1.8 Cell Death

Question 1

What is apoptosis?

Answer 1

programmed cell death used to eliminate unwanted cells

Question 2

The lack of apoptosis can lead to [ ] and [ ].

Answer 2

1. uncontrolled cell division
2. cancer

Question 3

What are the four components to cell death?

Answer 3

1. cell condenses
2. cytoskeleton disassembles
3. nuclear envelope breaks down
4. chromatin fragments

Question 4

Cell surface forms protrusions called [ ].

Answer 4

blebs

Question 5

Fragmentation typically occurs to allow [ ] to better [ ] the cell.

Answer 5

1. macrophages
2. engulf

Question 6

Why is it important for an apoptotic cell to be engulfed by macrophage?

Answer 6

1. allow death of cell to be neat. Cellular contents are easly cleared away
2. prevents damaging inflammatory responses

Question 7

What is necrosis?

Answer 7

Non-apoptotic way for damaged cells to die

Question 8

A common and passive form of necrosis is [ ] in response to tissue trauma

Answer 8

cell lysis

Question 9

The release of celular contents into surround environment causes [ ].

Answer 9

inflammatory response

Question 10

What are the four functions of apoptosis?

Answer 10

1. allows for shaping of appendages
2. kills cells of structures that are no longer needed
3. kills abnormal or non-functional cells
4. balances cell division in tissues that are maintaining relatively constant mass

Question 11

What is the function of caspase?

Answer 11

intracellular protease that are apoptosis by cleaving specific target proteins

Question 12

What is the composition of caspase?

Answer 12

have a cysteine (c) residue in their active site that is used to cleave their targets at specific aspartic (asp) residues. C + Asp + enzyme = Caspase

Question 13

What are the two major classes of apoptotic caspases?

Answer 13

1. initiator caspases
2. excutioner caspases

Question 14

What is the function of initiator caspases?

Answer 14

begins apoptosis. In mammals, these are caspase-8 and caspase-9

Question 15

Initiator caspses exist in cytosol as [ ], soluble monomers ([ ]). These contain a [ ].

Answer 15

1. inactive
2. procaspase
3. prodomain

Question 16

What is the function of executioner caspases?

Answer 16

coordinate apoptosis. In mammals, these are caspase-3, caspase-6, and caspase-7

Question 17

What is the caspase cascade?

Answer 17

each initiator can amplify the apoptotic signal by activating multiple executioners

Question 18

Caspase signaling is [ ] and [ ].

Answer 18

self-amplifying and irreversible

Question 19

An example of an executioner caspase target are the [ ], which make up the nuclear cytoskeleton (intermediate filaments).

Answer 19

nuclear lamins

Question 20

What are the two main pathways of initiator activation?

Answer 20

1. intrinsic pathway (mitchondrial pathway)
2. extrinsic pathway

Question 21

Extrinsic pathway is activated by extracellular apoptotic signals binding to [ ].

Answer 21

cell-surface death receptors

Question 22

What do death receptors contain?

Answer 22

1. extracellular ligand-binding domain
2. transmembrane domain
3. intracellular death domain

Question 23

What are the receptors of apoptosis?

Answer 23

homodimers belonging to tumor necrosis family (TNF) receptor family. Includes the Fas ligand.

Question 24

TNF receptors bind ligands from the [ ].

Answer 24

TNF family of signal proteins

Question 25

Fas signaling plays a role in regulating number of [ ].

Answer 25

T and B lymphocytes

Question 26

The intrinsic pathway depends upon the [ ] into the cytosol.

Answer 26

release of mitochondrial proteins

Question 27

Signal molecules normall reside in [ ] (intrinsic pathway).

Answer 27

intermembrane space

Question 28

Most important of these signals is [ ] of the electron transport chain (intrinsic pathway).

Answer 28

cytochromc C

Question 29

What is the function of Bcl2 family of proteins?

Answer 29

regulate the intrinsic pathway by controlling permeabilization of the outer mitochondrial membrane

Question 30

What are the three functional and structural classes of Bcl2 proteins?

Answer 30

1. anti-apoptotic Bcl2 2. pro-apoptotic Bcl2 3. BH3-only proteins

Question 31

What is the function of anti-apoptotic Bcl2?

Answer 31

inhibits apoptosis by preventing mitochondrial outer membrane permeabilization (MOMP)

Question 32

What is the function of pro-apoptotic Bcl2?

Answer 32

creates openings in outer membrane to induce MOMP and promotes apoptosis

Question 33

What is the function of BH3-only proteins?

Answer 33

pro-apoptotic. Regulates the two classes above

Question 34

What is the function of inhibitors of apoptosis proteins (IAPs)?

Answer 34

protect against inappropriate apoptosis by inhibiting caspase enzymes (caspase-9 and caspase-3, caspase-7)

Question 35

Mammals have one type of IAPs ([ ]) that is encoded on the X chromosomes.

Answer 35

XIAP

Question 36

Survival factors are [ ].

Answer 36

extracellular signals that inhibit apoptosis

Question 37

Survival factors bind to [ ] that inhibit [ ].

Answer 37

1. cell surface receptors 2. the apoptotic pathway

Question 38

What are the three functions of survival factors?

Answer 38

1. regulate the expression or activity of Bcl2 family of proteins 2. promote synthesis of anti-apoptotic Bcl2 proteins 3. inhibit pro-apoptotic BH3-only proteins