Cell Cycle

Question 1

G-zero

Answer 1

Resting phase, no division

Question 2

G-1

Answer 2

“Gap 1”

Cells increase in size

Question 3

S phase

Answer 3

Synthesis

DNA replication

Question 4

G-2

Answer 4

“Gap 2”

More growth

Question 5

M phase

Answer 5

Mitosis

Cells divide

Question 6

G1 to S checkpoint

Answer 6

Commits to cell cycle

Should DNA be replicated?

Question 7

G2 to M checkpoint

Answer 7

Checks DNA has been replicated correctly

Question 8

MPF

Answer 8

Mitosis promoting factor

Something in cytosol regulating cell cycle

Question 9

Cyclin

Answer 9

When low, MPF kinase is inactive

When high, kinase is activated, cell enters M phase

Regulates the activity of cdk (cdc2)

Forms a complex with cdc2, active

Question 10

Cdks

Answer 10

Cyclin-dependent kinases

MOF-like enzymes

Example: cdc2

Only active when bound to cyclin!

Question 11

CAK

Answer 11

Cdk-activating kinase

Phosphorylates cdc2/cyclin complex

Question 12

Wee1

Answer 12

Protein kinase
Phosphorylates tyr15

Inhibits cell cycle

Question 13

SCF

Answer 13

E3 ligase

Degrades G1 cyclins

Question 14

APC

Answer 14

Anaphase promoting complex

E3 ligase

Targets proteins for degradation vis ubiquitin tags

APC/cdc20 - degrades securin so chromatids separate

APC/cdh-1 - degrades mitotic cyclins

Question 15

ATM

Answer 15

Checks DNA for damage, DSBs

Activates chk2, which activates p53

Question 16

Chk2

Answer 16

Checkpoint kinase 2

Works in G1

Activated by ATM if there is DNA damage

Phosphorylates/activates p53

Question 17

P53

Answer 17

Tumor suppressor

Unstable unless phosphorylated

Transcription factor, activates transcription of p21, which binds to cdk and arrests cell cycle

Question 18

Histologic grade

Answer 18

How many cells look normal?

Question 19

Nuclear grade

Answer 19

Size and shape of nucleus?

DNA-aneuploidy?

Question 20

Replication grade

Answer 20

How many cells actively dividing?

Question 21

Antimetabolites

Answer 21

Methotrexate

Look like DNA bases, causes DNA damage

Fix it apoptosis

Prevents dna from being replicated

Question 22

Alkylating agents

Answer 22

Look like DNA bases

Cause inter strand cross linking

Two strands can’t be pulled apart

No dna synthesis, no cell division

Question 23

Microtubule inhibitors

Answer 23

Plant derived

Prevent cell from pulling apart chromatids during anaphase

Can’t replicate

Question 24

Topoisomerase inhibitors

Answer 24

Bind to DNA, prevent topoisomerase from unwinding dna

Antibiotics

Question 25

Monoclonal antibodies

Answer 25

Targeted treatment

Question 26

Hormone receptor

Answer 26

Targeted

Question 27

Targeted cancer treatments

Answer 27

Receptor inhibitors
Inhibit specific proteins/pathways
Inhibition of angiogenesis

Question 28

Hormone receptor treatment

Answer 28

Cancer cells grow more hormone receptors, increase growth signals

Tamoxifen binds to receptor, prevents signal

Question 29

HER2 receptor

Answer 29

Human epidermal growth factor receptor

Found in normal breast tissue

Sometimes gene overexpresses or duplicates
-more HER2 protein, more cell growth

Question 30

Trastuzumab

Answer 30

Monoclonal antibody

Targets HER2 receptors, blocks signal

Question 31

Inhibition of angiogenesis

Answer 31

Angiostatin, endostatin, thrombospondin are proteins that stimulate angiogenesis

Block those, conjugate antibody to deliver it to tumor, inject into tumor