Tag: botany

Quizzes (264) Questions (5276)

Questions Related to botany

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

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

  1. $200$
  2. $500$
  3. $100$
  4. $400$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Each seed requires one male gamete and one female gamete. One pollen mother cell (PMC) produces 4 microspores, each forming a pollen grain with 2 male gametes. However, only one pollen grain is needed per seed. Thus, 400 seeds require 400 pollen grains. Since 1 PMC produces 4 microspores, 400/4 = 100 PMCs are needed.

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

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

  1. Persistant synergid

  2. Egg cell

  3. Central cell

  4. Degenerated synergid
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

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

  1. Potassium

  2. Magnesium

  3. Sodium

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

Calcium ions play a crucial role in establishing and maintaining the tip growth polarity of pollen tubes by regulating vesicle fusion and actin cytoskeleton dynamics at the apex.

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

When pollen tube enters through microphyte, the process is called _______________.

  1. Porogamy

  2. Chalazogamy

  3. Mesogamy

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

Porogamy is the term for pollen tube entry through the micropyle (the small opening in the ovule integuments). Chalazogamy is entry through the chalaza, and mesogamy is through the integument. Apogamy refers to asexual reproduction without fertilization. Note: the question has a typo - it says 'microphyte' but means 'micropyle'.

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

When a dicot plant is infected by Agrobacterium tumefaciens, the T-DNA in Ti-plasmid induces the plant to produce?

  1. Growth hormones like auxins and cytokinins

  2. Growth inhibitors like absciscic acid

  3. Fatty acids

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

Agrobacterium tumefaciens is the causal agent of crown gall disease (the formation of tumours). It is a rod-shaped, Gram-negative soil bacterium. The plasmid of this bacterium is called Ti-plasmid, it shows T-DNA. This plasmid used to produce growth hormones like auxins and cytokinins.

So, the correct option is ‘Growth hormones like auxins and cytokinins’.

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

Length of pollen tube depends on the distance between

  1. Pollen grain and upper surface of stigma

  2. Pollen grain on upper surface of stigma and ovule

  3. Pollen grain in anther and upper surface of stigma

  4. Upper surface of stigma and lower part of style
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Length of pollen tube depends upon distance of pollen on stigma and ovule because after pollination pollen germinates and form pollen tube that reaches upto ovule in ovary and release male gamete to fuse with female gamete.

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

Mesogamy is

  1. Fusion of similar male and female gametes

  2. Fusion of morphologically different but physiologically similar gametes

  3. Entry of pollen tube through the integument

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

There are various ways by which the pollen tube can reach embryo sac for pollination.

Porogamy is the condition when the pollen tube enters the ovule from the micropylar end. Chalazogamy is the condition of entering of pollen tube from chalaza. Mesogamy is when pollen tube enters via the integuments.
Fusion of male and female gametes refers to as fertilization or fusion of gametes.
So, the correct option is 'entry of the pollen tube through the integument'. 

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

What is the function of the filiform apparatus at the entrance into ovule?

  1. Guides pollen tube from synergid to egg

  2. Helps in the entry of pollen tube into a synergid

  3. Prevents entry of more than one pollen tube into a synergid

  4. Brings about opening of the pollen tube
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A fully developed typical or polygonum type of embryo sac is a large and oval structure consisting of 7 cells and 8 nuclei.
Egg apparatus- this is a group of 3 cells situated at the micropylar end. The centrally located cell is known as the egg cell. On its sides are present two synergids. An egg cell has a large vacuole at its upper end and a prominent nucleus near its lower end. Synergids show of filiform apparatus attached to the upper wall. It is known to attract and guide the pollen tube. Each of the synergies has a vacuole at its lower end and the nucleus at its upper end.

So, the correct option is 'Helps in the entry of the pollen tube into a synergid'.
Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

What is the function of filiform apparatus in an angiospermic embryo sac?

  1. Guides pollen tube from synergid to egg

  2. Helps in the entry of more than one pollen tube into a synergid

  3. Prevents entry of more than one pollen tube into a synergid

  4. Brings about opening of the pollen tube.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The function of filiform apparatus in an angiospermic embryo sac is to guide the entry of pollen tube from synergid to egg. The synergid cells present within the female gametophyte play a vital role in the reproduction process in angiosperm. The cell wall of synergid develops an extremely thick structure called the filiform apparatus at the micropylar end of the ovule.

So, the correct answer is 'Guides pollen tube from synergid to egg'.

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

The most common type of entry of pollentube into the ovule is

  1. Mesogamy

  2. Chalazogamyy

  3. Basigamy

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

Porogamy is the most common type in which the pollen tube enters the ovule through the micropyle. An example includes lily, etc. 

So the correct option is D.