Cell Cycle Flashcards
What is cell cycle and it’s stages
Regular sequence to produce new cells
has four stages interphase( G1 , S and G2 ) and mitosis
G1 description
It is the stage after mitosis
long stage of active RNA and protein synthesis (that controls cell Cycle and are used in DNA replication )
volume of sales returns to normal size after halved by mitosis
accumulation of enzymes in nucleotides for DNA synthesis
time between mitosis in DNA replication
S phase description
It is the stage after G1 but before G2
the stage of DNA replication and histone synthesis and centrosome duplication
G2 description
It is a relatively short phase after synthesis but before mitosis proteins for my mitosis are accumulated and mitosis is prepared during this stage
Mitosis and it’s stages
This is the stage of actual cell division is divided into four stages prophase metaphase anaphase telophase
How does G0 occurs and mitigation
Post mitotix cells differentiate and cell cycle is suspended entering stage Called G0
cell cycle can be renewed example in liver cells by mitogen growth factors from extra cellular environment that trigger release of kinase signaling in cells
Cells then maintained at restriction point at the G1/S boundary until sufficient nutrients and enzymes for synthesis or accumulated
Restriction point
These are stages during cell division which won’t initiate progression to next stage and to proceed in activities are done
G1 / S boundary
DNA replication is prepared and we enter S phase IF all DNA is intact all enzymes in nutrients in micro environment are present
G2 / mitosis boundary
Prepare to enter my ptosis if all DNA is completely replicated
Metaphase/ Anaphase restriction point
Begin chromatids separation and prepare for cytokinesis if all DNA is intact and all chromosomes are attached to mitotic spindle
What regulates cell cycle and how they do it
Cycline activate cyclin-dependant kinase which activate enzymes and proteins for a specify stage
What happens to cyclins after stage is done
-cyclins ubiquitinated and degraded
What halts progression of cycle and outcome if can’t be fixed
- insufficient nutrients
- damage in DNA
- non-conducive extra cellular environments
-tumor suppressor gene encodes proteins guide cell to apoptosis
Restriction point and boundary regulators and the proteins they target
G1 : cyclin D -CDK4 / RB protein ( releasing E2F transcription factors which active genes for G1 and cyclin A )
G1 / S : cyclin E - CDK2 / further activation of E2F
S phase : cyclin A - CDK2 / DNA polymerase and dna synthesis proteins
G2/M : cyclin A - CDK1 / cyclin B
Mitosis stage : cyclin B - CDK1 / nuclear lamins , histone H1 , chromatin and centrosome proteins.
