The cell cycle Flashcards
what is the cell cycle
the production of 2 daughter cells
in what kind of tissues does the cell cycle last longer
adult
what happens to cells in vitro
they divide continuously at regular intervals
what happens at mitosis
2 daughter cells formed and after a while each cell will then undergo mitosis again
what are cycling cells
cells that continue to divide regularly in definite intervals
what is a cyclin
a family of proteins whose conc increases and decreases throughout the cycle
what are the cell cycle protein molecules
cyclins A,B and E
what do cyclins activate
CDKs
what happens once the cell cycle has completed
cyclins and CDKs are degraded
what is Interphase
an interval between the end of mitosis and beginning of the next where the DNA is duplicated
what is the S phase
a period in which the new DNA is synthesised
s phase =
synthesis
what promotes the S phase
cyclin A and CDKs
what happens if the cell cycle is not completed
cell cycle arrest occurs
what does DNA damage during DNA replication cause
- Deoxynucleotide incorporation error during replication
- By spontaneous deamination of bases during normal genetic functions
- From x-radiation that cause “nicks” in the DNA
- From UV irradiation
- From various chemicals that interact with DNA.
In what phase does DNA replication take place
during the S phase
what does defects in repair mechanisms cause
disease
name the disorders caused from defective DNA repairing
- Xeroderma Pigmentosum
- Homologous recombination (HR)
- Hereditary Nonpolyposis Colon Cancer (HNPCC)
what is the G1 phase
end mitosis beginning S
controlled by cyclin E and CDKs
what cells are present in the G0 phase
cells that retain the capacity for proliferation but are no longer dividing - they do not enter the s phase
quiescent
cells in G0 phase
what takes place during G2
the cell prepares for division, this period ends with the breakdown of the nuclear membrane and the onset of chromosome condensation
what controls the G2 phase
cyclin B and CDKs
explain interphase
individual chromosomes not visible
uncoiled into very long narrow structures
