Question

In telophase of mitosis
A. Chromosomes get arranged in middle of cell
B. Chromosomes fibres become clear
C. Chromosomes aggregate at opposite poles to form daughter nuclei
D. Nuclear envelope disappears

Answer 1

Mitosis is a part of the cell cycle in which the nuclear material undergoes division. It generally takes place in the eukaryotic cell.

Complete answer:
The process in which the nucleus of a eukaryotic cell divides equally into two daughter cells is called mitosis. During mitosis, one cell gives two identical cells in a single phase.The process of mitosis is divided into five phases namely- interphase, prophase, metaphase, anaphase and telophase.

Interphase – Interphase stage is also called the resting phase or preparatory phase. During this phase, the genetic material i.eDNA in the cell is copied in the preparation of cell division that results in the formation of two identical complete sets of chromosomes. Two centromeres are present outside the nuclear core that contain a pair of centrioles. Synthesis of new molecules and organelles takes place during this phase.

(1) Prophase- The chromosomes undergo condensation to form X-shaped structures. Each chromosome consists of sister chromatids and they contain exactly identical information. Nucleus and cytoplasm undergo changes. The chromatin fibres arrange more tightly and are folded, nucleoli disappear at this stage. Each duplicated chromosome appears to be two identical sister chromatids.
(2) Metaphase- The chromosomes move to the equator of the cell. The centrioles from the opposite poles of the cell with the spindle fibres extend towards them. The attachment of spindle fibres attached to the sister chromatids takes place.
(3) Anaphase- The sister chromatids start moving towards two opposite poles.
(4) Telophase- A membrane formation around each set of chromosomes takes place. At each pole a cell with a complete set of chromosomes are formed. The spindle fibres during this phase shorten, the kinetochores separate and the chromatids are pulled apart and start moving towards poles. The daughter chromosomes that move them apart start disappearing and become clear.

Therefore, from the above explanation the correct answer is option (B) Chromosomes fibres become clear.

Note: Mitosis aims at growth and replacement of damaged or worn out cells. Mitosis is a mean of asexual reproduction as during this phase of cell division the daughter cells formed are exactly identical to parent cell. Meiosis is a mean of sexual reproduction in which the sex cells undergo reduction in number to form gametes with half number of chromosomes.