Cell Death

Question 1

Definition of necrosis
Cause of necrosis

Answer 1

Death of tissues following bioenergetic failure and loss of plasma integrity.
Ischaemia, trauma, metabolic reactions.

Question 2

Types of necrosis and appearance

Answer 2

-Coagulative- firm pale area, present in most tissues, especially those rich in fat

-Colliquative- dead area liquefies- brain

-Caseous- flaky-cheese-like consistency and yellow in colour mass. Caused by tuberculosis.

-Gangrene- putrefaction due to vascular blockage or infection. Appears black
-Fibrinoid- causd by malignant hypertension and present in arterioles
-Fat- caused by trauma or pancreatitis. Cause a mass or multiple white spots

Question 3

Apoptosis uses

Answer 3

-Embriology
-Immune defence- T and NK cells trigger apoptosis in diseased cells
-Inflammation- resolution and death of neurtrophils
-Tumour prevention- triggering apoptosis in cancer cells.
-Autoimmune disease
-HIV/AIDS- they trigger apoptosis of T cells
-Response to growth signals

Question 4

Characteristics of extrinsic apoptosis

Answer 4

External trigger (example cytokines) binds to receptor and triggers activation of caspase enzyme

Question 5

What’s caspase enzyme?

Answer 5

-Enzyme involved in fragmenting the cell during apoptosis.
-Can be activated from procaspase thanks to extrinsic and intrinsic pathways.

Question 6

Characteristics of intrinsic apoptosis

Answer 6

Triggered by damage of DNA, mitochondria and cell damage.
- Cytochrome c leaks out of the mitochondria and binds to Apaf-1 to form an apoptosome.
- Apoptosome activates caspase from procaspase.
-

Question 7

Where does the name caspase derive from

Answer 7

C for the cysteine present in the active site
-asp- because they cleave after aspartate
-ase because their protease enzymes

Question 8

Which are the survival factors that override apoptosis?

Answer 8

-Increased production of Bcl2
-Inactivation of pro-apoptotic BH3-only Bcl2 protein
-Inactivation of anti-IAPs

Question 9

What components can drugs target to treat lymphoma and alzheimer type dementia

Answer 9

• Anti- Bcl2 can targeT Bcl2 in lymphoma.
  -Caspase 3 in Alzheimer Type Dementia can be targeted with drugs.
  -IAP targeted in cancer with anti-IAPs for example

Question 10

What is pyroptosis?

Answer 10

Microbial trigger.
Bacteria enters macrophage and trigger activation of caspase 1.
Causing nuclear fragmentation and triggering inflammation.

Question 11

What is anoikis?

Answer 11

Death of cell after losing contact with basement membrane, extracellular matric or other cells.
Cancer cell lack this, allowing them to metastasise