Cell Cycle

[azarbock]

I am having a hard time finding information on the cell cycle for a somatic animal cell. Can anyone give me a brief outline of the stages involved and explain what a dyad is? Thanks for any help!

[asutoshsahu]

You mean somatic cells , the cells which are not involved in reproduction
they replicate by mitotic division
it is carried out by main to phases.
a. Karyokinesis or division of nucleus
b. Cytokinesis or division of cytoplasm

a. Karyokinesis
It involves four stages.
1. Prophase - Nuclear membrane and nucleolus disintegrates and centrosome divides to give to centriole on two poles. It forms spindle fibres on both the poles
2. Metaphase - In this phase the chromosomes come to the equatorial plane and the spindle fibre get attached to the centromere
3. Anaphase - In this phase the spindle fibre contracts and the chromosome divides from center and become v-shaped and go near the centriole
4. Telophase - the half of the chromosome i.e. the no equal to the mother cell get accomodated in the two ends and the nuclear membratne and nucleolus form around it.
At this stage the no. of chromosome become double of the previous mother cell.

b. Cytokinesis

The Plasm membrane contract on the middle portion and the cytoplasm divide into two parts by clevage furrow.


Please send reply regarding this and tell me about any doubt.

[victor]

No interphase? G1, S, G2?

[azarbock]

Where do the G1, S, and G2 phases occur in the cycle? I have written that G1 is the growth stage of anaphase before DNA duplication (the S phase is DNA synthesis) and the G2 phase is the growth stage of anaphase after DNA duplication.

I guess my question would be: is G1, S, and G2 phases of anaphase? I thought DNA replication occured in Interphase?

[MrMistery]

G1, S and G2 are stages of interphase

[azarbock]

Thank you to everyone for all the help - I think I've got it now!

[sdekivit]

no signaltransduction routes that regulate the going from G1 --> S and from S--> G2 with specific kinases ? (MAPk for example) regulation of gene expression ? there so much you can tell about the cell cycle.

[MrMistery]

Not everyone studies cell bio at the level you do sdekivit. Some study it for school tests. And for that, what was said is enough..

[asutoshsahu]

Hey azerbock and every one I have only written in brief to explain the cell cycle . It is for the school level only.
So I thought there is no need to explain the G1, S & G2 phases.

[lara]

well,apart from schools, are there kinases involved?can anyone xplain?

[sdekivit]

well,apart from schools, are there kinases involved?can anyone xplain?

search in the literature for specific cyclin dependant kinases, CDKs

[Morris]

Yes there are some CDKs that regulate cell cicle, infact after every phase there is a checkpoint where is controlled if the cell is ready to go to next checkpoint. Infact failure iof that controls cen bring at tumorigenesis or cell death.