Question

Which of the following phases during mitosis, ER, and nucleolus begin to disappear?
(a)Early prophase
(b)Late prophase
(c)Early metaphase
(d)Late metaphase

Answer 1

It occurs during the first stage of mitosis. Mitosis occurred during the cleavage division. Cleavage involves cytokinesis and karyokinesis (mitosis) together. Mitotic apparatus consists of a central spindle and the polar esters which are made up of polymers of tubulin protein known as microtubules. They are nucleated by centrosomes.

Complete answer:
The ER and nucleolus begin to disappear during the late prophase during mitosis. The stage which occurs in both mitosis and meiosis is the prophase of cell division. The disruption of the nuclear envelope marks the beginning of a late professor in which the nuclear membrane is broken down into small membrane vesicles that closely resembled the endoplasmic reticulum and remain visible around the mitotic spindle. The chromosome starts condensing continuously and shortens and thickens until they completely form the units which will undergo mitosis. The nucleolus stars disappear during late prophase and the mitotic spindle microtubules are free to enter the nuclear region where the formation of specialized protein complexes known as kinetochores big in on each Centromere. They get attached to the spindle microtubules that are known as kinetochore microtubules and others are known as polar microtubules which help in the formation and maintenance of the spindle structure with Astral microtubules that remain outside the spindle.

Additional information:
Early prophase: The nuclear chromatin starts becoming organized and condenses into thick strands which eventually become chromosomes. The cytoskeleton disassembles and the components of the mitotic apparatus begin to form the nucleus at the opposite end of the cell known as the mitotic spindle.
Early metaphase: The cell cycle of all genetic material gets condensed into chromosomes which become visible. The nucleus disappears during this stage and the chromosome appears in the cytoplasm of the cell whose continent is the cell partition into the daughter cells.
Late metaphase: The chromosomes get aligned on the metaphase plate and the sister chromatid breaks apart after the meiotic spindle checkpoint is passed. the continent their division until the four cells are produced and each cell has one allele per gene.

So, the correct answer is ‘Late Prophase’.

Note: The process of mitosis was first observed by Strasburger in animal cells and further coined by Fleming. The process of meiosis was coined by Farmer and Moore. The interphase stage occurs in both meiosis and mitosis. The process is divided into meiosis 1 and meiosis 2. Meiosis-1 is further divided into four phases which are professor metaphase anaphase and telophase.