Asexual reproduction/Vegetative propagation Questions in English

(D) Plant viruses can be transmitted through various vegetative propagules used in agriculture.
Tubers,rhizomes,and stem cuttings are all common methods of vegetative propagation.
If the parent plant is infected with a virus,the virus is transmitted to the new plant through these vegetative parts.
Therefore,all the listed options are valid modes of virus transmission.

(C) The total time given is $3$ hours,which is equal to $3 \times 60 = 180$ minutes.
The number of generations $(n)$ is calculated by dividing the total time by the time taken for one division: $n = 180 / 20 = 9$ generations.
The number of bacteria produced after $n$ generations is given by the formula $2^n$.
Therefore,the number of bacteria = $2^9 = 512$.

(B) Bacteria reproduce by binary fission,where one cell divides into two daughter cells in each generation.
Let $n$ be the number of generations.
The number of cells produced after $n$ generations is given by the formula $N = 2^n$,where $N$ is the total number of cells.
Given $N = 1024$,we have $2^n = 1024$.
Since $1024 = 2^{10}$,we get $n = 10$.
Therefore,$10$ generations are required to produce $1024$ cells.

(A) $Plasmodium$ reproduces by multiple fission,not binary fission.
In $Plasmodium$,the parent cell divides into many daughter cells simultaneously.
$Amoeba$,$Euglena$,and $Paramecium$ typically reproduce by binary fission under favorable conditions.

(C) In yeast $(Saccharomyces \text{ } cerevisiae)$, budding is a form of asexual reproduction.
When a bud forms, a primary septum is synthesized to separate the daughter cell (bud) from the parent cell.
This primary septum is primarily composed of chitin, which provides structural integrity during the separation process.
After the primary septum is formed, secondary septa composed of glucans and mannans are deposited on both sides of the primary septum to complete the cell wall formation.

(B) Budding is a form of asexual reproduction observed in yeast ($Saccharomyces$ $cerevisiae$).
During this process,a small outgrowth called a bud is formed on the parent cell.
The nucleus of the parent cell undergoes mitosis and divides into two daughter nuclei.
One of these daughter nuclei migrates into the bud.
Subsequently,the cytoplasm undergoes unequal division,where the bud receives a smaller portion of the cytoplasm compared to the parent cell.
Therefore,the characteristic feature of budding in yeast is the unequal division of the cytoplasm.

(B) $Zoospore$ is a motile,flagellated asexual spore produced by certain algae and fungi.
These spores are formed within a specialized structure called a $Zoosporangium$.
Upon the bursting of the mother cell $(Zoosporangium)$,these zoospores are released into the environment to give rise to new organisms.
Examples include $Ulothrix$ and $Oedogonium$.

(D) Vegetative reproduction is a common method of asexual reproduction in many lower plants and fungi.
$1$. Algae reproduce vegetatively through fragmentation.
$2$. Fungi reproduce vegetatively through fragmentation,budding,or fission.
$3$. Bryophytes (such as mosses) reproduce vegetatively through fragmentation and the formation of specialized structures like gemmae.
Therefore,all the mentioned groups exhibit vegetative reproduction under favourable conditions.

(A) Gemmules are internal asexual reproductive bodies found in all freshwater and some marine sponges.
They are formed as internal buds that help the organism survive during unfavourable environmental conditions.
When conditions become favourable,the gemmules germinate to form new sponges.

(B) Budding is a type of asexual reproduction where a new organism develops from an outgrowth or bud due to cell division at one particular site.
In $Hydra$,the bud develops into a new individual and eventually detaches from the parent body.
In sponges (Porifera),budding is also a common method of asexual reproduction,often involving the formation of internal buds called gemmules or external buds.
Starfish reproduce primarily through fragmentation or sexual reproduction,and tapeworms are hermaphrodites that typically reproduce sexually.
Therefore,$Hydra$ and sponges are the correct organisms that exhibit budding.

(B) $Hydra$ possesses a remarkable power of regeneration,which is the ability to replace lost tissues or regrow entire body parts. If a living $Hydra$ is cut into two or more small fragments,each fragment has the potential to develop into a new,complete individual.

(B) In $Hydra$,asexual reproduction occurs through budding. When multiple buds are formed,they develop in a specific sequence. The oldest bud is located towards the basal or aboral end,while the younger buds are formed progressively towards the oral end. This is because the growth zone is situated near the oral region,and as the body grows,the older buds are pushed towards the aboral region.

(A) $Hydra$ is a freshwater organism that primarily reproduces asexually through a process known as budding. In this process,a small outgrowth called a bud develops on the parent body due to repeated cell division at a specific site. This bud grows,develops tentacles,and eventually detaches from the parent to become a new,independent individual.

(B) When a $Hydra$ is cut into two pieces,it exhibits a high power of regeneration. Each piece regenerates the missing parts based on its original polarity. The basal disc develops towards the lower side,while the mouth,hypostome,and tentacles develop at the upper side of each piece,ensuring the restoration of the complete organism.

(C) 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.
In $Hydra$,the cells divide rapidly at a specific site and develop as an outgrowth called a bud.
These buds develop into tiny individuals and,when fully mature,detach from the parent body to become new independent individuals.
$Amoeba$ and $Paramecium$ typically reproduce by binary fission,while $Plasmodium$ reproduces by multiple fission.

(B) Sweet potato $(Ipomoea \text{ } batatas)$ exhibits vegetative propagation through its roots.
These are known as adventitious roots, which store food and develop adventitious buds.
When these roots are planted in the soil, the adventitious buds sprout to form new plants.
In contrast, potato $(Solanum \text{ } tuberosum)$ uses stem tubers, while ginger $(Zingiber \text{ } officinale)$ and onion $(Allium \text{ } cepa)$ use rhizomes and bulbs (modified stems), respectively.

(A) $Bulbils$ are fleshy vegetative buds that store food and participate in vegetative propagation.
In $Agave$,the $bulbils$ germinate while still attached to the inflorescence,a phenomenon known as $vivipary$.

(A) New banana plants develop from a specialized underground stem modification known as a rhizome.
Specifically,the banana plant reproduces vegetatively through a type of rhizome that grows vertically,often referred to as a rootstock or sucker.
Therefore,the correct option is $A$.

(C) An offset is a short,thick runner that is one internode long.
It is typically found in rosette plants growing at the ground or water level,arising from the axil of a leaf.
Examples include Water Lettuce $(Pistia)$ and Water Hyacinth $(Eichhornia)$.
Therefore,the correct option is $(C)$.

(C) bulbil is a specialized vegetative or floral bud that becomes swollen and fleshy.
It serves as a means of vegetative propagation.
When it detaches from the parent plant,it develops into a new independent plant.
Examples include $Agave$ and $Oxalis$.

(B) In some plants,vegetative propagation is carried out by the production of epiphyllous buds on leaves.
Such leaves are called reproductive leaves. For example,$Bryophyllum$.

(B) The correct answer is $B$.
An $Offset$ is a type of vegetative reproductive structure found in aquatic plants.
It is a lateral branch with a short internode that grows horizontally.
It produces a new tuft of leaves and a cluster of roots at the node,eventually forming a new plant.
$Eichhornia$ $(Water\, hyacinth)$ is a classic example of a plant that reproduces via offsets.

(C) When stem cuttings are planted for vegetative propagation,they lack a developed root system to absorb sufficient water from the soil.
Leaves are the primary sites of transpiration,a process where water is lost as vapor.
By removing some leaves,the total surface area available for transpiration is reduced.
This helps in minimizing water loss,thereby preventing the cutting from wilting or drying out before it can establish a new root system.

(B) In $Bryophyllum$,vegetative propagation occurs through the leaves.
These leaves possess adventitious buds in the notches along the leaf margins.
When these leaf segments come in contact with moist soil,these buds develop into new plantlets.
Therefore,the presence of buds is responsible for the formation of new plants.

(B) Plants that are genetically identical to the parent plant are known as clones.
Vegetative propagation,such as stem cutting,involves mitosis,which ensures that the offspring are genetically identical to the parent plant.
In contrast,seeds are produced through sexual reproduction,which involves meiosis and fertilization,leading to genetic variation in the offspring.
Therefore,plants identical to the mother plant can only be obtained through vegetative propagation methods like stem cutting.

(C) clone refers to a group of morphologically and genetically identical individuals.
Vegetative propagation is a type of asexual reproduction where new plants are produced from vegetative parts of the parent plant,such as corms,bulbs,tubers (e.g.,potato),or runners.
Since this process involves mitosis and no genetic recombination occurs,the offspring are clones of the parent.

(C) is the correct answer. Sowing is the process of planting seeds in the soil,which is a method associated with sexual reproduction,not vegetative propagation. Vegetative propagation involves the formation of new plants from vegetative parts like roots,stems,or leaves without the involvement of seeds.

(C) Genetically identical progeny,also known as clones,are produced through asexual reproduction. In asexual reproduction,a single parent produces offspring without the fusion of gametes or the involvement of meiosis. Since there is no genetic recombination or variation introduced,the offspring are genetically identical to the parent.

(A) Layering is a method of vegetative propagation where a branch of the plant is bent towards the ground and covered with soil to induce root formation.
$Jasmine$ is a classic example of mound layering,where the lower branches are covered with soil to develop adventitious roots.
While other plants can be propagated by cuttings or grafting,layering is specifically and commonly associated with $Jasmine$ in botanical studies.

(C) The correct answer is $(C)$ Walking fern $(Adiantum \, caudatum)$.
In $Adiantum \, caudatum$,the leaf tips develop adventitious buds when they come in contact with the soil.
These buds grow into new plantlets,allowing the plant to propagate vegetatively through its leaf tips.

(C) The correct answer is $C$.
$Bryophyllum$ plants produce adventitious buds on the margins of their leaves.
These buds are known as 'Foliar adventitious buds'.
When these buds detach from the leaf and fall onto the soil,they develop into new individual plants.
This is a specialized form of vegetative propagation.

(A) Vegetative propagation by leaves occurs when adventitious buds develop on the leaf margins or surfaces.
In $Bryophyllum$,the leaf margins possess notches where epiphyllous buds (adventitious buds) develop. When these leaves fall on moist soil,these buds grow into new plantlets.
Similarly,$Kalanchoe$ also reproduces vegetatively through leaf buds.
Therefore,the correct pair is $Bryophyllum$ and $Kalanchoe$.

(A) Parthenogenesis is a form of asexual reproduction where an embryo develops from an unfertilized egg cell.
In this process,the development of an individual occurs from a single gamete without the process of fertilization.
Therefore,it is categorized under asexual reproduction.

(A) Vegetative propagation is a type of asexual reproduction where new plants are formed from vegetative parts of the parent plant.
Since it involves only mitotic cell division,there is no recombination or segregation of genes.
Therefore,the most significant value of vegetative propagation is that it produces a large population of individuals that are genetically identical to the parent,often referred to as clones.

(B) Asexual reproduction is a mode of reproduction where a single parent produces offspring without the involvement of gamete formation or fusion.
This process is primarily observed in lower organisms,such as unicellular organisms (e.g.,$Amoeba$,$Bacteria$) and some simple multicellular animals (e.g.,$Hydra$,$Sponges$).
Therefore,the correct option is $(b)$.

(D) Gemmule formation is a specialized method of asexual reproduction observed in sponges (Porifera).
These are internal buds that act as perennating structures,allowing the organism to survive unfavorable environmental conditions.
When conditions become favorable,the gemmules germinate to form new sponge individuals.
Therefore,it is a type of asexual reproduction.

(B) Genetically identical progeny are produced through asexual reproduction.
In asexual reproduction,a single parent produces offspring that are genetically and morphologically identical to themselves,known as clones.
This process involves mitosis,which ensures that the genetic material is replicated and distributed equally to the daughter cells without the recombination or segregation associated with meiosis.

(A) Vegetative propagation is a type of asexual reproduction in plants where new individuals are produced from vegetative parts like roots,stems,or leaves without the involvement of fertilization or seed formation.
Since vegetative propagation is a form of asexual reproduction,it does not involve the fusion of gametes (fertilization).
Therefore,the correct answer is $A$.

(B) clone is defined as a group of morphologically and genetically identical individuals.
Since asexual reproduction involves only a single parent and does not involve meiosis or fertilization,the offspring produced are genetically identical to the parent.
Because they are genetically identical,they are essentially homozygotes for all their alleles relative to the parent.
Therefore,a clone is a homozygote produced by asexual means.

(A) Parthenogenesis is a form of asexual reproduction where an embryo develops from an unfertilized egg.
In $Apis$ $mellifera$ (Honey bee),the queen lays unfertilized eggs that develop into haploid males,known as drones,through the process of parthenogenesis.
Therefore,the correct option is $A$.

(B) Vegetative propagation is an asexual method of reproduction in plants.
Since it involves mitosis,the offspring produced are genetically identical to the parent plant.
This ensures that the specific genetic traits (desirable characteristics) of the parent plant are maintained in the progeny without any variation.
In contrast,sexual reproduction (via seeds) involves meiosis and fertilization,which introduce genetic recombination and variation.

(B) Multicellular fungi,filamentous algae,and the protonema of mosses all share the ability to reproduce through fragmentation.
In fragmentation,the organism breaks into smaller pieces (fragments),and each fragment develops into a new individual.
This is a common method of asexual reproduction in these specific groups of organisms.

(A) Parthenogenesis is a form of asexual reproduction in which an embryo develops from an unfertilized egg.
It is commonly observed in organisms like honeybees,rotifers,and some lizards.
Parthenocarpy refers to the development of fruit without fertilization in plants.
Apomixis is a type of asexual reproduction that mimics sexual reproduction in plants.
Amphimixis refers to the fusion of male and female gametes.

(A) genetic clone refers to an organism or cell that is genetically identical to its parent.
In the context of plants,clones are produced through asexual reproduction (such as vegetative propagation,tissue culture,or apomixis).
Since asexual reproduction involves only mitosis and no fusion of gametes,the offspring are genetically identical to the parent,making them clones.
Therefore,the correct option is $A$.

(A) Vegetative propagation through leaves occurs when adventitious buds develop on the leaf margins or surfaces.
In $Bryophyllum$ and $Kalanchoe$,the leaf margins possess notches where adventitious buds are formed.
When these leaves fall on moist soil,these buds develop into new plantlets.
Therefore,the correct pair is $Bryophyllum$ and $Kalanchoe$.

(NONE) In the given options,the pair 'Water hyacinth - Offset' is correct as it reproduces vegetatively through offsets. 'Grass - Runner' is correct as it spreads via runners. 'Bryophyllum - Leaf buds' is correct as it produces adventitious buds on leaves. However,'Agave - Bulbils' is the correct biological association,but in the context of vegetative propagation types,the option 'Agave - Bulbils' is often contrasted with other vegetative structures. Wait,checking the options: 'Agave - Bulbils' is actually correct. Let's re-evaluate: 'Grass - Runner' is correct. 'Water hyacinth - Offset' is correct. 'Bryophyllum - Leaf buds' is correct. Actually,all these are correct examples of vegetative propagation. If the question implies an error,perhaps 'Agave' is sometimes associated with 'Bulbils' but the question might be looking for a specific mismatch. Given the standard $NCERT$ context,all these are correct. However,if forced to choose,'Agave' is a bulb-like structure but specifically 'Bulbils'. Actually,all are correct. Let's assume the question intended to test the specific vegetative structure. All options provided are scientifically correct examples of vegetative propagation.

(A) In $Pistia$ (water lettuce) and $Eichhornia$ (water hyacinth),vegetative propagation takes place through a specialized structure called an $Offset$.
An $Offset$ is a lateral branch with a short internode,and each node bears a rosette of leaves and a tuft of roots.
This structure allows the plant to spread rapidly over the surface of the water.

(B) Vegetative propagation is a form of asexual reproduction in plants where new individuals develop from vegetative parts like roots,stems,or leaves.
In $Bryophyllum$ (commonly known as $Patharchatta$ or $Bryophyllum$) and $Kalanchoe$,the leaves possess adventitious buds in their marginal notches.
When these leaves fall on moist soil,these buds develop into new plantlets,which eventually grow into independent plants.
Therefore,the correct pair is $Bryophyllum$ and $Kalanchoe$.

(B) In the human body, $Plasmodium$ undergoes asexual reproduction through a process called $schizogony$, which is a form of $multiple \text{ } fission$.
When the sporozoites enter the human liver cells, they multiply by multiple fission to produce merozoites.
Subsequently, these merozoites infect red blood cells $(RBCs)$, where they continue to multiply via multiple fission, eventually causing the rupture of $RBCs$ and the release of toxins like $haemozoin$.

(B) The walking fern,scientifically known as $Adiantum \ caudatum$,is a type of fern that propagates vegetatively through its leaf tips. When the tip of the leaf touches the soil,it develops adventitious roots and a new plantlet,allowing the plant to 'walk' or spread across the ground.