Unit 6 - Cell Division Flashcards
What is the cell cycle?
A highly ordered sequence of events which takes place in a cell, resulting in the cell’s division.
What are the two main phases of the cell cycle?
- interphase
- mitotic division phase
What is interphase?
The period of cell growth before cell division when the cell is working normally.
What are the three parts of interphase?
G1, S and G2.
What happens in G1?
G1 is the first growth phase - the cellular components are duplicated and cells increase in size.
What happens in S phase?
S is the synthesis phase - when DNA is replicated in the nucleus.
What happens in G2?
G2 is the second growth phase - when further growth occurs and the duplicated chromosomes are checked for errors.
What are the two parts of the mitotic division phase?
Mitosis and cytokinesis.
What is G0?
When a cell leaves the cell cycle.
Why can cells leave the cell cycle?
- if the cell has become specialised
- if the DNA has been damaged
What are senescent cells?
Senescent = too old to continue replicating
Where are the three checkpoints in the cell cycle?
- G1
- G2
- In mitosis
What does the G1 checkpoint verify?
- The cell is the right size
- There are the right number of organelles
- There is no major damage to DNA
What does the G2 checkpoint verify?
That DNA replication has occurred correctly.
What does the checkpoint in mitosis verify and where is it?
The checkpoint is during metaphase and checks that chromosomes have correctly aligned and attached to the spindles.
