2.6 Cell cycle (interphase) Flashcards
What phase does a cell spend most it’s time in?
Interphase
What are the long periods of growth called?
Interphase
What happens to the DNA during interphase?
It is replicated and checked for errors
What occurs in the cytoplasm during interphase?
Protein synthesis
What grows and divides during interphase?
- mitochondria
* chloroplasts (in plant and agal cells)
What else occurs in interphase?
Normal metabolic processes (cell respiration)
What are the 3 stages/phases of interphase?
- G1
- S
- G2
What is G1 and what occurs here?
- first growth phase
- organelles replicate
- cell increases in size
- proteins from which organelles are synthesised are produced
What is the S phase and what occurs here?
- synthesis phase
* DNA in the nucleus is replicated
What is G2 and what occurs here?
- second growth phase
- cell increases in size
- DNA checked for errors
- energy stores increased
What are the two main phases of the cell cycle?
- interphase
* mitotic phase
What happens after interphase?
The mitotic phase
What is G0?
The phase where the cell leaves the cycle (temporarily or permanently)
What reasons are there for the G0 phase?
- differentiation
- errors/ damaged DNA
- age
Why do cells enter the G0 phase due to differentiation?
• cells become specialised and can no longer divide and enter the cell cycle
Why does the cell enter the G0 phase due to DNA damage?
- a damaged cell can no longer divide
* enters a period of permanent arrest
Why do cells enter the G0 phase due to age?
- become senescent
* senescent cells are linked with age related diseases such as cancer and arthritis
What types of cells can be stimulated and return back to the cell cycle from the G0 phase?
Lymphocytes (white blood cells) in a immune response
What are checkpoints?
The control mechanisms of the cell cycle
What occurs at checkpoints?
Monitoring and verifying wether processes at each stage of the cell cycle have been accurately completed before cells progress to the next stage
What are the 3 checkpoints?
G1 checkpoint
G2 checkpoint
Spindle assembly point
What checks are made at the G1 checkpoint?
Check for cell size, Cell growth and DNA damage
What checks are made at the G2 checkpoint?
Checks for cell size, DNA replication and DNA damage
What checks are made at the spindle assembly point?
Checks that chromosomes are attached to spindles
