Chapter 18: Apoptosis

Question 1

What is the normal relative concentration of the p53 protein in cells?

Answer 1

Low

Question 2

This is an apoptosis gene regulatory protein that, when mutated, is located in 50% of all cancers

Answer 2

P53

Question 3

This is a negative regulator of p53 and tends to inhibit transcriptional ability

Answer 3

MDM2

Question 4

What are 3 things MDM2 does to p53?

Answer 4

1. Inhibits transcriptional ability
2. Favors p53 nuclear export
3. Stimulates degredation

Question 5

P53 mutation can do what 2 things to MDM2?

Answer 5

1. Reduce MDM2 production
2. Phosphorylate MDM2

Question 6

What happens in a cell with a mutated p53 protein/gene?

Answer 6

Makes p53 incapable of responding to DNA damage properly by arresting in the cell in G1; can lead to cancer/tumor growth when it ignores apoptosis signals

Question 7

When p53 behaves abnormally, where does it bind?

Answer 7

nowhere lol…she do be getting digested

Question 8

P21 RNA translates to what?

Answer 8

Cyclin dependent kinase (cdk) inhibitor protein

Question 9

What is the end protein that is inhibited with a mutated p53 gene/protein?

Answer 9

lol nothing

Question 10

What are 3 reasons why cell prefer apoptosis over other types of cell death?

Answer 10

1. Controlled and organized
2. Timely
3. Not as dmging at necrotic lysis

Question 11

When is apoptosis induced in cells? (4)

Answer 11

1. Mutations
2. Dysfunction
3. Immune system
4. Development

Question 12

Apoptosis in the immune system focuses on the destruction of what?

Answer 12

Non-functional immune cells/receptors to save enrgy

Question 13

What are 5 basic steps of apoptosis?

Answer 13

1. Cell shrinkage
2. Cytoskeleton collapses
3. Nuclear envelope dissassembly
4. Nuclear DNA fragmentation
5. Phagocytosis (via surface cell signals)

Question 14

What 2 things is apoptosis dependent on?

Answer 14

1. Energy capability
2. mRNA machinery (to make protein)

Question 15

A family of endoproteases that provide critical links in cell regulatory processes for apoptosis?

Answer 15

Caspases (cysteine-aspartic acid proteases)

Question 16

This intercellilar character of apoptosis blocks cytochrome c release from mitochondria (blocks a route of apoptosis)

Answer 16

Bcl-2 protein

Question 17

What does IAP stand for?

Answer 17

Inhibitor of apoptosis protein

Question 18

This is a key molecule in the mitochondrial pathway of apoptosis; forms wheel of death (apoptosome)

Answer 18

APAF-1

Question 19

This is released from mitochondria in response to death signals

Answer 19

Cytochrome c

Question 20

What actions produce an active caspase ?

Answer 20

Dimerization, activation, and cleavage of inactive monomers

Question 21

What induces the dimerization of caspases?

Answer 21

Adaptor proteins

Question 22

The cleavage of an active caspase prodcues what? This product cleaves many substrates to induce apoptosis

Answer 22

Executioner caspases (3, 6, 7)

Question 23

What are the two sources of death signals?

Answer 23

1. Extrinsic
2. Intrinsic

Question 24

The activation of a cell’s surface death receptors is an example of what source of apoptosis signals?

Answer 24

Extrinsic

Question 25

The activation of death receptors creates what protein complex?

Answer 25

DISC (death-inducing signal complex)

Question 26

What does the DISC protein do?

Answer 26

Further cleavage and production of executioner caspases

Question 27

This is a source of apoptosis signal that is received from within the cell itself

Answer 27

Intrinsic

Question 28

What are 3 triggers of intrinsic apoptosis?

Answer 28

1. Heat 2. Excess radiation 3. Viral infection

Question 29

What are the 4 steps of basic intrinsic apoptosis?

Answer 29

1. cytochrome c binds to APF-1 2. Apoptosome assembly of APAF-1 aggregations (~7) 3. Capsase 9 cleaving + dimerization 4. Caspase executioner cascade occurs

Question 30

What 3 things can override/out compete apoptosis signals?

Answer 30

1. Inreased Bcl2 2. BH3 inactivation 3. Anti-IAP inactivation