NEET Important Questions for Cell Cycle and Cell Divisions
FAQs on NEET Cell Cycle and Cell Divisions Important Questions with Solutions
1. Explain the Cell Cycle.
Cell Cycle Consists of AND replication and cell division. All the processes and events that take place in the cell cycle are controlled genetically. The duration of the cell cycle varies in different organisms and it also depends on the type of cells. If we talk about the human cell cycle then in an average manner, a human cell cycle lasts up to 24 hours. The yeast cell cycle takes only ninety minutes to complete. The cell cycle is always divided into the M phase and Interphase. In interphase cell growth and replication of DNA takes place, interphase takes 95% time of the whole cell cycle. In the M phase, the cell division takes place known as Mitosis.
2. What is mitosis?
Mitosis generally happens in diploid somatic cells of beings ( animals ) though there are some exceptions like the haploid male drone of honey bees. If we talk about plants then mitosis takes place in both diploid and haploid cells. It is mitosis that is responsible for the genetic continuity, growth, and repair of multicellular organisms. Seeing this process in humans, we can state that the epithelial lining, lining of the gut and also the blood cells are replaced in a continuous manner. In the plants, it is meristematic tissues that divide continuously all their life.
Mitosis is accountable for asexual reproduction and vegetative reproduction. Karyokinesis occurs in 4 parts:
Prophase
Metaphase
Anaphase
Telophase
3. What do you understand by prophase, metaphase and anaphase?
We will discuss all three of them separately
Prophase
Chromosomes are not tangled but are condensed. The two chromatids attached to the centromere are visible in this process. All the duplicated centrosomes radiate asters ( microtubules ). Apparatus that is Mitotic consists of spindle fibres and also asters ( microtubule ). In this process, Golgi bodies, endoplasmic reticulum, etc disappear.
Metaphase
In this process, the complete disintegration of the nuclear force happens. The two sister chromatids are attached by the centromere that is attached by centromere which is aligned at the equator. Each chromatid is attracted to the spindle fibres.
Anaphase
In this phase, the centromere splits and the two sister chromatids separate and go to different poles.
4. What is cytokinesis?
In this process separation of cytoplasm happens. This separation takes place after the two nuclei are being formed. After this, the cell organelles are distributed between the daughter cells. In some beings like algae, fungi and plant cells, the process of cytokinesis is not immediately followed by karyokinesis. The stage followed by is known as a syncytium. Examples are liquid endosperm in coconut, coenocytic hyphae of Rhizopus, etc.
5. What is meant by Interphase?
Interphase is the process that takes between two successive M phases of the cell division. Interphase is divided into three phases:
GAP 1
This is the gap between mitosis and DNA replication of the next cycle of cell
Synthesis
DNA replication takes place in this process. The content of DNA cells doubles and duplication of centriole happens. Chromosome numbers remain the same.
GAP 2
The cells continue to grow and get prepared for mitosis. In this process protein synthesis also takes place.