Tag: alternation of generation in angiosperms

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Multiple choice botany modes of reproduction alternation of generation in angiosperms alternation of generation angiosperms

Life cycle of Saccharomyces cerevisiae is 

  1. Haplontic

  2. Diplontic

  3. Haplodiplontic

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Three types of life cycle patterns are seen in the Saccharomyces (yeasts).

(i)         Haplobiontic life cycle (Saccharomyces octopus)

(ii)        Diplobiontic life cycle (Saccharomyces ludwigii)

(iii)       Haplodiplontic life cycle (Saccharomyces cerevisiae)

The correct option is C.

Multiple choice botany modes of reproduction alternation of generation in angiosperms alternation of generation angiosperms

Comparable to angiosperms which of the following alga exhibits diplontic life cycle?

  1. Spirogyra

  2. Ectocarpus

  3. Fucus

  4. Polysiphonia
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  • Fucus (rockweed) is a type of brown alga and it displays the diploid life history. 
  • The zygote becomes the embryo and develops into the mature Fucus. 
  • The receptacles are reproductive branches and so contain many cavities with external pores. These pores contain antheridia (male) and oogonia (female)
  • The correct option is C.

Multiple choice botany modes of reproduction alternation of generation in angiosperms alternation of generation angiosperms

Which one of the following shows the last diploid stage in the life cycle of angiosperms?

  1. Microspore mother cell

  2. Zygote

  3. Nucellus

  4. Pollen grain
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A. Microspore mother cell or MMC is the diploid germ cell which forms microspores (pollen) by the process of microsporogenesis.
B. Zygote is the diploid structure formed by the fusion of male and female gametes.
C. Nucellus is the central part of ovule in which embryo is present. It is triploid.
D. Pollen grain or microspore is the haploid male gamete.
In the life cycle of angiosperms, zygote gives rise to a complete plant. The plant has germ cells which are diploid and produce gametes. The gametes then fuse to form a zygote. Hence, microspore mother cell is the last diploid stage because after that, haploid gametes are formed.
So, the correct answer is 'Microspore mother cell'.
Multiple choice botany modes of reproduction alternation of generation in angiosperms alternation of generation angiosperms

Which of the statements regarding haplontic life cycle is incorrect?

  1. Sporophytic generation is represented only by the one-celled zygote.

  2. There is no free-living sporophyte.

  3. Mitosis in the zygote results in the formation of haploid spores.

  4. The haploid spores divide mitotically and form the gametophyte.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In a haplontic life cycle, the plant body is a gametophyte and dominant a dominant phase. The reproductive cell undergo mitosis to form gametes that are haploid, the gametic fusion results in a diploid zygote, which undergoes meiosis to form haploid spores.

So, the correct answer is 'Mitosis in the zygote results in the formation of haploid spores.'

Multiple choice botany modes of reproduction alternation of generation in angiosperms alternation of generation angiosperms

Which one of the following has haplontic life cycle ?

  1. Wheat

  2. Funaria

  3. Polytrichum

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

Ustilago is a genus of around 200 smut fungi parasitic on the grasses. In the haplontic life cycle, the haploid stage is multicellular whereas the diploid stage is a single cellular. The zygote undergoes meiosis to form the haploid spores. Each spore germinates are being divided to form gametophyte. The other three are not having this life cycle.

So, the correct answer is option D.

Multiple choice botany modes of reproduction alternation of generation in angiosperms alternation of generation angiosperms

Haplo-diplontic life cycle is observed in how many of the following plants.
Pinus, Sphagnum, Polytrichum, Polysiphonia, Dryopteris, Riccia, Marchantis, Pteris, Selaginella, Ectocarpous, Volvox.

  1. $6$
  2. $7$
  3. $8$
  4. $9$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Haplo-Diplontic life cycle observed in 8 in following plants. This life cycle present only in Bryophytes and pteridophytes. So, sphagum, polytrichum, marchantis and riccia belongs to Bryophyta and selaginella, pteris, dryopteris and polysiphonia belongs to pteridophyta. That's why they consists Haplo-Diplontic life cylcle. 

Multiple choice botany modes of reproduction alternation of generation in angiosperms alternation of generation angiosperms

A diploid parent plant body produces _______ gametes and a haploid parent plant body produces _________ gametes.

  1. Diploid, haploid

  2. Haploid, diploid

  3. Diploid, diploid

  4. Haploid, haploid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A diploid parent plant body produces haploid gametes (by reductional division) and a haploid parent plant body produces haploid gametes (by equational division). As the gametes are to be haploid since after union they will re-establish the ploidy level similar to the parent generation.
So, the correct answer is 'Haploid, haploid'.
Multiple choice biology plant kingdom alternation of generation in angiosperms alternation of generation angiosperms

The gametophyte of  Bryophytes reproduction sexually by Isogamy Physiological anisogamy

  1. Isogamy

  2. Physiological anisogamy

  3. Siphanogamous oogamy

  4. Zooidogamous oogamy
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In Bryophytes, sexual reproduction is oogamous, but the gametes are often described in terms of their fusion. Isogamy is a primitive form where gametes are identical, but Bryophytes generally exhibit more advanced forms.