After mitosis completes the formation of a pair of daughter nuclei, cytokinesis finishes the cell cycle by dividing the cell in two. Which is true of cytokinesis?
a. it occurs at the start of S-phase
b. it is activated by expression of c-cyclin (cytokinesis) and C-cyclin-dependent kinases (C-CDK)
c. tubulin rearrangements (assembly and dynesin mediated contraction) form the cleavage furrow
d. position of the contractile ring (comprised of actin and myosin proteins) is determined by signals emanating from the microtubules of the mitotic spindle (the inter-polar microtubules)
e. the two daughter cells potion themselves to enter s-phase
a patient with advanced stage ebola infection will be bleeding from their eyes, mouth, nose, and anus. This hemorrhaging is caused activating and exhausting the supply of all the seren proteases that are normally used to activate thrombin and fibirin during clot formation. By what mechanism are these proteases kept active in a healthy human
a. they are sequestered in microsomes
b. they are expressed as pro-proteins or zymogens
c. they are bound and transported by serum albumin
d. they are inhibited by alkaline pH
e. they are inactivated by glycosylation
which of the following is true
a. tumor initiators introduce mutations into the DNA of somatic cells
b. benign cancers invade surrounding tissues and colonize distant organs
c. benign tumors induce apoptosis in response to cell stress or DNA damage
d. metastatic cancers activate the intrinsic but not extrinsic apoptosis pathway
e. cancer cells acquire stable genetic phenotypes
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