C $15.$ 'programmed cell death' is:

a$.$ necrosis

b$.$ anastasis

c$.$ apoptosis

d$.$ none of the above

$q,16.$ proteins hold the sister chromatids together

a$.$ condensins

$($b$.)$ cohesins

c$.$ MPF

d$.$ cyclins

$a$

$17.$ Destruction of 'securin' is:

a$.$ anaphase checkpoint

b$.$ S phase checkpoint

c$.$ G$1$ checkpoint

d$.$ G$2$ checkpoint

$q,18.$ Which of the following DOES NOT HAPPEN upon DNA damage?

a$.$ The ATM$/$ATR genes are induced

b$.$ The ATM gene product leads to p$53$ stabilization

$($c$.)$ p$53$ degrades quickly

d$.$ p$53$ induces p$21$ which blocks cell cycle progression

$q,19.$ p$53$ is:

a$.$ an oncogene

$($b$.)$ a tumor suppressor gene

C$.$ a CDK

d$.$ all of the above

a

$20.$ A proto$-$oncogene is:

$($a$.)$ a gene responsible for cell growth

b$.$ a gene responsible for cell cycle arrest

c$.$ deactivated by a gain of function mutation

d$.$ all of the above