Cellular structure which always disappears during mitosis and meiosis isa)Plastidsb)Nucleolus and nuclear envelopec)Plasma membraned)None of the aboveCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

Explanation:The correct answer is B: Nucleolus and nuclear envelope. During mitosis and meiosis, the cellular structure that always disappears is the nucleolus and nuclear envelope. This is because these structures need to break down to allow the chromosomes to separate and be distributed to the new cells formed during cell division.Here's a brief overview of their roles and what happens during cell division:Nucleolus:- It is a small, dense structure within the nucleus of a cell.- Its primary function is to produce ribosomes, which are essential for protein synthesis.- During the prophase of mitosis and meiosis, the nucleolus disassembles, and its components are dispersed throughout the cell.Nuclear envelope:- It is a double membrane that surrounds the nucleus of a cell.- It separates the genetic material within the nucleus from the cytoplasm of the cell.- During the prophase of mitosis and meiosis, the nuclear envelope breaks down, allowing the chromosomes to be accessed by the spindle fibers that will separate them during cell division.In summary, the nucleolus and nuclear envelope are cellular structures that always disappear during mitosis and meiosis to facilitate the process of cell division.

Answer

Nucleus and nucleolus disappear because the genetic material i.e. DNA will also have to divide in S phase that will facilitate the further divison..

Answer

Explanation:
During both mitosis and meiosis, the nucleolus and nuclear envelope disappear. Let's discuss why this happens in detail.

Nucleolus:
The nucleolus is a distinct structure within the nucleus of a cell. It is responsible for the production and assembly of ribosomes, which are essential for protein synthesis. During cell division, the nucleolus disappears to ensure the accurate distribution of genetic material to the daughter cells. This disappearance is due to the breakdown of the nucleolus during prophase, the first stage of mitosis or meiosis.

Nuclear Envelope:
The nuclear envelope is a double membrane that surrounds the nucleus, separating it from the cytoplasm. It consists of an inner and outer membrane, with nuclear pores that allow the transport of molecules between the nucleus and the cytoplasm. During mitosis and meiosis, the nuclear envelope breaks down to facilitate the movement of chromosomes.

Mitosis:
Mitosis is the process of cell division that results in two genetically identical daughter cells. It consists of several stages: prophase, prometaphase, metaphase, anaphase, and telophase. During prophase, the nucleolus disappears, and the nuclear envelope breaks down. The chromosomes condense and become visible. In prometaphase, the spindle fibers attach to the chromosomes, and the nuclear envelope completely disintegrates. The chromosomes align at the equatorial plane during metaphase, and the sister chromatids separate and move towards opposite poles during anaphase. In telophase, the nuclear envelope reforms around the separated chromosomes, and the nucleolus reappears.

Meiosis:
Meiosis is a specialized form of cell division that produces gametes (sperm and eggs) with half the number of chromosomes as the parent cell. It consists of two rounds of division: meiosis I and meiosis II. Similar to mitosis, the nucleolus disappears, and the nuclear envelope breaks down during prophase I of meiosis. This is followed by the alignment and separation of homologous chromosomes during anaphase I. In meiosis II, the process is similar to mitosis, with the disappearance of the nucleolus and breakdown of the nuclear envelope during prophase II.

In summary, the nucleolus and nuclear envelope always disappear during mitosis and meiosis to ensure the proper distribution of genetic material and the formation of genetically identical or diverse daughter cells.

Answer

The cellular structure that disappears during mitosis is nuclear membrane and nucleolus. Mitosis maintains genetic similarity. The sequence of events is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are prophase, prometaphase, metaphase, anaphase, and telophase. During mitosis, the chromosomes, which have already duplicated, condense and attach to fibers that pull one copy of each chromosome to opposite sides of the cell. The cell then divides by cytokinesis to produce two genetically identical daughter cells.
So, the correct answer is c 'Nuclear membrane and nucleolus'.

Answer

This is because if the nuclear envelope and nucleolus disappear
it is easier for karyokinesis to take place
followed by cytokinesis that is why it disappears anyhow

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