Question

The uncoiling of chromosome followed by formation of a nuclear membrane takes place in-
A. Interphase
B. Prophase
C. Metaphase
D. Anaphase
E. Telophase

Answer 1

Hint: The actively dividing eukaryotic cells pass through a chain/series of stages collectively known as the cell cycle. Meiosis and mitosis, two types of cell cycle are very well known. In mitosis, the genetic material or let's just say chromosome number remains the same from parent to daughter whereas in meiosis it gets reduced to half.

Complete answer:
>Prophase- Prophase occupies about over half of the mitosis. The nuclear membrane/envelope breaks down in order to form a number of small vesicles and the nucleolus further disintegrates. A structure called the centrosome starts to duplicate itself and form two daughter centrosomes that move to opposite ends of the cell. The centrosomes take care of the production of microtubules that will form the spindle fibres, constituting the mitotic spindle. The chromosomes further condense into very compact structures. Each of the replicated chromosomes can be seen to consist of two identical chromatids (referred as sister chromatids) and are held together by a structure known as the centromere.
>Metaphase- The chromosomes start aligning themselves along the metaphase plate of the spindle. apparatus.
>Anaphase- It is the shortest prevailing stage of mitosis. The centromeres here divide, and the sister chromatids of each chromosome start to pull apart i.e. move to the opposite ends of the cell, which are pulled by spindle fibres attached to the kinetochore regions. The separated sister chromatids are now called daughter chromosomes.
>Interphase- It is an intermediate phase where the cell gets prepared for activities.
>Telophase- It is the final stage of mitosis, and a reversal stage of most of the processes encountered during prophase. The nuclear membrane starts reforming around the chromosomes grouped at either pole of the cell, the chromosomes then uncoil and become diffuse, and the spindle fibres disappear.

Hence, the correct option is option E i.e. Telophase.

Note: All the alignment and the separation takes place in metaphase and in anaphase it is important to ensure that each daughter cell receives a copy of a single chromosome. There are several changes in the different phases before going in the cell cycle.