12th Grade > Biology
GROWTH & REPRODUCTION IN PLANTS AND ANIMALS MCQs
Plant Growth And Development, Reproduction In Animals, Sexual Reproduction In Flowering Plants
Total Questions : 111
| Page 6 of 12 pages
Answer: Option A. -> Vegetative cell was not damaged
:
A
In the scenario given, a generative cell wall was destroyed by laser but a normal pollen tube still formed as the vegetative cell was not damaged. Each microspore divides by mitotic division making a smaller generation cell and a larger vegetative cell or tube cell. If the generative cell was damaged then a normal pollen tube will still form because it is formed by the vegetative cell not by the generative cell.
:
A
In the scenario given, a generative cell wall was destroyed by laser but a normal pollen tube still formed as the vegetative cell was not damaged. Each microspore divides by mitotic division making a smaller generation cell and a larger vegetative cell or tube cell. If the generative cell was damaged then a normal pollen tube will still form because it is formed by the vegetative cell not by the generative cell.
Answer: Option B. -> (i)- Antipodals, (ii)- Polar nuclei, (iii)- Central cell, (iv)- Egg cell, (v)- Synergids
:
B
The embryo sac is the female gametophyte in angiosperms. It consists of 7-cells and 8 nuclei at maturity. Three cells present at chalazal end of the ovule are called antipodals. Three cells present at the micropylar end are collectively knownas the egg apparatus. Egg apparatus consists of one egg cell and two synergids. In between egg apparatus and antipodals is the central cell whichhas two polar nuclei.
:
B
The embryo sac is the female gametophyte in angiosperms. It consists of 7-cells and 8 nuclei at maturity. Three cells present at chalazal end of the ovule are called antipodals. Three cells present at the micropylar end are collectively knownas the egg apparatus. Egg apparatus consists of one egg cell and two synergids. In between egg apparatus and antipodals is the central cell whichhas two polar nuclei.
Answer: Option D. -> (i) - Mitosis, (ii) - Meiosis
:
D
Sporogenous tissue undergoes mitosis and produce many microspore mother cells. Each microspore mother cell undergoes meiosis (reduction division) to form microspore tetrads where each microspore develops and maturesto form the male gametophyte or pollen grain.
:
D
Sporogenous tissue undergoes mitosis and produce many microspore mother cells. Each microspore mother cell undergoes meiosis (reduction division) to form microspore tetrads where each microspore develops and maturesto form the male gametophyte or pollen grain.
Answer: Option C. -> Both A and B
:
C
Storage is the preservation of viable seeds from the time of collection until they are required for sowing. Seeds form the basis for agriculture and their property of dehydration and dormancy are crucial for their storage which can be used as food throughout the year. At maturity, seeds lose about 90% of their water, which slows their metabolism significantly leading to dormancy, a period during which the embryo puts its development on hold.
:
C
Storage is the preservation of viable seeds from the time of collection until they are required for sowing. Seeds form the basis for agriculture and their property of dehydration and dormancy are crucial for their storage which can be used as food throughout the year. At maturity, seeds lose about 90% of their water, which slows their metabolism significantly leading to dormancy, a period during which the embryo puts its development on hold.
Question 55. Regarding assertion and reason, select the right option.
Assertion (A): Plants pollinated by abiotic agents produce enormous amount of pollen when compared to plants pollinated by biotic agents.
Reason(R): Pollen grains coming in contact with stigma is a chance factor in anemophily and hydrophily.
Assertion (A): Plants pollinated by abiotic agents produce enormous amount of pollen when compared to plants pollinated by biotic agents.
Reason(R): Pollen grains coming in contact with stigma is a chance factor in anemophily and hydrophily.
Answer: Option A. -> A and R are correct and R explains A
:
A
In anemophily and hydrophily, pollen reaching the compatible stigma is an affair, totally dependent on chance. Hence, there is more wastage. To increase the probability of successful pollination, pollen grains are produced in large numbers here.
:
A
In anemophily and hydrophily, pollen reaching the compatible stigma is an affair, totally dependent on chance. Hence, there is more wastage. To increase the probability of successful pollination, pollen grains are produced in large numbers here.
Answer: Option B. -> False
:
B
Cryptogamae includes those plants that do not bear flowers and seeds and reproduce asexually by means of spores. Bryophytes (mosses, liverworts and hornworts) are cryptogams. Bryophytes are in complete contact with water and hence do not require vascular tissue. It is the pteridophytes in fact who are called 'vascular cryptogams' due to the presence of vascular tissue.
:
B
Cryptogamae includes those plants that do not bear flowers and seeds and reproduce asexually by means of spores. Bryophytes (mosses, liverworts and hornworts) are cryptogams. Bryophytes are in complete contact with water and hence do not require vascular tissue. It is the pteridophytes in fact who are called 'vascular cryptogams' due to the presence of vascular tissue.
Answer: Option C. -> (i)-(c), (ii)-(a), (iii)-(b), (iv)-(d) , (v)-(e)
:
C
Nucellus is the nutritive tissue present inside the ovule. It is the actual megasporangium which has developed from the megaspore mother cell during megasporogenesis. Hence, ovule is the integumented megasporangium. Micropyle is the apical pore through which pollen tube enters the ovule. Opposite to micropyle, the tissue connecting the nucellus and the integuments is the chalaza which forms the basal part of the ovule.
:
C
Nucellus is the nutritive tissue present inside the ovule. It is the actual megasporangium which has developed from the megaspore mother cell during megasporogenesis. Hence, ovule is the integumented megasporangium. Micropyle is the apical pore through which pollen tube enters the ovule. Opposite to micropyle, the tissue connecting the nucellus and the integuments is the chalaza which forms the basal part of the ovule.
Answer: Option B. -> synergids
:
B
Filliform apparatus is a mass of finger like projections of the wall into the cytoplasm. It is present in synergids of the embryo sac, in the micropylar region. It guards the pollen tube inside the ovule towards the embryo sac.
:
B
Filliform apparatus is a mass of finger like projections of the wall into the cytoplasm. It is present in synergids of the embryo sac, in the micropylar region. It guards the pollen tube inside the ovule towards the embryo sac.
Answer: Option D. -> 50
:
D
Total diploid set of chromosomes in Maize plant is 20. During gamete formation the number becomes 10 on meiotic division. Therefore, the male gametes and the cells of the embryo sac will have chromosome number 10. Since, two haploid sperms, one haploid egg and a diploid polar nuclei is involved in double fertilisation, the number of chromosomes involved in double fertilisation in maize will be 10 +10 +10 +20 = 50.
:
D
Total diploid set of chromosomes in Maize plant is 20. During gamete formation the number becomes 10 on meiotic division. Therefore, the male gametes and the cells of the embryo sac will have chromosome number 10. Since, two haploid sperms, one haploid egg and a diploid polar nuclei is involved in double fertilisation, the number of chromosomes involved in double fertilisation in maize will be 10 +10 +10 +20 = 50.
Answer: Option A. -> Fusion of gametes
:
A
Syngamy means fusion of gametes. Syngamy is the phenomenon in which male gametes fuses with the egg in the embryo sac of flowering plants.
:
A
Syngamy means fusion of gametes. Syngamy is the phenomenon in which male gametes fuses with the egg in the embryo sac of flowering plants.
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