Tag: pre fertilization - plants

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Multiple choice botany asexual and sexual reproduction in plants introduction to flower pre fertilization - plants modes of reproduction

Meiotic division occurring just at the time of gametogenesis is 

  1. Sporic

  2. Initial

  3. Intermediate

  4. Terminal
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • In plants, meiosis is occurring as in diploid sporophyte to produce haploid spores. 
  • The haploid spores are germinating to produce structures called gametophytes. The gametophytes then produce gametes. 
  • Gametic or the terminal meiosis occurs in all multicellular animals. It takes place in the gonads and hence as results in the formation of gametes. 
  • It is responsible for gametogenesis and does not give rise to gametophytes.
  • The correct option is D.

Multiple choice botany asexual and sexual reproduction in plants introduction to flower pre fertilization - plants modes of reproduction

Development of female gametophyte directly from megaspore mother cell without meiosis is called.

  1. Apogamy

  2. Apospory

  3. Syngamy

  4. Parthenospore
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Apospory is the development of a gametophyte directly from the sporophyte tissue (like the megaspore mother cell) without meiosis, resulting in a diploid gametophyte.

Multiple choice botany asexual and sexual reproduction in plants introduction to flower pre fertilization - plants modes of reproduction

Read the given statements.


(i) The outer exine is made up of sporopollenin.
(ii) Inner intine is pecto-cellulosic in nature.
(iii) Generative cell is bigger and contains abundant food reserve.
(iv) Vegetative cell is small and floats in the cytoplasm of the generative cell.

Which of the given statements are not true regarding the structure of pollen grain?

  1. (i) and (ii)

  2. (ii) and (iii)

  3. (iii) and (iv)

  4. (i) and (iv)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In a mature pollen grain, the generative cell is smaller and the tube(or vegetative) cell is larger. In the later stages of development of pollen grain, callose dissolves and the naked generative cell comes to lie freely in the cytoplasm of the tube cell. The tube cell has a cytoplasm that is rich in the food reserve (starch, protein, fat with mostly unsaturated fatty acids).

Multiple choice botany life processes in living organisms- part 1 introduction to flower pre fertilization - plants modes of reproduction

Sporic meiosis occurs in

  1. Animals

  2. Thallophyta

  3. Bryophyta

  4. All plants except thallophyta
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sporic meiosis, has mitosis in two stages, both the diploid and haploid stages, termed diplobiontic. 

Sporic meiosis occurs in all plants except thallophyta. In sporic meiosis, the division by mitosis happens to create a multicellular diploid organism, the sporophyte. Some of the cells of the sporophite then produce spores through a sporic meiosis. In this case, the meiosis is sporic (because it produces spores). The spores then produce a haploid gametophyte which, in turn, will produce the gametes through mitosis. 

Multiple choice botany asexual and sexual reproduction in plants introduction to flower pre fertilization - plants modes of reproduction

$32$ chromosomes are present in the green leaf of Onion. When meiosis takes place to produce gametes after fertilization how many chromosomes will be there in triploid nucleus.

  1. $32$
  2. $16$
  3. $48$
  4. $9$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If the leaf (diploid) has 32 chromosomes, the gametes (haploid) have 16. Fertilization of an egg (16) by a sperm (16) produces a zygote (32). The triploid nucleus (endosperm) is formed by the fusion of two polar nuclei (16+16) and one male gamete (16), resulting in 48 chromosomes.