Question 1

Match the following with respect to meiosis(a) Zygotene (i) Terminalization(b) Pachytene (ii) Chiasmata(c) Diplotene (iii) Crossing over(d) Diakinesis (iv) SynapsisSelect the correct option from the following

Accepted Answer

Zygotene   	→  	SynapsisPachytene	→ 	Crossing overDiplotene   	→ 	Chiasmata formationDiakinesis  	→ 	Terminalisation

Question 2

Dissolution of the synaptonemal complex occurs during:

Accepted Answer

Dissolution of the synaptonemal complex occurs During Diplotene stage of Prophase-I of Meiosis-I.

Question 3

The stage during which separation of the paired homologous chromosomes begins is

Accepted Answer

Synaptonemal complex disintegrates. Terminalisation begins at diplotene stage i.e. chiasmata start to shift towards end.

Question 4

In meiosis crossing over is initiated at :

Accepted Answer

In pachytene recombination nodule is formed after which crossing over occurs.

Question 5

Meiosis takes place in:

Accepted Answer

Meiocyte are the cells in which meiosis occur.

Question 6

Arrange the following events of meiosis in correct sequence(a) Crossing over(b) Synapsis(c) Terminalisation of chaismata(d) Disappearance of nucleolus

Accepted Answer

The sequence of event during meiosis are(1) Synapsis (Zygotene)(2) Crossing over (Pachytene)(3) Terminalisation of chiasmata(4) Disappearance of nucleolus

Question 7

Name the stage of cell cycle at which one of the following events occur:(i) Chromosomes are moved to spindle equator.(ii) Centromere splits and chromatids separate.(iii) Pairing between homologous chromosomes takes place.(iv) Crossing over between homologous chromosomes takes place.

Accepted Answer

(i) Metaphase(ii) Anaphase(iii) Zygotene of meiosis I(iv) Pachytene of meiosis I

Question 8

Describe the following: (a) Synapsis (b) Bivalent (c) ChiasmataDraw a diagram to illustrate your answer.

Accepted Answer

(a) Synapsis : The pairing of homologous chromosomes is called as synapsis. This occurs during the second stage of prophase I or zygotene.(b) Bivalent : Bivalent or tetrad is a pair of synapsed homologous chromosomes. They are formed during the zygotene stage of prophase I of meiosis.(c) Chiasmata : Chiasmata is the site where two non-sister chromatids have crossed over. It represents the site of cross-over. It is formed during the diplotene stage of prophase I of meiosis.

Question 9

Find examples where the four daughter cells from meiosis are equal in size and where they are found unequal in size.

Accepted Answer

(a) Spermatogenesis or the formation of sperms in human beings occurs by the process of meiosis. It results in the formation of four equal-sized daughter cells.(b) Oogenesis or the formation of an ovum in human beings occurs by the process of meiosis. It results in the formation of four daughter cells which are unequal in size, i.e., a big mature ovum and 3 small polar bodies.

Question 10

What is the significance of meiosis?

Accepted Answer

The significance of meiosis is given below:(i) Formation of gametes - Meiosis forms gametes that are essential for sexual reproduction.(ii) Genetic information - It switches on the genetic information for the development of gametes or gametophytes and switches off the sporophytic information. Ã¢â‚¬Ëœ(iii) Maintenance of chromosome number - Meiosis maintains the fixed number of chromosomes in sexually reproducing organisms by halving the same. It is essential since the chromosome number becomes double after fertilisation.(iv) Assortment of chromosomes - In meiosis paternal and maternal chromosomes assort independently. It causes reshuffling of chromosomes and the traits controlled by them. The variations help the breeders in improving the races of useful plants and animals.(v) Crossing over - It introduces new combination of traits or variations.(vi) Mutations - Chromosomal and genomic mutations can take place by irregularities of meiotic divisions. Some of these mutations are useful to the organism and are perpetuated by natural selection.(vii) Evidence of basic relationship of organisms - Details of meiosis are essentially similar in the majority of organisms showing their basic similarity and relationship.

Question 11

At metaphase, chromosomes are attached to the spindle fibres by their :

Accepted Answer

The key feature of metaphase is the attachment of spindle fibres to kinetochores of chromosomes. Kinetochores are disc-shaped structures at the surface of the centromeres. These structures serve as the sites of attachment of spindle fibres to the chromosomes that are moved into position.

Question 12

Segregation of genes occurs in :

Accepted Answer

Anaphase I begins when the two chromosomes of each bivalent (tetrad) separate and start moving toward opposite poles of the cell as a result of the action of the spindle. Anaphase is important stage of cell division. It ensures that duplicated chromosomes, or sister chromatids, separate into two equal sets. This separation of chromosomes is called disjunction. Each set of chromosomes will become part of a new cell.

Question 13

Arrange the following events of meiosis in correct sequence(i) Crossing over(ii) Synapsis(iii) Terminalisation of chiasmata(iv) Disappearance of nucleolus

Accepted Answer

During Meiosis I the first step is synapsis to form the synaptonemal complex.After that crossing over between the homologous chromosome takes place.Then after crossing over terminalisation of chiasmata happens.After that, the nucleolus gets disappeared.

Question 14

Meiosis II performs

Accepted Answer

Meiosis II is shorter than the typical mitotic division because of the shortening of prophase of this division. The division maintains the number of chromosomes produce at the end of reduction division. Hence, it is called homotypic or equational division, though it is similar to mitosis. The main function of homotypic division or meiosis II is to separate the chromatids of univalent chromosomes which differ from each other in their linkage groups due to crossing over.

Question 15

When paternal and maternal chromosomes change their materials with each other in cell division this event is called

Accepted Answer

Crossing over is responsible for inducing variability. It involves an exchange of equal segments of non-sister chromatids belonging to two different but homologous chromosomes. Crossing over takes place at four stranded stage. Only two of the four chromatids take part in crossing over. The other two are called non crossovers. Zygotene is characterized by pairing of homologous chromosomes which is called synapsis.

Question 16

The enzyme recombinase participates in which of the following stages during gamete formation,

Accepted Answer

During gamete formation, the enzyme recombinase participates during pachytene stage of prophase I. This stage is characterized by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes. Crossing over is the exchange of genetic material between two homologous chromosomes. Crossing over is also an enzyme-mediated process and the enzyme involved is called recombinase.

Question 17

The enzyme recombinase is required at which stage of meiosis?

Accepted Answer

Pachytene stage is characterized by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes. Nodules contain multi enzyme complex called recombinase.

Question 18

Number of chromatids at metaphase is

Accepted Answer

Number of chromatids at metaphase is two each in mitosis and meiosis. Chromatid is a half chromosome during duplication in early prophase and metaphase of mitosis and between diplotene and the second metaphase of meiosis. After these stages chromatids are called a daughter chromosomes.

Question 19

Dissolution of the synaptonemal complex occurs during ?

Accepted Answer

During diplotene in prophase I of meiosis I dissolution of the nucleoprotein synaptonemal complex occurs.

Question 20

Crossing over takes place between which chromatidsand in which stage of the cell cycle ?

Accepted Answer

Crossing over is a process of the exchange of genetic material or chromatid segments between non-sister chromatids of two homologous chromosomes. It is initiated during the pachytene stage of meiosis.

Filters

Filters

class

subject

topic

concept

difficulty

Solutions for Meiosis Important Questions

Found the solution, but did not understand the concept?

Ask my first question