Cell Death

Question 1

What is apoptosis?

Answer 1

Programmed cell death
-controlled, no inflammation!

Question 2

What are the 6 hallmarks of apoptosis?

Answer 2

1: cell SHRINKAGE and ROUNDING bc of breakdown of the cytoskeleton by caspases
2: the cytoplasm is dense and organelles are TIGHTLY PACKed
3: CHROMATIN is CONDENSED and packed against the NUCLEAR ENVELOPE
4: the NUCLEAR envelope is broken down and DNA is fragmented
5: the cell MEMBRANE shows irregular buds known as BLEBS
6: the cell breaks apart into APOPTOTIC BODIES which are then phagocytosed

Question 3

Does apoptosis require energy?

Answer 3

Yes! It requires the last of the cells energy

Question 4

What are Annexins?

Answer 4

-calcium dependent phospholipid binding proteins
-bind to PS and identify apoptotic cells

Question 5

What is Necrosis?

Answer 5

A cell death as a result of trauma, it’s messy, the PM breaks, contents leak out, and adjacent tissues become inflamed

Question 6

Does necrosis require energy?

Answer 6

No it doesn’t! Its passive the cell just bursts open, causing inflammation!

Question 7

Who does the dirty work of the apoptotic pathway?

Answer 7

Caspases!

Question 8

What is the chemical makeup of Caspases?

Answer 8

Cysteine in the active site plus ASPartic acid and it’s an enzyme!

Question 9

What is the extrinsic pathway?

Answer 9

1: Fas Ligand (immune cell) activates Fas receptor on the PM,
2: Death Domains are activated and recruit FADD
3: FADD makes Procaspase 8 become active Caspase 8
4: Caspase 8 then activates “executioner Caspases” 3 and 7

Question 10

What is DISC?

Answer 10

The Death Inducing Signaling Complex
-a part of the extrinsic pathway
-made up of Fas, Death Domains, FADD, and inactive procaspase 8

Question 11

What triggers the intrinsic pathway of apoptosis?

Answer 11

the release of Cytochrome C from the mitochondria

Question 12

What are the anti-apoptotic signals trying to defend against apoptosis?

Answer 12

Bcl-2, BCL-XL, and IAPs
(They block cytochrome C from being released)

Question 13

What are Pro-Apoptotic signals?

Answer 13

-BAX, BID, BAD, BIM, Puma, Noxa, SMAC/DIABLO
-they help cytochrome C get released from the mitochondria to try to initiate apoptosis!

Question 14

What is the pathway of the intrinsic pathway of apoptosis?

Answer 14

1: BID/BAD/etc cause cytochrome C to be released from the mitochondria
2: Cyt C. bind with APAF1 and procaspase 9 to make an APOPTOSOME
3: Caspase 9 is activated and calls in excutioner caspases 3,6, and 7 to kill stuff

Question 15

What makes up an APOPTOSOME?

Answer 15

APAF1, Cytochrome C, Procaspase 9

Question 16

How are the extrinsic and intrinsic pathways of apoptosis connected?

Answer 16

They activate each other!
-the extrinsic pathway will release BAX/BAK, and the intrinsic pathway will release caspase 9 which will activate caspase 3!
-ergo if one gets activated they both get activated!