cell cycle
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explain the what happens to cohesins when microtubules bind to centromeres
cyclins break down along the length of the chromosome apart from at the centromere these cohesins break down last to prevent aneuploidy
name some cohesinopathies
Roberts syndrome Conerlia de Lange syndrome Non-disjunction of chromosomes
what are CDKs?
cyclin dependent kinases - regulate progression of the cell cycle
what activates CDKs?
cyclins
what does the retinoblastoma protein do?
inhibits E2F proteins by binding to them stops cells from going past G1 into S phase
what happens when Cdk2 is activated?
inactivates Rb by phosphorylation so E2F is released so the cell can enter S phase
explain the role of p53 in controlling the progression of the cell cycle
p53 is a transcription factor binds to the gene for p21 p21 controls whether or not cyclin-Cdk2 can activate E2F by phosphorylating Rb
how does the mutation of the RB1 protein lead to cancer?
mutation means no functional Rb no Rb binds to E2F E2F doesnt stop cell from entering S phase uncontrolled proliferation –> cancer
what are the three cell cycle checkpoints?
end of G1 G2-M transition Mitosis (metaphase)
what happens at the end of G1 checkpoint?
checks cell size, growth factors and DNA damage controlled by p16 which inhibits CDK 4/6 so it cant interact with cyclin D
what happens in the G2-M checkpoint?
checks DNA replication, damage and cell size stops cell cycle if there’s damage
what happens in the mitosis checkpoint?
checks that the chromosomes are attached to the spindles
what are the three main types of chemotherapy?
anti-mitotics biologics antihormonal drugs
what are the two classes of anti-mitotics?
vinca-alkaloids taxanes
what do vinca alkaloids do?
prevent microtubule formation metaphase cannot occur
what do taxanes do?
prevent the microtubule disassembly cells cant enter telophase
what are biologics?
monoclonal antibodies
when are anti-hormonal chemotherapies used for?
hormone driven cancers caused by overexpression of a receptor or sensitive to a hormone
what stages form interphase?
g1 s g2
what happens during G1 and G2?
no DNA synthesis environment is monitored
what happens in G1?
Monitors internal and external environmental conditions to ensure it is suitable for mitosis.
what happens in G2?
double checks DNA has been copied properly. Any mistakes are repaired, if they are unable to be repaired the cell undergoes apoptosis
what happens in S phase?
DNA replication 2n to 4n
what are the stages of mitosis?
o Prophase o Metaphase o Anaphase o Telophase o Cytokinesis