Apoptosis

Question 1

unintentional cell death

Answer 1

necrosis

Question 2

requires ATP, changes in gene expression, and proteins synthesis

Answer 2

apoptosis

Question 3

Progression of Apoptosis: cell shrinkage and rounding then chromatin undergoes condensation forming patches against the nuclear envelope called

Answer 3

pyknosis

Question 4

Progression of Apoptosis: nuclear envelope becomes discontinuous and DNA is fragmented and this is called

Answer 4

karyorrhexis

Question 5

Progression of Apoptosis: nucleus breaks into discrete chromatin bodies due to degradation of DNA and the cell membrane shows irregular bud called

Answer 5

blebs

Question 6

Progression of Apoptosis: cell breaks apart into several vesicles called what before being phagocytised by neighboring cells

Answer 6

apoptotic bodies

Question 7

apoptosis role during development

Answer 7

tissue remodeling (digit formation), elimination of transitory organs and tissues, nervous system formation

Question 8

three main component of apoptotic pathway

Answer 8

regulators, adapters, effectors (caspases)

Question 9

inhibit apoptosis or initiate apoptotic pathway

Answer 9

regulators

Question 10

bind to procaspases and either facilitate proteolytic of procaspases to active caspases directly or by cause the aggregation of procaspase resulting in self activation

Answer 10

adapters

Question 11

serve to execute apoptosis by targeting various cellular components and enzymes

Answer 11

effectors (caspases)

Question 12

how are procaspases activated

Answer 12

they are activated by proteolytic cleaving hence forming active caspase (large and small subunit) and prodomain(cleaved off) then a bunch of active caspases can activate other procaspases

Question 13

stimuli that activate apoptosis

Answer 13

Genotoxic damage
Viral infection Microtubule disruption
ER damage
Hypoxia 
Hypoglycemia 
Reactive oxygen species 
Mitochondrial damage 
Death receptor activation
Growth factor withdrawal 
Anoikis (detachment from ECM)

Question 14

intrinsic pathway is responsible for eliminating cells in response to

Answer 14

genotoxic damage, mitochondrial damage, absence of growth factors, loss of substrate adhesion etc

Question 15

what is the intrinsic pathway of apoptosis

Answer 15

cell and DNA damage activate protein kinases that phosphorylate and activate p53 (TF)

p53 binds to DNA and causes transcription of BAX and cell cycle inhibitor p21

BAX inserts into mito membrane and causes release of cytochrome C from mito

cytochrome C binds to the adapter protein Apaf-1 causing aggregates and binds procaspase (apoptosome complex)

procaspases are cleaved to form active form –> caspases

Question 16

extrinsic pathway is responsible for elimination of

Answer 16

unwanted cells during development, termination of immune responses, and immunosurveillance

Question 17

extrinsic pathway uses what caspases for initiation of apoptosis

Answer 17

caspases 8 and 10

Question 18

extrinsic pathway is initiated by activation of

Answer 18

Tumor Necrosis Factor (TNF) receptor family of “cell death receptors” such as the Fas receptor

Question 19

extrinsic pathway: first step

Answer 19

killer lymphocytes express FAS ligands on their cell surface

Question 20

extrinsic pathway: how do killer lymphocytes bind to target cells

Answer 20

through the FAS Death receptors

Question 21

extrinsic pathway: once the FAS ligand and its receptors are bound…what do they do next

Answer 21

they recruit adaptor molecules through binding between the receptor death domain and the adapter cell domain —>procaspases aggregate by binding to the “death effector domain” of the adaptor hence forming DISC (Death-inducing signaling complex)

Question 22

extrinsic pathway: what happens after procaspases have aggregated at the death effector domain

Answer 22

they are cleaved to form active caspase 8 which then activate other procaspases —> lead to apoptosis

Question 23

how are extrinsic and intrinsic pathways coupled

Answer 23

Death Receptors activate Bid which subsequently activates Bak and Bax

Question 24

what pathway is activated in response to viral infected cells

Answer 24

perforin/granzyme pathway

Question 25

perforin/granzyme pathway: what secretes perforin and granzyme

Answer 25

cytotoxic T cells

Question 26

perforin/granzyme pathway: what does perforin do

Answer 26

forms pore in target cells

Question 27

perforin/granzyme pathway: what does granzyme do

Answer 27

they enter the cells through the perforin and activate caspase 10 into resulting in inactivation of apoptotic inhibitors and activate caspase 3 to execute apoptosis

Question 28

target of caspases

Answer 28

apoptosis regulators, cell adhesion molecules, cytoskeletal proteins, and nuclear structural proteins

Question 29

what can inhibit apoptosis

Answer 29

binding of extracellular survival factors to cell surface receptors —> activation and production of apoptotic inhibitors such as Bcl-2 and the inactivation of proapoptotic proteins such as Bad

Question 30

cells that require constant signaling to prevent apoptosis

Answer 30

nerve cells during development

Question 31

p53 can induce apoptosis by increasing expression of

Answer 31

pro-apoptotic Bcl2 family members, FAS receptors (CD95), IGFBP-3

Question 32

dna fragmentation in apoptotic cells facilitated by

Answer 32

caspase activated Dnase enzyme that cleaves at internucleosomal sites

Question 33

cleavage typically occurs at ____ intervals resulting in a ladder effect when apoptotic DNA is visualized by gel electrophoresis.

Answer 33

180 bp

Question 34

how are DNA cell fragmentation detected in cells in situ

Answer 34

using DNA end labeling techniques such as

TUNEL

Question 35

Changes in the plasma membrane of an apoptotic cell results in the exposure of

Answer 35

phosphatidylserine

Question 36

what type of assays can be used to detect active caspase

Answer 36

caspase assay

Question 37

labeled antibodies for ______ can label apoptotic cells

Answer 37

annexin 5

Question 38

cancer cells express high levels of proteins and low levels of what proteins

Answer 38

high level of apoptotic inhibitors Bcl2

low levels of apoptotic cells p53

Question 39

common neurodegenerative disorder

Answer 39

Alzheimers

Question 40

Alzheimer’s is characterized by the presence of

Answer 40

senile plaques, neurofibrillary tangles, and massive loss of neurons

Question 41

genes implicated in alzheimers

Answer 41

amyloid precursor protein (APP)
apolipoprotein E
presenilins 1 (PS1) and 2 (PS2)

Question 42

in alzheimers brain, there is increased levels of

Answer 42

proapoptotic Bak and Bad protein

Question 43

amyloid precursor protein (APP), presenilins 1 and 2 (PS1 and PS2) are cleaved by

Answer 43

caspase 3 (its activity increased)

Question 44

HIV infection leads to inactivation of what proteins

Answer 44

anti apoptotic protein Bcl2 and activation of procaspases

Question 45

HIV infection promotes what pathway in CD4+ cells

Answer 45

extrinsic FAS mediated apoptosis

Question 46

HIV proteins such as tat, nef and vpr may induce apoptosis by interacting with

Answer 46

p53