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Cell cycle
Appears in
Concepts tested here
- DNA content after S phase
- DNA content in cell cycle
- Phases of the cell cycle
- S phase
All Questions
2015 AIPMT-I 1 question
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A somatic cell that has just completed the S phase of its cell cycle, as compared to gamete of the same species, hasA somatic cell is diploid (2n, 2C) and a gamete is haploid (n, C).
After S phase the DNA doubles to 4C, but the chromosome number stays 2n.
So compared with a gamete, it has twice the chromosomes and four times the DNA.
2014 AIPMT 2 questions
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During which phase(s) of cell cycle, amount of DNA in a cell remains at 4C level if the initial amount is denoted as 2C?DNA replicates in S phase, raising the content from 2C to 4C.
It stays at 4C through $G_2$ and M phase until the chromatids separate and the cell divides. -
In 'S' phase of the cell cycle:S (synthesis) phase is when DNA replication takes place. The amount of DNA per cell doubles, but the chromosome number does not change.
2009 AIPMT 1 question
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Given below is a schematic break-up of the phases/stages of cell cycle:
Which one of the following is the correct indication of the stage/phase in the cell cycle?The cell cycle consists of interphase ($G_1$, S and $G_2$ phases) and the M phase (mitosis: prophase, metaphase, anaphase, telophase, followed by cytokinesis).
In the diagram the long arc of interphase is divided into $G_1$, a middle phase labelled D, and $G_2$.
The phase between $G_1$ and $G_2$ is the S or synthetic phase, in which DNA replication takes place and the amount of DNA per cell doubles (2C to 4C).
So D is correctly identified as the synthetic phase.
The labels A, B and C fall within the M phase, but they are not correctly named in the other options (for example, karyokinesis is the whole process of nuclear division, not one sub-stage, and cytokinesis follows the last stage of mitosis).
Hence the correct indication is D – synthetic phase.