17D Assignment Flashcards
What are mitogens?
They are extracellular signals that stimulate cell division.
They are transcription factors that induce cell death.
They are kinases that inhibit cell proliferation.
They are produced by mitotic cells to keep nearby neighboring cells from dividing.
They are extracellular signals that stimulate cell division.
DNA damage induced checkpoint response in G1 ________________.
involves the inhibition of cyclin-Cdk complexes by p21.
causes cells to proceed through S phase more quickly.
involves the degradation of p53.
is activated by inhibition of ATM.
involves the inhibition of cyclin-Cdk complexes by p21.
UV exposure can cause DNA damage. Which of the following would you NOT expect to occur as a result of genomic damage?
Activation of the protein kinase ATR
Activation of the protein kinase Chk1
Inactivation of the protein phosphatase Cdc25
Binding of p53 to Mdm2
Binding of p53 to Mdm2
Which event contributes to helping the cells progress from G1 to S phase?
Activation of E2F gene expression
Destruction of CKIs that target S-Cdks
Phosphorylation of Rb by G1-Cdk, G1/S-Cdk, and S-Cdk
All of the above
All of the above
Which of these is an immediate early gene whose expression is triggered by Ras activation to promote cell cycle entry?
mTOR
Myc
S-Cyclin
Ubiquitin ligase
Myc
ATM and ATR kinases phosphorylate Ser-15 residue in p53 which________.
Inhibits p53
Enhances its interaction with Mdm2
Stabilizes p53
Inhibits p21
Stabilizes p53
G1/S Cdk also phosphorylates and inactivates APC/C towards end of G1 phase, which directly helps in accumulation of ………………
Rb
S-Cyclin
p53
ATR
S-Cyclin
Retinoblastoma is caused by excessive proliferation of some cells in retina that is induced by ………………
high Rb activity
high CKI activity
high E2F activity
high p53 activity
high E2F activity
The Chk1-mediated checkpoint response to DNA damage can arrest cells in G2/M phase by inhibiting which of these factors?
ATM
ATR
Cdc25
Rb
Cdc25
Which of these is the purpose of activating cell cycle checkpoint responses to DNA damage?
promote cell death if damage is excessive.
halt cell cycle to facilitate DNA repair.
halt cell cycle to suppress accumulation of mutations.
All of the above.
All of the above.
p53 expression is often lost in early stages of cancer development, and in the absence of p53, which of these factors serve to initiate key cell cycle checkpoint-response to DNA damage? (see lecture-8 ppt.)
p21
14-3-3 sigma
Chk1
Wnt
Chk1
A regulator critical for enhancing cell growth through stimulation of protein synthesis rates is ………..
mTORC1
TSC
Gator1
Chk1
mTORC1
