apoptosis

Question 1

apoptosis vs necrosis

Answer 1

Apoptosis is programmed cell death that is organized and uses ATP. Necrosis is triggered by injury or infection and does not use ATP. Necrosis also produces swelling and disruption of cells (inflammatory cell death)

Question 2

role of apoptosis?

Answer 2

embryonic development
homeostasis
cell differentiation
removing damaged cells
immune surveillance
growth

Question 3

how is mitochondria different in apoptosis vs necrosis?

Answer 3

In apoptosis mitochondria releases its contents like cytochrome c that activates programmed cell death.
In necrosis, the mitochondria swells.

Question 4

what are proapoptotic proteins?

Answer 4

BAK, BAX, BAD, Bik, Bid, Bim,

Question 5

what are antiapoptotic proteins?

Answer 5

BCL-2 and BCL-X

Question 6

describe activation of apoptosis from extrinsic pathway

Answer 6

1. FAS ligand from killer lymphocyte binds to FAS protein receptor on the target cell
2. FADD recruits procaspase 8 and procaspase 10
3. aggregation and cleavage of procaspase-8 molecules activates caspase 8
4. activated caspase-8 initatiates caspade cascade which results in apoptosis

Question 7

describe activation of apoptosis from intrinsic pathway

Answer 7

1. cytochrome c in intermembrance space of mitochondria is released into the cytoplasm where it binds to APAF-1
2. Aggregation of APAF-1 then binds to procaspase-9.
3. activated procaspase-9 results in caspase cascade

Question 8

what triggers mitochonrial-dependent apoptosis?

Answer 8

oxidants
calcium ions
proapoptotic proteins (BAX, BAK, tBid) to the mitochondrial outer membrane

Question 9

what can block release of cytochrome c from the mitochondrial intermembrane space?

Answer 9

Bcl2

Question 10

what makes up the apoptosome?

Answer 10

1. Apaf-1
2. dATP
3. cytochrome c
4. caspase 9

Question 11

what does activation of procaspase 9 lead to ?

Answer 11

cleavage of procaspase 3 resulting in apoptosis

Question 12

what are death substrates?

Answer 12

ICAD
lamin
vimentin
actin

Question 13

what is necroptosis?

Answer 13

programmed form of necrosis
viral defense mechanism (cellular suicide)
in presence of viral caspase inhibitors to restrict virus replication.

Question 14

what is necroptosis used for?

Answer 14

defense against pathogens by the immune system

Question 15

what is a mitogen?

Answer 15

peptide/protein that stimulates cell division (mitosis)

Question 16

what does the binding of mitogen lead to?

Answer 16

activation of Ras and MAP kinase cascade

Question 17

what is myc?

Answer 17

family of regulator genes and proto-oncogenes that code for transcription factors.

Question 18

what does p53 induce?

Answer 18

apoptosis

Question 19

what does excessive myc lead to?

Answer 19

activation of p19ARF which inactivates Mdm2 which increases p53 which causes apoptosis

Question 20

what does protein kinase B (PKB) aka AKT do?

Answer 20

It supresses apoptosis (when a survival factor binds to cell receptor). AKT phosphorylates and inactivates the Bcl-2 family member Bad which causes apoptosis. phosphorylated Bad makes it dissociate from Bcl-2 which suppresses apoptosis.

Question 21

what is ferroptosis?

Answer 21

programmed cell death dependent of iron and accumulates lipid peroxides.

Question 22

what is pyroptosis?

Answer 22

a cytotoxic process in macrophages after proteolysis of gasdermin D.

Question 23

what is anastasis?

Answer 23

a reversal of apoptosis even after caspase activation

Question 24

what is efferocytosis?

Answer 24

apoptotic cells are removed by phagocytic cells

Question 25

what is autophagy?

Answer 25

self eating. the use of cell material to provide energy under nutritional deprivation

Question 26

what is the function of autophagy?

Answer 26

to remove damaged organelles and proteins

Question 27

what can lead to necrosis?

Answer 27

loss of ATP or NAD

Question 28

how does mitochondria induce apoptosis?

Answer 28

by activating pro-caspase9