Question

During mitosis, endoplasmic reticulum and nucleolus begin to disappear at which of the
following phase?
A) Early prophase
B) Late Prophase
C) Early metaphase
D) Late metaphase

Answer 1

Hint:- Mitosis is a type of cell division where a cell divides into two identical daughter cells (in which the total number of chromosomes is maintained). The mitosis cell division occurs for the growth and replacement of worn-out cells. The stages of mitosis include prophase, metaphase, anaphase, telophase.

Complete Answer:-
The first stage in both mitosis and meiosis of cell division is prophase. The two copies of the identical chromosomes are replicated forming sister chromatids during interphase. In the Early prophase, the mitotic spindle starts to form, and chromosomes start to condense, and the nucleolus disappears along with the endoplasmic reticulum and the nuclear envelope breaks down. The prophase is divided into early and late prophase. The late prophase is also called prometaphase. During the late prophase, the nuclear lamina disintegrates the nuclear envelope. The nucleolar breakdown results in the stoppage of the production of ribosomes which further leads to the endoplasmic reticular disintegration. The nucleolus can be observed clearly in this phase as the chromatin material is condensed and compact and the nucleolus disappears by the end of this stage and these are not observed in late prophase.
Thus, the right option is B.

Note:- The term mitosis was coined by Walther Flemming. Karyokinesis is another term coined by Schleicher and the term equational division was coined by August Weismann. The endoplasmic reticulum is a type of organelle made up of two subunits – rough endoplasmic reticulum, and smooth endoplasmic reticulum, a continuous membrane. It serves multiple functions and has an important role in the synthesis, folding, modification, and transport of proteins.