Reproduction

Types of reproduction:

1. the offspring of asexual reproduction describes
   1. They result without the fusion of gametes.
      1. Offspring of asexual reproduction result from only one parent, so they do not require the fusion of two parent gametes.
      2. Offspring of asexual reproduction are identical to their parents, since they only have a single source of genetic information
      3. Asexually reproducing organisms develop very quickly compared to offspring of sexual reproduction.
   2. Which of the following answer choices best describes the image shown below?

1. It depicts asexual reproduction occurring through binary fission, a process that does not lead to genetic variation.
   1. This organism lacks a nucleus and membrane-bound organelles, so it must be a prokaryote. Prokaryotes reproduce through asexual reproduction, specifically binary fission, resulting in two identical daughter cells.
2. A species of shark reproduces sexually in the wild, but females of this species can reproduce asexually in captivity. What is one disadvantage of asexual reproduction?
   1. Decreased genetic diversity within the species
      1. Asexual reproduction reduces genetic diversity because all of the offspring are identical to the parent.
3. Which of the following statements is true for asexual reproduction?
   1. Mode of reproduction for Escherichia coli, a prokaryotic organism
      1. Prokaryotes, like the bacteria Escherichia coli, all undergo asexual reproduction in order to reproduce.
   2. Can occur in animals through fragmentation
      1. In fragmentation, organisms break into two or more fragments that develop into a new individual. This can occur in animals like corals, sponges, and starfishes.
4. In a species of yeast, a new individual develops as an outgrowth on a parent, which then separates from the parent once it has matured. What type of reproduction is this?
   1. Budding
      1. The yeast is undergoing the process of budding. The outgrowth that forms is a “bud,” which grows attached to the parent yeast before breaking off and developing further.
5. In a species of yeast, a new individual develops as an outgrowth on a parent, which then separates from the parent once it has matured. What type of reproduction is this?
   1. Budding
      1. The yeast is undergoing the process of budding. The outgrowth that forms is a “bud,” which grows attached to the parent yeast before breaking off and developing further.
6. Which statement applies to all forms of sexual reproduction?
   1. Offspring receive genetic material from two gametes.
      1. In sexual reproduction, offspring receive DNA from two parents via gametes. The gametes fuse together during fertilization, forming a zygote, which will develop into an embryo.
7. Which of the following is true of binary fission?
   1. It produces two identical daughter cells.
      1. Binary fission is asexual, so the offspring are identical to the parent cell.
8. Which of the following statements is true for sexual reproduction?
   1. Sperm fertilizes egg
      1. In order to form a unique zygote, a sperm cell must fertilize and fuse its unique genetic information with the unique genetic information of an egg cell, resulting in a genetically unique offspring.
   2. Provides genetic variation, but time-consuming
      1. Sexual reproduction results in the fusion of a genetically unique gametes, so the offspring will be different from the parents. However, this often involves finding a mate and long periods of embryonic development.
9. Female New Zealand mud snails are able to produce viable offspring that develop into mature adults from unfertilized eggs. What type of reproduction is this?
   1. Parthenogenesis
      1. Parthenogenesis occurs when the unfertilized egg of a female develops into a mature adult without any contribution from a male of that species.

Types of asexual reproduction:

1. Leishmania, the protozoan species that causes Kala-azar is named after Dr. Leishman who discovered it from a British soldier’s spleen in 1903 in Dumdum, near Kolkata. This is why Kala-azar is also called Dumdum fever. During Kala-azar infection, Leishmania reproduces through binary fission inside the body of the patient. Which of the following statements about binary fission is true?
   1. Binary fission produces two new organisms.
      1. In binary fission, a unicellular organism (a cell) divides to form two unicellular organisms (two cells).
2. India missed two consecutive deadlines, one in 2015 and another in 2017 to eliminate the life-threatening disease Kala-azar. Serious efforts are being made by the government to eradicate this disease. Leishmania, the protozoan that causes this disease, reproduces through binary fission. Which of the following statements about binary fission are true?
   1. Binary fission is observed in unicellular organisms.
      1. Unicellular organisms like Amoeba and Leishmania reproduce through binary fission.
   2. Binary fission in amoeba can happen in any plane.
      1. In unicellular organisms like Amoeba that have no body organisation, binary fission can happen in any plane.
   3. Binary fission is simply cell division.
      1. Binary fission is simply division of a cell (a unicellular organism) into two new daughter cells (two unicellular organisms).
3. The organism that causes Kala-azar reproduces through binary fission whereas the organism that causes malaria reproduces through multiple fission. Categorize the following statements as applicable to binary fission or multiple fission or both.

	Multiple fission	Binary fission
Many offsprings	Yes
Found in Leishmania		Yes
Found in Plasmodium	Yes
Found in Amoeba		Yes

1. In which of the following aspects does multiple fission differs from binary fission
   1. Number of offsprings produced.
      1. Multiple fission produces many offsprings whereas binary fission produces only two
   2. Multiple fission happens in Plasmodium whereas binary fission happens in Leishmania.
      1. Plasmodium, the protozoan that causes malaria reproduces through multiple fission. Leishmania causes Kala-azar and it reproduces through binary fission.
2. If you ever saw a green slimy layer on a pond’s water surface, it was largely due to the growth of filamentous green alga called Spirogyra. They reproduce fast making the pond surface look green and unattractive. Through which mode of asexual reproduction does spirogyra reproduce?
   1. Fragmentation
      1. Spirogyra reproduces through fragmentation once it matures and achieves considerable length.
3. When a hydra is cut into two halves, each half develops into a new hydra. What is such capacity to develop into a new organism from cut body part called?
   1. Regeneration
      1. Regeneration is the capacity of an organism as a result of which it’s cut body part develops into a new organism.
4. Spores are reproductive cells capable of giving rise to new organisms under favorable conditions. Organisms like bread mold (Rhizopus) form spores in large numbers. Which of the following statements are true about reproduction through spore formation in Rhizopus?
   1. Spores are covered by thick walls
      1. Spores are covered by thick walls that protects them from getting destroyed in harsh environmental conditions.
   2. The offsprings that germinate from spores have DNA identical to that of their parent.
      1. Since spore formation is an asexual process, the offsprings that germinate from spores have DNA identical to that of their parent.
5. In the image below, two outgrowths can be seen on the body of a Hydra. When these outgrowths will become mature, they will detach from the parent and develop into a new organismChoose statements that correctly apply to the figure

1. The outgrowths form as a result of repeated cell division.
   1. Repeated cell division at specific site on Hydra’s body leads to the formation of an outgrowth
2. The outgrowths are called bud.
   1. The outgrowths that develop on Hydra’s body are called buds and the reproductive process is called budding.
3. A student studying regeneration in laboratory removes the head of a Planarian (plural-Planaria) from its body. What will happen to the two body fragments of the Planarian?
   1. Both body fragments will develop into new Planarian worm
4. What happens when a Planarian (plural-Planaria) is cut into many fragments?
   1. All fragments regenerate into new organisms.
      1. Cells that cause regeneration are present all over the body of a Planarian. So when a Planarian is cut into many fragments, all fragments regenerate into new organisms.
5. Spores are reproductive cells capable of giving rise to new organisms under favorable conditions. Organisms like bread mold (Rhizopus) form spores in large numbers. Which of the following statements are true about reproduction through spore formation in Rhizopus?
   1. Spores are covered by thick walls.
      1. Spores are covered by thick walls that protects them from getting destroyed in harsh environmental conditions.
   2. The offspring’s that germinate from spores have DNA identical to that of their parent.
      1. Since spore formation is an asexual process, the offsprings that germinate from spores have DNA identical to that of their parent.
6. When a hydra is cut into two halves, each half develops into a new hydra. What is such capacity to develop into a new organism from cut body part called?
   1. Regeneration
      1. Regeneration is the capacity of an organism as a result of which it’s cut body part develops into a new organism.
7. In budding, a new organism grows on the parent organism and remains attached as it grows. Once fully grown, it detaches and becomes an independent organism.Which of the following statements are true about budding?
   1. Budding is seen in Hydra.
      1. Hydra reproduces through budding.
   2. Offsprings produced through budding are genetically identical to parents.
      1. Budding is an asexual form of reproduction in which only one parent is involved and there is no mixing of genes. Thus, offsprings produced through budding are genetically identical to their parents.
   3. Budding involves repeated cell division.
      1. Repeated cell division lead to the outgrowth that turns into a bud. The bud eventually turns into a new organism through more cell division cycles.

Vegetative propagation:

1. Which of the following plants have lost the capacity to produce seeds and can only be grown through vegetative propagation?
   1. Jasmine
      1. Jasmine plants have lost the capacity to produce seeds and can be grown only through vegetative propagation.
   2. Rose
      1. Rose plants have lost the capacity to produce seeds and can be grown only through vegetative propagation.
2. Although plants like banana and rose have lost the capacity to produce seeds, they are still grown widely. This is possible through vegetative propagation that enables reproduction from parts other than seeds. What are the other advantages of vegetative propagation?
   1. Plants raised through vegetative propagation can bear fruits earlier than those raised from seeds.
      1. Vegetative propagation is faster than sexual reproduction because the time required for flowering, pollination, and seed formation is eliminated in vegetative propagation.
   2. Plants raised using vegetative propagation are genetically identical to the parent plant.
      1. Plants raised using vegetative propagation are genetically identical to each other and to the parent plant. This helps the farmer in maintaining the unique taste and flavour of a particular fruit or crop variety.
3. Imagine you are eating a very tasty mango and now you want to grow the same variety of mango in your backyard. Which of the following would be the best way to grow it?
   1. Bringing a layered stem cutting of the same mango variety from a nursery and planting it in the backyard.
      1. The mango tree grown from a layered stem cutting will produce exactly the same variety of mango as the parent plant because there is no mixing of DNA in this process of reproduction.
4. Rohit planted a layered stem cutting of his prized Alphonso mango tree instead of planting its seed. What features would he observe in the new mango tree?
   1. Same taste and flavour of fruit
      1. Planting a layered stem cutting does not lead to mixing of DNA. So, the new plant will produce the same variety of mango.
   2. Same DNA as the parent plant
      1. Planting a layered stem cutting does not involve mixing of DNA because there is no formation and fusion of gametes. So, the new plant will have the same DNA as the parent plant.
5. Vegetative propagation refers to the growth of new plants from vegetative parts of the parent plant. Which of the following can be called vegetative propagation?
   1. Growing a new rose plant from a stem cutting
      1. The stem is a vegetative part of the plant and therefore, the growth of a new plant from a stem cutting is a form of vegetative propagation.
   2. Growing grapes through grafting technique
      1. Grafting is done on the stem which is a vegetative part. Thus, growing grapes through grafting technique is a form of vegetative propagation.
   3. Growing ornamental plants in a tissue culture laboratory
      1. Shoot tips are vegetative parts used for tissue culture. Therefore, growing ornamental plants in a tissue culture laboratory is vegetative propagation.
6. Which of the following is an example of natural vegetative propagation?
   1. Germination of Bryophyllum from buds
      1. Buds in bryophyllum appear on leaf notches and give rise to new plants on their own. Therefore, it is a natural mode of vegetative propagation.
7. About 1000 varieties of mango are grown commercially in India. Farmers are able to maintain the unique taste and flavor of each variety through vegetative propagation. What other advantages does vegetative propagation offer?
   1. Early fruiting of crops
      1. Plants raised through vegetative propagation bear fruits earlier than those raised from seeds.
   2. Growing plants that have lost the capacity to produce seeds
      1. Vegetative propagation is helpful in growing plants that have lost the capacity to produce seeds. For ex- Banana.

Sexual and asexual reproduction:

1. Sexual reproduction in humans involves the fusion of male and female gametes – the sperm and ovum respectively. What are the characteristics of sexual reproduction in humans?
   1. Two different parents are needed for sexual reproduction in humans.
      1. Sexual reproduction involves fusion of male and female gamete from two different parents.
   2. Sexual reproduction helps in evolution.
      1. Genetic variations arise in offspring produced through sexual reproduction. These variations help the species evolve with the environment.
2. Categorize the following features as advantages of sexual or asexual reproduction.

	Sexual	Asexual
Produces genetically identical offspring	No	Yes
Is faster	No	Yes
Leads to genetic variation	Yes	No
Promotes evolution	Yes	No

1. Although sexual reproduction involves the fusion of two cells, the amount of DNA in the resultant zygote is the same as that in any non-germ line cell. Additionally, the zygote DNA is not identical to that of the parents. How does this happen?
   1. Mixing of DNA from two different gametes leads to variation.
      1. The zygote is formed by the fusion of two cells carrying different sets of DNA. Therefore, the new individual will have a slightly different genetic makeup than either parent.
   2. Both the sperm and the egg cell contain half the amount of DNA that other cells have.
      1. Meiotic division results in germ cells with half the amount of DNA as their parent cells. When they fuse, the zygote receives two halves, or one whole set of DNA.
2. Choose the statements that correctly differentiate sexual reproduction from asexual reproduction.
   1. Sexual reproduction results in more genetic variation than asexual reproduction.
      1. Variations in the DNA can be produced through errors in DNA copying mechanisms. However, sexual reproduction involves the mixing of DNA from two gametes, which increases variation.
3. Which of the following statements about sexual reproduction are true?
   1. Germ cells are produced by meiosis.
      1. Meiosis ensures that germ cells each carry only half the amount of DNA as other cells. When two germ cells are combined, the resulting new individual will have a full set of chromosomes.
   2. Sexual reproduction leads to variations in the genetic material of offsprings.
      1. Offsprings produced through sexual reproduction have DNA patterns slightly different from their parents, a phenomenon also known as variation.
4. In a pond, there are 50 asexually reproducing frogs. Each frog produces one offspring per year. Which of the following statements will be true at the end of a year?
   1. The pond will have 50 baby frogs, genetically identically to their parents.
      1. The offsprings produced through asexual reproduction are genetically identical to their parents.
5. In which of the following aspects does sexual reproduction offer an advantage over asexual reproduction?
   1. Chances of long-term survival.
      1. Sexual reproduction increases the chances of long-term survival of a population by promoting its evolution with the changing environment.
   2. Genetic diversity
      1. Sexual reproduction promotes genetic diversity as the fusion of gametes results in DNA that is slightly different from that of either parent.
6. Sexual reproduction involves the fusion of two parental gametes to produce a zygote. What is resulting DNA composition in the offspring?
   1. The offspring will have the same amount of DNA as each of the parents.
      1. Gametes have half the amount of DNA as other cell types. The offspring arises from the fusion of these gametes. So, it will have two halves, or, one full set of genetic material, similar to each parent.

Haploid versus diploid:

1. The human body has several types of cells, some of which have half the number of chromosomes as the others. Which of the following are haploid in nature?
   1. Sperm cell
      1. Sperm cells, like all gametes, are haploid. This ensures that the fusion of two haploid gametes produces a diploid zygote, which later develops into a human being.
   2. Egg cell
      1. Egg cells, like all gametes, are haploid. This ensures that the fusion of two haploid gametes produces a diploid zygote, which later develops into a human being.
2. The image below is an illustration of a diploid gamete mother cell, with chromosomes 1 and 2What would the haploid gamete cell look like?

1. Haploid cells have one set of each chromosome in the parent cell. This cell has one set each of chromosomes 1 and 2.

1. Haploid (n) organisms, including some fungi and algae, reproduce sexually through the fusion of two specialised structures known as hyphae. If the hyphae are produced by mitotic division of haploid ‘parent’ cells, how many chromosome sets would each structure have?
   1. n
      1. Mitotic division produces daughter cells with the same number of chromosomes as the ‘parent’ cell. Therefore, the hyphae will be haploid (n), like its parent body.
2. If each gamete of the fern, Ophioglossum reticulatum, has 720 chromosomes, how many chromosomes would its meiocytes have?
   1. 1440
      1. Meiocytes are diploid gamete mother cells that divide meiotically to give rise to haploid gametes. Their chromosome number will be twice that of gametes – in this case, 1440
3. Flowers are the sites of sexual reproduction in some plants. The image below depicts the cross-section of a flower. Which of these structures contain haploid cells?
   1. Pollen grain
      1. Pollen grains contain haploid male gametophytes that fuse with female gametophytes during fertilisation.
   2. Ovule
      1. Ovules contain haploid female gametophytes that fuse with male gametophytes during fertilisation.

1. The image below is an illustration of a haploid gamete cell, with one copy each of chromosomes  1,2and3. What would the diploid gamete mother cell look like?

1. Diploid cells have two sets of each chromosome. This cell has two sets of chromosomes 1, 2 and 3

1. Sexual reproduction in some fungi and algae, involves the fusion of specialized structures known as hyphae. This results in the formation of a diploid (2n) zygote, which then undergoes meiotic division to form spores. How many chromosome sets would each spore have?
   1. n
      1. Meiotic division reduces chromosome number by half. Therefore, the spores will have 2n/2 = n chromosome sets.

Sexual reproduction in flowering plants:

Microsporogenesis:

1. Each microsporangium of a bilobed, dithecous anther has 20 microspore, or pollen mother cells. What is the maximum number of microspores this anther can produce?
   1. 320
2. Each microsporangium of a bilobed, dithecous anther has 100 microspore, or pollen mother cells. What is the maximum number of microspores this anther can produce?
   1. 1600
3. The seasonal release of pollen from flowers can cause allergies for some people at that time. The allergies are seasonal because certain processes need to occur before the anther can release pollen grains from within the microsporangia. Which of the following processes need to occur for the release of pollen?
   1. Microspore tetrads should dissociate.
      1. The tetrads dissociate into individual cells that develop into pollen grains.
   2. The anther should undergo dehiscence.
      1. Dehiscence is the process that forces the anther to burst open, leading to the release of pollen.
4. A rare mutation in a plant causes it to produce incompletely developed anthers that cannot produce pollen. This is because the microsporangia plant lack a certain structure which normally contains pollen mother cells (PMCs). Which of the following structures is likely to be missing in the microsporangium of this plant?
   1. Sporogenous tissue
      1. The cells of the sporogenous tissue can give rise to pollen cells, and are so known as pollen mother cells. The absence of this tissue would explain why the plant does not have PMCs.
5. A pollen mother cell (PMC) divides to give rise to microspores. If each microspore has 24 chromosomes, how many did the PMC contain?
   1. 48
6. A pollen mother cell (PMC) divides to give rise to microspores. If each microspore has 12 chromosomes, how many did the PMC contain?
   1. 24
7. The anther on a flower fails to undergo dehiscence. Which of the following events would occur as a result of this failure?
   1. Pollen grains will not be released.
      1. Dehiscence results in the bursting open of the mature anther, and the subsequent release of pollen grains. Failure of dehiscence will prevent release of pollen.
8. Rohan wants to study pollen mother cells (PMCs). He extracts the anthers from a few flowers, and isolates the microsporangia from them. However, he is unsure of which part of the microsporangium he should examine to study PMCs. Which of the following structures should Rohan examine to find PMCs?
   1. Sporogenous tissue
      1. The cells of the sporogenous tissue can give rise to pollen cells, and are so known as pollen mother cells. Rohan should examine this tissue.

Features of pollen grains:

1. In more than half of angiosperms, pollen grains are shed at the 2-cell stage. In the remaining angiosperms, pollen is shed at the 333-cell stage. How does the 2-cell stage give rise to the 3-cell stage?
   1. The generative cell divides mitotically to produce 2 gametes
      1. The generative cell gives rise to 2 gametes which, along with the vegetative cell, make up the 3-cell stage.
2. The viability of pollen grains varies considerably between different species of plants. A farmer wants to send some pollen to a friend in another country. This transportation will take a month to complete. Which of the following plant species would provide the most viable pollen for this journey?
   1. Solanaceae pollen can remain viable for months, so this plant would be a good choice for the journey.
   2. Rosaceae pollen can remain viable for months, so this plant would be a good choice for the journey.
3. Scientists discover a mutant plant that produces defective sporopollenin, which degrades very easily. Which of the following characteristics are the scientists likely to see in the pollen grains of this plant?
   1. They are very fragile.
      1. Sporopollenin protects pollen grains from harsh environmental conditions. The mutant pollen grains will not have this protection, and so will be fragile.
4. Banu collects a few pollen grains from a pea plant and studies them under the microscope. She notices that there are 2 cells (vegetative and generative) within each grain. Which of the following observations will Banu be likely to make about the structure of these pollen grains?
   1. The pollen grain is surrounded by a plasma membrane.
      1. Aside from two outer walls, Banu will also see a plasma membrane surrounding each pollen grain.
   2. The generative cell is spindle-shaped.
      1. Banu will see that the smaller, generative cell is spindle-shaped and lies within the vegetative cell.
5. Angiosperms shed their pollen grains at either the 2- or 3-cell stages. Which of the following statements about the 3-cell stage is true?
   1. This stage occurs after the generative cell undergoes mitosis.
      1. The generative cell divides mitotically to give rise to 2 gametes which, together with the vegetative cell, form the 3-cell stage.
6. A farmer harvests pollen from 3 different plant species – rice, Leguminosae, and Rosaceae. He intends to use this pollen for fertilizing other plants of the same respective species. Since the viability of pollen varies considerably between different species of plants, he needs to complete the fertilization process within a certain time period. Which of the plant species will he need to fertilize first?
   1. Rice
      1. Rice pollen only remains viable for 30 minutes. The farmer should use this pollen for fertilization first.
7. Scientists discover a mutant plant that produces defective sporopollenin, which degrades very easily. Which of the following characteristics are the scientists likely to see in the pollen grains of this plant?
   1. They are viable for very short periods of time.
      1. Pollen grains without sporopollenin will be vulnerable to degradation by enzymes, high temperatures, etc. This means that they will only be viable for short periods of time.
8. Farhan collects a few pollen grains from a pea plant and studies them under the microscope. He notices that there are 2 cells (vegetative and generative) within each grain. Which of the following observations will Farhan be likely to make about the structure of these pollen grains?
   1. The generative cell lies within the vegetative cell.
      1. Farhan will observe that the generative cell lies within the cytoplasm of the larger vegetative cell.
   2. Each cell has a nucleus.
      1. Farhan will observe a small nucleus within the generative cell, and a large, irregularly shaped nucleus within the vegetative cell.

Megasporogenesis and the embryo sac:

1. The development of a mature embryo sac from a functional megaspore occurs through a series of events. Which of the following steps occur in the functional megaspore during this process?
   1. 3 sequential mitotic nuclear divisions.
      1. 3 sequential, free nuclear mitotic divisions occur in the functional megaspore to form the 8 nucleate embryo sac.
2. The cells within a mature embryo sac play different roles, depending on their location and specialization. Which of the following statements about the organization of the embryo sac is true?
   1. The synergids have structures that play an important role in fertilization.
      1. The synergids have specialized cellular thickenings called the filiform apparatus, that guide the pollen tube into the embryo sac during fertilization.
3. A megaspore mother cell (MMC) divides to form 4 megaspores. If each megaspore has 10 chromosomes, how many chromosomes did the MMC have?
   1. 20
4. 2 megaspore mother cells (MMCs) in a flower undergo megasporogenesis. If this species of plant undergoes monosporic development, how many embryo sacs will develop after megasporogenesis?
   1. 2
5. 5 megaspore mother cells (MMCs) in a flower undergo megasporogenesis. If this species of plant undergoes monosporic development, how many embryo sacs will develop after megasporogenesis?
   1. 5
6. The image below depicts the formation of a mature embryo sac from a functional megaspore. Which of the following events occur in the functional megaspore during this process?

1. Cell walls form after the 4-nucleate stage.
2. Which of the following statements about the structure of cells within the embryo sac is true?
   1. The filiform apparatus can be found in the synergids.
      1. The synergids have cellular thickenings called the filiform apparatus that help guide the pollen tube into them.
3. A megaspore mother cell (MMC) divides to form 4 megaspores. If each megaspore has 50 chromosomes, how many chromosomes did the MMC have?
   1. 100

Types of pollination:

1. Some plants have evolved different mechanisms or characteristics that ensure that pollination only occurs via xenogamy. A botanist is interested in studying these plants, and sets out to obtain some such specimens. Which of the following characteristics should the botanist look for in the plants, to ensure that they only undergo xenogamy?
   1. Only female flowers are present.
      1. If the plant only produces female, it needs pollen from another plant to pollinate it, thus ensuring xenogamy.
   2. Pollen is self-incompatible.
      1. If the flowers of a plant cannot self-fertilize due to incompatible pollen, it can only be pollinated by another plant. This ensures xenogamy, or cross-fertilization.
2. A botanist wishes to introduce new characteristics to a plant. In order to ensure this, she decides to manually pollinate the plant. Which of the following methods of pollination would be most likely to introduce new characteristics to the plant?
   1. Xenogamy
      1. Xenogamy involves cross-fertilization, and so will introduce variations to the plant’s genetic pool. The botanist should carry out xenogamy to increase the chances of new characteristics.
3. The image below depicts the flower of a peanut plant. Based on this image, which of the following statements are most likely to be true?

1. This is a cleistogamous flower, and so will undergo autogamy.
   1. The cleistogamous peanut flower is closed, such that the anthers and stigma are not exposed to the outside world. This makes autogamy necessary, since it can only be pollinated by its own anther.
2. There are 3 plants growing in a garden. The table below lists the types of flowers each plant produces.

Plant A	Plant B	Plant C
Only male flowers	Only female flowers	Both male and female flowers

1. Plant C
   1. Geitonogamy occurs when pollen from one flower lands on the stigma of another flower on the same plant. As plant C has both male and female flowers, it can undergo geitonogamy.
2. A botany museum curator is looking to find specimens for a display on xenogamy. He examines 4 different plants, with flowers that have the following characteristics:
   1. Which of the specimens should the curator choose, as example of xenogamous flowers?

Specimen	Features of flowers
A	Stigma and anthers are fused together
B	Produce sterile pollen, but viable ovules
C	Pollen and stigma mature at different times
D	Self-compatible pollen

1. Specimen B – This specimen can only be fertilized by pollen from another plant, thus ensuring xenogamy, or cross-fertilization.
2. Specimen C – Since this specimen’s pollen is released when the stigma is not receptive, it can only be successfully pollinated via xenogamy, or cross-fertilization.

1. A gardener studies a mutant strain of plant growing in his plot. He realizes that the mutations are due to generations of inbreeding. Which of the following methods of pollination could eventually lead to such mutations?
   1. Autogamy is a form of self-fertilization. Since new genes are never introduced in this method, mutations are likely to accumulate over generations of inbreeding.
   2. Geitonogamy is a form of self-fertilization. Since new genes are never introduced in this method, mutations are likely to accumulate over generations of inbreeding.
2. A gardener grows a rare plant in the hope of cross-pollinating it with another plant. However, when this plant produces flowers, he realizes that it can only undergo autogamy. Which of the following observations could the farmer have made, that would be most likely to explain why only autogamy can occur?
   1. The flowers are cleistogamous.
      1. Cleistogamous flowers are closed, and so the anther and stigma do not get exposed to the environment. In this case, only self-pollination, or autogamy, can occur. This is the most likely explanation for the farmer’s realization.
3. A scientist studies the features of 4 plants growing in a field, and writes down the following observations:

Plant 1	Plant 2	Plant 3	Plant 4
Does not have flowers	Has both male and female flowers	Cannot produce pollen	Flowers lack stigma

1. Which of these 4 plants can undergo geitonogamy?
   1. Plant 2
      1. Geitonogamy occurs when pollen from one flower lands on the stigma of another flower on the same plant. As plant 2 has both male and female flowers, it can undergo geitonogamy.

Pollen-pistil interaction:

1. A few 3-cell pollen grains land on the stigma of a flower. Assuming compatible pollination, which of the following steps will occur next?
   1. The male gametes in the pollen grains move into the pollen tubes.
      1. 3-cell stage pollen grains already contain gametes that can directly move into the pollen tube without the need for any cell division.
   2. The pollen grains transfer their contents to the stigma.
      1. Pollen grains transfer their contents to pollen tubes. The tubes move within the stigma, towards the ovary.
2. A rare disease affects the development of embryo sacs in a plant. These embryo sacs form without the filiform apparatus. How might this altered development affect the plant’s reproductive abilities?
   1. Pollen tubes will not be able to enter the ovary.
      1. The filiform apparatus helps guide the pollen tube into the synergids in the embryo sac. Without the filiform apparatus, this cannot occur.
   2. Fusion of gametes will not occur.
      1. The filiform apparatus is necessary for the entry of male gametes into the embryo sac. Without it, the fusion of gametes cannot occur.
3. A botanist collects pollen from three species of plants (A,B,and C). She dusts the pollen from plant A onto the stigma of its own flowers, as well as those of B and C. She observes that the pollen grains germinate only on the stigma of species B. Which of the following conclusions can the botanist draw from these observations?
   1. Plant A is self-incompatible.
      1. Since the pistil of plant A rejected its own pollen, the botanist can conclude that it is self-incompatible.
   2. Plant B is compatible with plant A
      1. Since the pollen grains from plant A germinated on plant B, the botanist can conclude that the pollen-pistil interaction was successful, and that the two are compatible.
4. A botanist collects pollen from three species of plants (X,Y, and Z). He dusts the pollen from plant Y onto the stigma of its own flowers, as well as those of X and Z. He observes that the pollen grains germinate only on the stigma of species Z Which of the following conclusions can the botanist draw from these observations?
   1. Pistil-pollen interaction will be successful in plant Z.
      1. Since the pollen grains of plant Y germinated on the stigma of plant Z, the botanist will conclude that the two plants are compatible and that the pollen-pistil interaction will be successful.
5. A few 2-celled pollen grains land on the stigma of a flower. Assuming compatible pollination, which of the following steps will occur next?
   1. The generative cell forms male gametes that move into the pollen tubes.
      1. The generative cell in each pollen grain will divide to form 2 male gametes, which will then move into the pollen tube.
6. A botanist places a few grains of pollen on a glass slide, and adds a few drops of sucrose solution to them. Through a microscope, he observes the formation of pollen tubes from the grains, and the movement of male gametes through them. He concludes that the pollen grains were shed at the 3-cell stage. Which of the following explanations could justify his conclusion?
   1. The gametes were already present in the pollen grains, without the need for cell division.
      1. At the 3-cell stage, mitotic division has already occurred to produce male gametes. Since the botanist could observe direct movement of gametes into the pollen tube without any further cell division, he could conclude that the pollen grain was shed at the 3-cell stage.
7. An insect lands on a flower, and in doing so, dusts pollen onto the stigma. The pollen grains germinate to form pollen tubes, which carry male gametes towards the ovary. However, fertilization fails to occur. Further examination of the ovary reveals that the embryo sac has an underdeveloped filiform apparatus that does not function correctly. Why would an underdeveloped filiform apparatus prevent fertilization?
   1. It will be unable to guide pollen tubes into the embryo sac.
      1. The fifliform apparatus is responsible for guiding pollen tubes into the embryo sac via the synergids. If the pollen tube never enters, male and female gametes will never meet to undergo fertilization,
8. A botanist studies the effect of pollination on a flower. She observes the following events:

• The pollen grains on the stigma germinate.
• One of the cells in each pollen grain divides to give rise to gametes.
• Following cell division, pollen grains produce pollen tubes that carry the contents of each grain towards the ovary.

Based on these observations, which of the following conclusions can be drawn about the nature of the pollen grains?

1. They are at the 2-cell stage.
   1. The generative cell in the 2-cell stage pollen grains divides to form gametes before pollen tube formation.

Double fertilization:

1. After double fertilization, an embryo develops at the micropylar end of an embryo sac. If the egg cell had 24 chromosomes, how many chromosomes will the embryo have?
   1. 48
2. After double fertilization, an embryo develops at the micropylar end of an embryo sac. If the egg cell had 50 chromosomes, how many chromosomes will the embryo have?
   1. 100
3. Each haploid nucleus in an embryo sac contains 30 chromosomes. At the end of double fertilization, the primary endosperm nucleus (PEN) is formed within the embryo sac. How many chromosomes will the PEN have?
   1. 90
4. Each haploid nucleus in an embryo sac contains 15 chromosomes. At the end of double fertilization, the primary endosperm nucleus (PEN) is formed within the embryo sac. How many chromosomes will the PEN have?
   1. 45
5. A pollen tube enters an embryo sac via the synergids. Which of the following events will occur next, in order to complete syngamy?
   1. A male gamete fuses with the nucleus of the egg cell.
      1. One of the male gametes released by the pollen tube fuses with the nucleus of the egg cell to form the zygote, thus completing syngamy.
6. The central cell is important for triple fusion, one of the events in the double fertilization process. Which of the following statements correctly describes the role of the central cell in triple fusion?
   1. It contains the polar nuclei that fuse with a male gamete.
      1. During triple fusion, the 2 polar nuclei in the central cell fuse with the nucleus of a male gamete.
7. Which of the following statements correctly describes the structures and events involved in triple fusion?
   1. The polar nuclei fuse with a male gamete.
      1. 2 polar nuclei in the central cell fuse with the nucleus of a male gamete to eventually form the primary endosperm cell.
8. A scientist studies an embryo sac under a special microscope, and notices that syngamy is underway. Which of the following events will she observe during this process?
   1. The nucleus of the egg cell fuses with 1 male gamete.
      1. One of the gametes released by the pollen tube fuses with the nucleus of the egg cell, forming the zygote and thus completing syngamy.