224k views
3 votes
Generally, in a given organism, the S, G2, and M phases of

the cell cycle take a defined and stereotyped amount of time in most cells.
A. True
B. False

1 Answer

7 votes

Final answer:

The statement regarding the S, G2, and M phases of the cell cycle is false; the duration of these phases can vary among different cell types and conditions, and cells can enter a resting G0 phase where they stop dividing.

Step-by-step explanation:

The statement is false. Although the S (Synthesis), G2 (Second Gap), and M (Mitotic) phases of the cell cycle generally occur in an orderly sequence, the actual duration of these phases can vary among different cell types and under different conditions. For example, the S phase typically lasts between 8-10 hours and the G2 phase approximately 5 hours, while the M phase is much shorter, usually lasting about 0.5 hours in rapidly dividing human cells with a 24-hour cell cycle. However, the duration of phases can be influenced by factors such as cell type, organism, and whether the cells are in culture or part of a living organism. Therefore, the time spent in each phase is not always stereotyped and can exhibit variation.

Certain cells can also enter a resting state called the G0 phase, where they temporarily or permanently cease dividing. This phase represents a condition where the cells are not actively progressing through the typical cell cycle, further supporting the notion that the cell cycle phases can have variable lengths.

User Dodecaplex
by
8.4k points