Apoptosis

Question 1

what are the 2 ways in which cells die

Answer 1

necrosis and apoptosis

Question 2

features of necrosis

Answer 2

its a passive process, involves groups of cells, cell swells and bursts, DNA breaks into random fragments, cells contents are released, inflammation

Question 3

features of apoptosis

Answer 3

its an active process, involves single cells, cell shrinks and forms apoptotic bodies, DNA breaks into nucleosome sized fragments no cell content release, no inflammation

Question 4

biological roles of apoptosis are

Answer 4

tissue sculpturing and homeostasis, immune system function, removal of damaged cells

Question 5

apoptotic cells display an altered

Answer 5

mitochondrial permeability, the m Proteins are released into the cytoplasm

Question 6

apoptotic cells display - in reference to their plasma membranes

Answer 6

alterations in symmetry, phosphatidyl serine is exposed on the extracellular side which functions as a eat me signal

Question 7

what proteins are required for apoptosis

Answer 7

CED3, CED4

CED9 inhibits apoptosis

Question 8

proteins involving apoptosis can be divided into 3 classes

Answer 8

~regulators: promote or suppress apoptosis
~adapters: interact with regulators/effectors in response to specific signals
~effectors: enzymes that execute apoptosis

Question 9

caspases

Answer 9

are the key effectors of apoptosis, not present in prokaryotes, contain a Cys residue in active sites, they cut the substrate in specific sequences after an Asp residue

Question 10

how do you activate caspases?

Answer 10

they are synthesized as inactive enzymes, their activation requires proteolytic and cleavage oligomerization. Note 2 procaspases molecules form on active caspase molecule

Question 11

caspases 2,8,9,10 work as

Answer 11

initiator caspases

Question 12

caspases 3,6,7, work as

Answer 12

effector caspases

Question 13

what are the substrates for caspases

Answer 13

proteins needed for cell survival

Question 14

degradation of CAD nuclease triggers

Answer 14

chromatin fragmentation

Question 15

the intrinsic pathway for caspase initiation, That depends on mitochondria, steps are

Answer 15

presence of an apoptotic stimulus, pro-apoptotic Bax/Bak pore formation, release of cytochrome C and then the formation of an apoptosome (which is cytochrome C and Apaf1), activation of initiator caspase 9

Question 16

Bcl 2 proteins

Answer 16

regulate the intrinsic pathway of apoptosis

Question 17

when is the intrinsic pathway activated

Answer 17

in the absence of trophic factors, and when DNA is damaged which activates p53

Question 18

the extrinsic pathway depends on

Answer 18

surface death receptors and the formation of a DISC complex

Question 19

list the steps for the extrinsic pathway

Answer 19

death signal (Fas ligand or TNF), activation of dead receptor, formation of DISC complex (including death inducing signaling complex), activation of initiator caspases 8,10

Question 20

the extrinsic pathway can be used for

Answer 20

eliminating virus infected cells, it is important for an immune response

Question 21

apoptosis is regulated by

Answer 21

pro-apoptotic and anto-apoptotic factors

Question 22

the negative regulators of apoptosis are

Answer 22

BCL-2 IAP FLIP

Question 23

the positive regulators of apoptosis are

Answer 23

BAD BAX BID AIF SMAC DIABLO