The cell cycle Flashcards
What is required to prevent the introduction of serious errors during cell number expansion?
Coordination mechanism
What are the 3 critical events that need to occur during the cell cycle?
- Chromosome replication
- Chromosome segregation
- Cell division
What do almost all normal cells require in order to proliferate?
Extrinsic factors
What type of proteins can overrule stimulatory factors & force proliferation to a halt?
Signalling proteins
What is the master governor that makes the major decisions regarding the cell fate?
Cell cycle clock (operates in the nucleus)
What are the 2 process that the cell cycle clock can encourage?
Division or the prevention of replication (sent into G0 or quiescent state)
What are the 5 stages of the cell cycle?
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
What occurs during prophase?
movement of the centrioles to polar end of the nucleus, condensation of chromosomes
What occurs during prometaphase?
components of the mitotically spindle elongate away from the spindle poles
What occurs during metaphase?
chromosome alignment is complete
What occurs during anaphase?
pairs of sister chromatids are separated
What occurs during telophase?
chromosomes start to de-condense, nuclear membrane starts to be re-established.
When is chromatin de-condensed?
when the cell is not dividing (de-condenses after telophase)
Describe the parts of interphase
G1, S (synthesis phase), G2, M (mitotic phase)
What occurs during G1?
- cell increases in size
- ribosomes, RNA produced
- preparation for DNA synthesis
- where the cell responds to signals
What occurs during the S stage?
DNA synthesised (chromosome duplicated)