small daughter organisms.
It is of two types:
(a) Binary fission
(b) Multiple fission.
Differentiate between the following:
(a) Zoospore and zygote
|It is a haploid and motile spore formed during asexual reproduction in lower plants and fungi.||Zygote is a diploid and non motile cell formed due to the fusion of male and female gametes in sexual reproduction.|
(b) Syngamy and fertilisation
|It is the actual fusion of male and female gametes||It includes all the associated events that lead to syngamy.|
Differentiate between a zoospore and a zygote.
A zoospore is usually flagellated, haploid or diploid spore formed inside a zoosporangium. The zygote, on the other hand is always diploid and formed as a result of fusion of gametes. The zygote is usually nonflagellated.
Define ‘oestrus’ and ‘menstrual’ cycles.
Non-primates like cows, sheep etc., show certain cyclic changes during reproduction called oestrus cycle while in primates like apes and humans, the cycle is referred to as menstrual cycle.
Mention the different stages of sexual reproduction.
The different stages in sexual reproduction include:
- Pre-fertilization events.
- Post – fertilization events.
Differentiate between oviparous and viviparous animals with a suitable example for each.
Egg laying animals are callled oviparous animals,
Animals give birth to young ones.
e.g.: Majority of mammals including human beings.
What is asexual reproduction? Mention the type of asexual reproduction in amoeba and in sponge.
The reproduction in which an offspring is produced by a single parent with or without the involvement of gamete formation is asexual reproduction.
In Amoeba -binary fission
In Sponge – gemmule formation.
Differentiate between seasonal breeders and continuous breeders.
Many animals living in the wild which exhibit their reproductive phase only during favourable season are called seasonal breeders.
Many other animals are reproductively active throughout their reproductive phase, hence they are called continuous breeders.
2nd PUC Biology Reproduction Three Marks Questions and Answers
Differentiate between binary and multiple fission.
Differentiate between a zoospore and a zygote.
- It is produced during asexual reproduction
- It is formed by mitotic division and is haploid.
- It bears flagella and is motile.
- It directly produces a new organism.
- It is formed during sexual reproduction.
- It is formed by the fusion of gametes and is diploid.
- It is without flagella and is non-motile.
- It may produce new organism directly or after meiosis.
1. Juvenile phase,
2. Reproductive phase,
3. Senescent phase.
1. Juvenile phase: The phase of growth in the organisms before reproductive maturity,
2. Reproductive phase: The phase in which an organism attains reproductive maturity, i.e., development of sex organs takes place.
3. Senescent phase: The phase between reproductive maturity and death.
List the differences between external fertilisation and internal fertilisation?
|External fertilisation||Internal fertilisation|
|When fusion of gametes (syngamy) occurs outside the body of the organism, it is called external fertilisation.||When fusion of gametes (syngamy) occurs inside the body of the organism, it is called internal fertilisation.|
|A large number of gametes are released in the surrounding medium by such animals e.g., bony fishes, amphibians, etc.||The number of ova produced is less, but a large number of male gametes are formed, as many of them fail to reach the ova. e.g., birds, mammals, earthworm, etc.|
Name the following :
1. Asexual reproductive structures of Hydra.
2. Vegetative propagules of Agave.
3. The plant that flowers once in twelve years.
What kind of reproduction is seen in following organisms? Penicillium, chlamydomonas and sponges.
(c) Gemmule formation
2nd PUC Biology Reproduction Five Marks Questions and Answers
Describe the post-fertilisation changes in a flower.
The post-fertilisation changes that take place in a flower are as follows:
- The formation of zygote (inside ovule) which later develops into an embryo and primary endosperm cell which develops into endosperm (providing nourishment to the growing embryo) takes place.
- While the sepals, petals and stamens are shed, the pistil remains intact.
- The fertilised ovule develops into seeds.
- The ovary matures into a fruit that later develops a thick, protective wall called pericarp.
- Seeds after dispersal germinate under favourable conditions and develop into a new plant.
Give an account of pre-fertilisation events?
Pre-fertilization events: These are the events which occur prior to the fusion of gametes. Pre-fertilization events include gametogenesis and gamete transfer.
Gametogenesis: Gametogenesis is the process by which male and female sex cells or gametes are formed. Gametes are haploid cells. In.some algae, the two gametes are similar in appearance (morphology) and are called homogametes (=isogametes), such gametes cannot be distinguished into male and female gametes. However, in majority of sexually reproducing organisms the gametes formed are of two morphologically distinct types, called heterogemetes. In such organisms, the male gamete is called the antherozoid or sperm and the female gamete is called the egg or ovum.
Gamete transfer: When the male and female gametes are formed, they are physically brought together so as to facilitate their fusion. In most of the organisms, the male gamete is motile, whereas the female gamete is non-motile or stationary.
Distinguish between asexual and sexual reproduction. Why is vegetative reproduction also considered as asexual.
|It involves participation of a single individual||It involves two separate parents|
|No sex organs are formed||Sex organs are formed|
|No cell division like meiosis.||It involves meiosis during gamete formation|
|No gamete fusion, thus no formation of zygote.||Male and female gametes fuse to form Zygote.|
|Thus offspring are similar to parents due to non fusion of gametes.||The offspring are genetically variants, because of fusion of gametes.|
|The process is quick, in the absence of processes like fertilization and embrogenesis||The process takes a long duration, because it involves fertilization, and embryogenesis.|