The cell cycle (a,b) Flashcards
What is the cell cycle?
The highly ordered sequence of events that take place within a call, resulting in the division of the nucleus and the formation of 2 genetically identical daughter cells.
What is interphase?
Growth period of the cell cycle, between cell divisions (mitotic phase). Consists of phases G1, S and G2.
Describe gap phase 1
Proteins are synthesised + produced + organelles replicate. Cell increases in size.
Describe synthesis phase
DNA is replicated in the nucleus.
Describe gap phase 2
Cell keeps growing, energy stores are increased + duplicated DNA is checked for errors.
What happens during interphase? (generally)
- DNA is replicated and checked for errors
- Protein synthesis
- Mitochondria grow and divide
- Chloroplasts grow and divide
- Normal metabolic processes occur
What occurs in the mitotic phase?
The period of cell division: mitosis and cytokinesis
What is G0?
G0 is the name given to the phase when the cell leaves the cell cycle either temporarily or permanently. Can happen for cell differentiation, or if the cell DNA is damaged.
How is the cell cycle regulated?
Checkpoints control mechanisms of the cell cycle. They monitor + verify whether the processes at each phase of the cell cycle have been accurately completed before the cell is allowed to progress into the next phase.
Describe the G1 checkpoint
Triggers DNA replication if the cell satisfies requirements - cell size, nutrients, growth factors + DNA damage - otherwise it enters a resting state - G0.
Describe the G2 checkpoint
Checks for cell size, DNA replication, DNA damage. If passed, the cell initiates the molecular processes that signal the start of mitosis.
Describe the spindle assembly checkpoint/metaphase checkpoint
(in mitosis) Where all chromosomes should be attached to spindles + have aligned. Mitosis cannot proceed until the checkpoint is passed.
