Cell Cycle and cancer

Question 1

Prophase facts

Answer 1

Initiates mitosis
Gradual condensation of chromosomes
Disintegration and eventual disappearance of the nucleolus
Formation of mitotic spindle
Centrosomes move towards poles

Question 2

Cyclin (regulatory subunit) and CDK (catalytic subunit) for each checkpoint

Answer 2

M: cyclin B, CDK 1
G1: Cyclin D, CDK 4/6
S: Cyclin A, CDK 2

Question 3

Two main groups of CDK inhibitors

Answer 3

INK4 proteins (INhibit cdK4): affects CDK4/6.
p16, p15, p18, p19

cip/kip proteins: affects CDK 1/2
p21***, p27, p57

protein suppress the formation of tumors (tumor suppressor proteins)^^^^^.

Question 4

Tumor Suppressor Genes

Answer 4

Retinoblastoma (Rb)

p53. p53 activates p21 to halt cell cycle.

p53 = guardian of genome. When it is mutated, cancer occurs.

Question 5

Pathways leading to apoptosis

Answer 5

Extrinsic pathway: signal binds to cell surface receptors-death receptors (DRs)

Intrinsic pathway: Involves dmg to nuclear DNA as well as mitochondria. Triggered by agents such as ROS.

Question 6

Hall marks of Cancer