The cell cycle Flashcards
What are the three phases of the cell cycle
Interphase
Mitosis
Cytokenisis
What are the name of the chemical signals which trigger each phase
Cyclins
What are the three phases interphase consists of
G1
S
G2
What is G0.
Why do cells enter g0
G0-a resting phase triggerent during early g1
cells may go into g0 to differentiate
senescence- cell no longer candivide, or cell doesnt need to divide and enter mitosis
apoptosis- cell death
How long do cells stay in the g0 phase
Some cells are in there for a long time
Some dont leave
what does senescent mean
Cells can no longer divide
What is apoptosis
Programmed cell death
What are the checkpoints used in G1
Checks for DNA damage before cell DNA is sent to S phase and is replicated
(checks if cell is ready to enter s phase)
What happens to the cell in g1
cell increases in size
transcription of genes to make RNA
duplicates organelles
Biosynthesis- synthesising enzymes and proteins needed for s phase.
what is the name of the gene which helps control the g1 phase
P53 (tumour supressor)
What events happen in s phase (interphase)
Replication of DNA- each chromosome
How does the speed of the s phase helps DNA avoid mutations
The exposed DNA bases are susceptible to mutations, the speed of this phase avoids the chances of this happening
What is the name of the genes replicated first in s phase
Housekeeping genes
What type of gene is usually replicated last in s phase
Inactive genes are usually replicated last.
What is a gene
A segment of DNA containing sets of instructions on how to make specific proteins
