Question

Give a description of the 2N phase of the cell cycle and explain how crucial it is in reference to cell growth and cell survival.

Answer 1

One of the most important thing iN living organism is cell division. The replication of dna along with cell growth takes place in the cell division, which is necessary to normal body function.

The cell cycle is nothing but wherein the cell division, dna replication and cell growth takes place in a sequential order, which atlast divides into two daughter cells.

It is to be noted that dna synthesis occurs only in one specific stage, while cell growth is a continous process.

The 2n process is the meiosis process. wherein the chromosomes takes centrestage. the first stage is the interphase stage wherein the dna are copied. in the next stage the prophase stage the chromosomes from male and female are involved in synapsis (crossing over). Here the parts of the chromosomes are swapped. This gives us variation in the new chromosome. the next stage is metaphase, wherein the chromosomes are independently oriented, this gives variation. During metaphase I chromosomes are clumped together, while in anaphase I they are pulled back. During telophase I the nuclei are reformed. Then these cells are divided by the process of cytokinesis. IN Prophase II there is no crossing over again, but what happens is that the chromosomes line up together in the middle and the centromeres (region of the chromosomes wherein microtubules of the spindle attach) are going to get attached to the spindles. in anaphase II the chromosomes are pulled to other side. in telophase II and cytokinesis we get the four cells , and each of these cells has two chromosomes.

The next step is that these chromosomes will fertilise and a new organism would be formed.

Meiosis is the mechanism by which conservation of specific chromosome number of each species is achieved across generations in sexually reproducing organisms. It also increases the genetic variability in the population of organisms from one generation to the next. Variations are very important for the process of evolution. Without variation there woul be no species diversity, which would lead to extinction. Also productivity increases with species diversity. The crossing over in the prophase 1 helps in the genetic recombination process.

Without this process there will be no cell growth and the cell survival would be in danger.