Answer to Question #164767 in Genetics for abdullah

Question

Which of the following statements characterize meiosis II? Select all that apply.

Multiple select question.

A)

Homologous chromosomes line up at the cell equator.

B)

Sister chromatids line up at the cell equator.

C)

Each chromosome consists of two sister chromatids.

D)

Four nuclei start to form around the chromosomes.

E)

Sister chromatids are pulled apart at the centromeres.

F)

The chromosome number is reduced from 2n to n.

G)

Crossing over can occur during synapsis.

H)

The chromosome number remains the same from n to n.

Answer 1

Meiosis is a type of cell division that produced haploid daughter cells from diploid parental cells. One diploid cell forms four haploid daughter cells. It has two phases:

1. Meiosis-I: In this phase, crossing over takes place between the homologous chromosomes for genetic diversity.

2. Meiosis-II: It is similar to mitosis.

Let's consider the given characteristics for Meiosis-II:

A) In meiosis-II, homologous chromosomes have no role to play. Homologous chromosomes are present in meiosis-I.

B) Sister chromatids line up at the center in metaphase-II stage forming metaphase stage. Hence, this is characteristic of meiosis-II.

C) This is also the characteristic as each chromosome has two chromatids which are genetically identical therefore called sister chromatids.

D) In telophase-II, the nuclear membrane starts to form. Thus, resulting in four nuclei formation. So, this is the characteristic of meiosis-II.

E) In anaphase-II, the sister chromatids are pulled towards the pole while the spindle fiber shortens. Therefore, it is a characteristic of meiosis-II.

F) This is the characteristic of meiosis-I as the chromosome number decreases with the separation of homologous chromosomes.

G) Crossing over occurs in prophase-I so it is not a characteristic of meiosis-II.

H) This is the characteristic of meiosis-II as meiosis-II is similar to mitosis. The cells formed will have same chromosome number as separation of sister chromatids takes place.

Hence, the characteristic of meiosis-II from the above given are: B, C, D, E and H.