Tag: modes of reproduction

Questions Related to modes of reproduction

Fusion between a larger non-motile (static) female gamete and smaller motile male gamete is

botany modes of reproduction fertilization in organisms sexual reproduction in organisms reproduction in organisms

  1. Isogamous

  2. Oogamous

  3. Anisogamous

  4. Homogamous

Show answer
Correct Option: B
Explanation:

Isogamy is the fusion of gametes that are similar in similar sizes. Anisogamy involves fusion of gametes that are dissimilar in sizes where both gametes are either motile or immobile.

In oogamy, female gamete is static while male gamete is small and motile.
So, the correct option is 'Oogamous'.

In oogamous reproduction,

botany modes of reproduction fertilization in organisms sexual reproduction in organisms reproduction in organisms

  1. Both male and female gametes are motile

  2. Both gametes are product of division of protoplast

  3. Both male and female gametes are non-motile

  4. For male gametes protoplast divides but for female gamete it does not

Show answer
Correct Option: D
Explanation:

  • Oogamy is a system of sexual reproduction in which one gamete (called the egg) is large and nonmotile, while the other (called the sperm) is small and motile. Oogamy is a type of Anisogamy.
  • During Spermatogenesis, the protoplast of spermatogonium is equally divided into 4 spermatids while during oogenesis, ovum retains the bulk of protoplast and is minimally shared by Polar bodies.
So, the correct option is 'For male gametes protoplast divides but for female gamete it does not'.

Select the wrong statement :

botany modes of reproduction fertilization in organisms sexual reproduction in organisms reproduction in organisms

  1. Chlamydomonas exhibits both isogamy and anisogamy and Fucus shows oogamy.

  2. Isogametes are similar in structure, function and behaviour.

  3. Anisogametes differ either in structure, function or behaciour.

  4. In oomycetes, female gamete is smaller and motile while male gamete is larger and non-motile.

Show answer
Correct Option: B

Choose the correct answers from the alternatives given.
The principal embryonic membranes are

botany modes of reproduction fertilization in organisms sexual reproduction in organisms reproduction in organisms

  1. Chorion and umbilicus

  2. Amnion and placenta

  3. Amnion and chorion

  4. Placenta and umbilicus

Show answer
Correct Option: C
Explanation:
The placenta is an ephemeral organ found only in eutherian mammals during gestation. Placenta is the only organ composed of cells derived from two different organisms i.e. from the fetus and the mother. The fetal membranes are chorion and amnion. The membranes from the uterine wall are deciduas basalis. It is the portion of the deciduas which is directly adjacent to conception at the implantation site. Decidua is a mucous membrane lining the uterus during pregnancy and it cast off during childbirth. After the implantation of the embryo, the uterine endometrium is called decidua. Thus the principal embryonic membranes are Amnion and chorion.
So the correct option is ' Amnion and chorion '.

What is the function of germ pore?

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

  1. Emergence of radicle

  2. Absorption of water for seed germination

  3. Initiation of pollen tube

  4. All of these

Show answer
Correct Option: C
Explanation:

One or more thin areas present in the exine of pollen grains are known as germ pores. The germ pores are apertures in the exine layer of the pollen grain where the sporopollenin is absent. The germ pore helps in the formation of the pollen tube and the release of the male gametes during fertilisation. There are usually three germ pores in dicots(tricolpate) and one in monocots(monocolpate).

In Casuarina, fertilization occurs by 

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

  1. Chalazogamy

  2. Mesogamy

  3. Porogamy

  4. Apogamy

Show answer
Correct Option: A
Explanation:
  • Pollen tube eventually reaches the micropyle of an ovule to enter the embryo sac and for this purpose, it may follow one of the following three routes:
  • 1. Porogamy- when the pollen tube enters the ovule through the micropyle. It is common for most of the angiosperms.
  • 2. Mesogamy- when the pollen tube enters through the integuments (Cucumber) or through funiculus (Pistacia).
  • 3. Chalazogamy- when the pollen tube enters through the chalazal tissues. For example, Casuarina.
Hence In Casuarina, fertilization occurs by Chalazogamy.
  • So, the correct answer is 'Chalazogamy'.

Chalazogamy occurs in

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

  1. Cucurbita

  2. Lily

  3. Populus

  4. Casuarina

Show answer
Correct Option: D
Explanation:
Chalazogamy is the entry of pollen tube in the ovule through chalazal tissue. It occurs in plants like Casuarina. In Cucurbita and Populus, pollen tube enters the ovule through the integuments and this is known as mesogamy. In Lily, pollen tube enters the ovule through the micropyle and this is known as porogamy.
So, the correct answer is A.

The phenomenon of pollen tube entering the ovule laterally through integuments is called

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

  1. Mesogamy

  2. Aporogamy

  3. Chalazogamy

  4. Vegetative fertilization

Show answer
Correct Option: A
Explanation:
•Mesogamy is the entry of pollen tube through the integuments.
•Aporogamy is the condition in which pollen tube enters the ovule through a path other than micropyle.
•Chalazogamy is the entry of pollen tube through chalaza.
•Vegetative fertilisation is a part of double fertilisation in Angiosperms, in which one of the two male gametes fuses with the diploid secondary nucleus and this results in the formation of a triploid primary endosperm mother cell. It is also known as triple fusion.
So, the correct answer is A.

In Casuarina, fertilization takes place through

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

  1. Mesogamy

  2. Porogamy

  3. Chalazogamy

  4. Apogamy

Show answer
Correct Option: C
Explanation:
• Mesogamy is the entry of pollen tube in the ovule through the integuments (e.g. Cucurbita) or through funiculus (e.g. Pistacia).
• Porogamy is the entry of pollen tube in the ovule through the micropyle. It occurs in most of the angiosperms.
• Chalazogamy is the entry of pollen tube in the ovule through the chalazal tissues. Example, Casuarina.
• Apogamy is a type of reproduction in which sporophyte develops directly from the gametophyte without the fusion of gametes.
Hence, in Casuarina fertilization takes place through Chalaza, as pollen tube enters the ovule from Chalaza to release the male gametes which will fuse with the egg cell and central cell, resulting in fertilization.
So, the correct answer is C.

In ovule, exostome is

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

  1. Area just outside the micropyle

  2. Area at the tip of nucellus

  3. Part of micropyle enclosed by inner integument

  4. Part of micropyle enclosed by outer integument

Show answer
Correct Option: D
Explanation:

In an ovule, an opening is formed at the tip of ovule by the integuments called as micropyle. The micropyle acts as a pore for the entry of pollen tube into the ovule for fertilization. In bitegmic ovules, the opening is formed by the inner integument and is called endostome. If the opening is formed by the outer integument it is called exostome. Sometimes it is formed by both the integuments, then it is called as amphistome. 

Thus, the correct answer is option D.