Tag: the origin of cells and cell division

Questions Related to the origin of cells and cell division

In mesogamy, pollen tube enters the ovule through

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Middle of integuments after piercing the tissues

  2. Middle of integuments without piercing the tissues

  3. Chalaza

  4. Middle of micropyle

Show answer
Correct Option: A
Explanation:
Mesogamy is the entry of pollen tube in the ovule through the integuments. The pollen tube enters the ovule laterally through integuments by piercing the tissue in the middle and finally enters the embryo sac through micropylar pole, whereas, entry of pollen tube through chalaza is called chalazogamy and through micropyle is called porogamy.
So, the correct answer is A. 

Pollen tube discharges its male gametes into.

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Egg

  2. Healthy synergid

  3. Degenerating synergid

  4. Central cell

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Correct Option: C

Plant part having two generations, one within the other is?

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Seed

  2. Germinated pollen grain

  3. Embryo

  4. Unfertilized ovule

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Correct Option: D

Entry of pollen tube through chalazal end is

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Syngamy

  2. Porogamy

  3. Mesogamy

  4. Basigamy

Show answer
Correct Option: D
Explanation:
•Syngamy is the fusion of male and female gamete which results in the formation of a diploid zygote.
•Porogamy is the entry of pollen tube in the ovule through micropyle.
•Mesogamy is the entry of pollen tube in the ovule through the integuments or nucellus.
•Basigamy is also known as Chalazogamy. It is the entry of pollen tube in the ovule through the chalaza.
So, the correct answer is D.

Pollen tube usually enters the embryo sac

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Through one of the synergids.

  2. Directly penetrates the egg.

  3. Between one synergid and central cell.

  4. By knocking of antipodal cells.

Show answer
Correct Option: A
Explanation:
Synergids attract the pollen tube by secreting some chemotactic substances and guide the pollen tube entry. Synergids are ephemeral i.e. short-lived structures. In embryo sacs, which have two synergids, one synergid degenerates before the entry of pollen tube. This degenerated synergid provides the way for pollen tube entry in the embryo sac. The pollen tube discharges its content in the degenerated synergid. The other synergid which is the persistent synergid degenerates shortly after the pollen tube has released its contents in the embryo sac.
Hence, pollen tube enters the embryo sac through one of the synergids.
So, the correct answer is A.

Commonly the pollen tube enters the ovule through

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Hilum

  2. Chalaza

  3. Funicle

  4. Micropyle

Show answer
Correct Option: D
Explanation:
Pollen tube may enter the ovule via any of the following routes:
1.  Porogamy- when the pollen tube enters the ovule through micropyle. It is common in most of the angiosperms.
2. Mesogamy- when the pollen tube enters through the integuments or through funiculus.
3. Chalazogamy- when the pollen tube enters through the chalazal tissues.
Thus, pollen tube commonly enters the ovule through micropyle.
So, the correct answer is D.

Based on entry of pollen tube into ovule, which one is mesogamy.

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Through micropyle

  2. Entry through funiculus, chalaza and embryo sac from egg apparatus end

  3. Through placenta and funiculus

  4. Through integument

Show answer
Correct Option: C

Normally how many pollen mother cells are necessary for formation of $400$ seeds.

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. $200$

  2. $500$

  3. $100$

  4. $400$

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Correct Option: C

Through which cell of the embryo sac, does the pollen tube enter the embryo sac-

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Persistant synergid

  2. Egg cell

  3. Central cell

  4. Degenerated synergid

Show answer
Correct Option: D
Explanation:

The pollen tube enters the embryo sac through the micropylar end. It can enter directly through the synergid or can enter from between the egg cell and synergid.

The answer is D- Degenerated synergid. 
So the correct option is D.

The element known to be involved in the polarized growth of pollen tube is?

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Potassium

  2. Magnesium

  3. Sodium

  4. Calcium

Show answer
Correct Option: A