Given graphs P,Q,R and S show four stages of cell cycle i.e., `G_(1)`,S,`G_(2)` and M, but in random order. Identify the stages and match with the activites of the cell.
I. Taxl ol treatment, which prevent microtubule depolymerization, arrests the cell at this tage .
II. With a mitogen treatment , such as an epidemal growth factor, an arrested cell at this stage proceeds to the next stage of the cell cycle.
III. The cell cycle check point at this stage confirms. that DNA duplication is complete before the cell proceeds to the next stage

Options

A. I-R,II-Q,III-R
B. I-Q,II-S,III-R
C. I-R,II-Q,III-S
D. I-P,II-S,III-Q

Answer

A

Explanation

The given graphs P,Q R and S illustrate the cell stages as folowing:
P-M-phase showing reduction in DNA content from 4C to 2C, Q-`G_(1)-`phase, the amount of DNA is 2C,R-`G_(2)-`phase, the amount of DNA has doubled after S-phase i.e., 4C, S-S-phase, showing duplication of DNA content.
Taxol treatement prevetns microtubule depolymerisation at 'M-phase'. Cell growth is assessed at `G_(1)`. checkpoint, if conditions are favourable for division, the cell begins to copy its DNA, initiating S-phase of else the cell cycle will get arrested in `G_(0)` phase. This `G_(1)` checkpoint is regulated by mitogens which affect cycle is -CDK complexes which further perform checkpoint mechasism. The second checkpoint lies between `G_(2)` and M. When the duplication is complete, Mitogen promoting factors (MPF) triggers the start the start of M phase. If this checkpoint in passed, the cell initiates the many molecular processes that signal the beginnning of mitoisis.