Lecture 04

Question 1

This gene/protein is the precursor for cell cycle arrest, senescence, or apoptosis.

Answer 1

p53

Question 2

Similarity between quiescence and senescence

Answer 2

Both means cells do not proliferate.

Question 3

MAIN difference of quiescence and senescence

Answer 3

Quiescence - due to lack of nutrition; reversible
Senescence - due to agingor serious DNA damages; mostly irreversible

Question 4

Senescence or Quiescence.
Results to hypertrophic cell

Answer 4

Senescence

Question 5

Senescence or Quiescence.
Growth without proliferation

Answer 5

Senescence

Senescence leads to HYPERTROPHY.

Question 6

Senescence or Quiescence.
No proliferation and growth

Answer 6

Quiescence

Question 7

Senescence or Quiescence.
Due to shortage of growth factors

Answer 7

Quiescence

Question 8

These are markers of senescent cells

Answer 8

Lipofuscin

Question 9

The marker of senescent cells is usually stored in which organelle

Answer 9

Lysosome

Question 10

What are the FOUR hallmarks of senescence

Answer 10

1. Cell Cycle Arrest
2. Macromolecular Damage
3. Deregulated Metabolism
4. Secretory Phenotype

Question 11

T or F. Senescent cells may lead to apoptosis.

Answer 11

True. With senolytics

Question 12

T or F. Necrotic cells can lead to senescence

Answer 12

False

Question 13

What is efferocytosis?

Answer 13

Phagocytosis of apoptosized* cells by immune cells

• not a real word

Question 14

Necrosis or Apoptosis.
Cell lysis occurs.

Answer 14

N

Question 15

Necrosis or Apoptosis.
One cell affected

Answer 15

A

Recall why.

Question 16

Necrosis or Apoptosis.
Cell shrinks

Answer 16

A

Question 17

Necrosis or Apoptosis.
Many cells are affected

Answer 17

N

Recall why.

Question 18

Necrosis or Apoptosis.
Formation of blebbing

Answer 18

A

Question 19

Necrosis or Apoptosis.
Cell contents are ingested by neighboring cells

Answer 19

A

In necrosis, cell contents are ingested by macrophage (but this is not a

Question 20

T or F. The assembled adaptor-protein complex activates the initiator caspase monomers by assembling the monomers into dimers.

Answer 20

True

Question 21

T or F. The assembled adaptor-protein complex assembles the initiator caspase monomers into a dimer and further cleaves the monomers to form the mature active initiator caspase.

Answer 21

False.

Question 22

Which cleaves the monomers to become mature?

Answer 22

The monomer partners themselves (CROSS-CLEAVAGING)

Question 23

T or F. The removal of the webs between the digits of mammals is caused by apoptosis.

Answer 23

T

Question 24

T or F. The removal of the tail of frogs is caused by necrosis.

Answer 24

F. The removal of the tail of frogs is also caused by apoptosis.

Question 25

T or F. Apoptotic cells can then undergo necrosis.

Answer 25

False

Question 26

In both caspase proteins (initiator and executor), this subunit is cleaved to activate them.

Answer 26

Prodomain

Question 27

Which protein activates the executioner caspase dimer. Be specific.

Answer 27

Mature active initiator caspase

Question 28

The following are true for both initiator and executor caspase, EXCEPT: a. They have prodomain, which is cleaved to activate the caspase proteins. b. Both are activated by caspase protein c. Is pro-apoptosis d. Aids for cleavage of other proteins

Answer 28

B. Initiator caspase is activated by assembled adaptor-protein complex, NOT a caspase

Question 29

Other name for executioner caspase

Answer 29

Caspase-3, 8, 9

Question 30

Executor caspase activates _______ by cleaving _______

Answer 30

CAD; iCAD

Question 31

T or F. The executor caspase acts as an inhibitor protein of CAD.

Answer 31

False. iCAD acts as an inhibitor protein of CAD. Executor caspase ACTIVATES CAD.

Question 32

Function of active CAD

Answer 32

Cleaves DNA between nucleosome

Question 33

T or F. Both initiator and executor caspase normally exist as an inactive monomer.

Answer 33

False. Only initiator caspase normally exists as an inactive monomer. Executioner caspase normally exists as an inactive DIMER.

Question 34

Differentiate extrinsic and intrinsic apoptotic pathway.

Answer 34

Extrinsic - signal coming from outside the cell. Intrinsic - signaled from mitochondria

Question 35

Intrinsic pathway is also called the ___________.

Answer 35

Mitochondrial pathway

Question 36

Explain extrinsic apoptotic pathway briefly

Answer 36

Lymphocyte's Fas ligand activates Fas death receptor. Creates/oligomerizes DISC. DISC enables formation of executioner caspase. Executioner caspase targets apoptotic cells.

Question 37

Explain intrinsic apoptotic pathway briefly.

Answer 37

Release of cytochrome c to cytosol. Cyt c binds to inactive Apaf 1 to become active Apaf1. Apaf1 oligomerizes into an apoptosome. Executioner caspase is made.

Question 38

Pro-apoptotic Bcl2 family effectors

Answer 38

Bak, Bax

Question 39

Anti-apoptotic Bcl2 family proteins

Answer 39

Bcl2, BclxL, Mcl1

Question 40

Pro-apoptotic (anti-anti-apoptotic) BH3-only proteins

Answer 40

Bad, Bim, Bid, Puma, Noxa