Tag: tissues of animals

The cell cycle mainly consists of 4 stages G$ _1$, S, G$ _2$, and M. The G$ _{0}$ phase also known as the extended G1 phase is a period in which the cell exits from the cell cycle. In this stage, the cell exists in a quiescent state and does not divide. Thus the correct answer is option A.

During the cell cycle, RNA and protein synthesis takes place during G$ _1$ and G$ _2$ phase. The cell cycle is an ordered set of events, culminating in cell growth and division into two daughter cells. Non-dividing cells not considered to be in the cell cycle. The stages are G$ _1$-S-G$ _2$-M.

G1 phase and the other subphases of the cell cycle may be affected by limiting growth factors such as nutrient supply, temperature, and room for growth. Sufficient nucleotides  and amino acids must be present in order to synthesize mRNA and proteins. Physiological temperatures are optimal for cell growth. In humans, the normal physiological temperature is around 37 C. Therefore, the correct answer is option D.

The cell cycle includes a series of events, that take place  in a cell which leads to the duplication of DNA and division of cells to form two daughter cells. This takes place in three different  periods and can be referred to as Interphase , Mitotic phase(M) and cytokinesis. While during the interphase or the initial phase, the cells grow in size and is ready for division, during the mitosis, the DNA starts duplicating, the nuclear membrane dissolves and the cells starts its division process to give rise to  two distinct daughter cells. Cytokinesis is the stage during which the two daughter cells are formed and separated.
So, the correct answer is option D.

One cell cycle of yeast is almost 90 minutes and a human cell takes almost 24 hours to divide by mitosis therefore by calculations it seems that a yeast can perform mitosis almost 16 times in the time of 1 division of a human cell.