Raj Patel L1

Question 1

How do cancer cells utilise apoptosis?

Answer 1

Cancer cells avoid apoptosis

Question 2

Name two cancers where the lymphocytes evade apoptosis

Answer 2

CML - chronic mylenoid leukaemia; ALL - acute lymphoblastic lymphoma

Question 3

What are the four mechanisms of cell death?

Answer 3

1) Cell death by suicide/apoptosis; 2) Necrosis; 3) Cell death by injury; 4) Autophagy

Question 4

Name three characteristics of nectrotic cells?

Answer 4

1) The cell swells; 2) The cell contents leak out; 3) Inflammation of the surrounding tissues

Question 5

Name nine characteristics of apoptotic cells?

Answer 5

1) Cell shrinks; 2) Plasma membrane blebbing; 3) Chromatin condensation; 4) Nucleus shrinks + chromatin degradation; 5) Mitochondrial breakdown, release of apoptotic mediators; 6) Cell breaks into apoptotic bodies; 7) Phosphatidyl serine translocation to outer membrane; 8) PS binds phagocytic cells & engulfing; 9) Phagocytes release cytokines, anti-inflammatory

Question 6

Plasma membrane blebbing occurs by what mechanism?

Answer 6

Caspase-3 mediated activation via Rho to constituently activate ROCK1.

Question 7

Role of apoptosis in embryonic development?

Answer 7

Apoptopsis is used to define body features, for examples, gaps between fingers and toes. Mutations or error in apoptotic pathways leads to malformed areas where apoptosis should take place, e.g., webbed fingers & toes.

Question 8

Apoptosis is required in post-natal organisms to?

Answer 8

Get rid of cells which could be detrimental to the survival of the organism

Question 9

Signals that lead to apoptosis

Answer 9

1) Removal of positive signals such as survival signalling and growth factors; 2) Introduction of negative signals, i.e. death signals, accumulation of misfolded proteins.

Question 10

Assays are used in the lab to?

Answer 10

Identify apoptotic cells

Question 11

The M30 antibody stains for?

Answer 11

Cytokeratin-18, which is only present in apoptosis

Question 12

How can DNA fragmentation be detected?

Answer 12

DNA fragmentation occurs in apoptosis where the DNA is cleaved by nucleases into 200bp fragments. This can be detected by agarose gel electrophoresis, and also TUNEL assays where 3’OH’s are labelled with BrdUTP, which can be visualised on UV.

Question 13

What does the annexin binding assay show?

Answer 13

Annexin is a 35kDa protein, which binds phosphatidyl serine following binding calcium. Phosphatidyl serine is only on the outside of apoptotic cells. This can be detected by biotynilation

Question 14

The molecules regulating apoptosis were discovered in?

Answer 14

The nematode worm, C.elegans

Question 15

What did Sydney Bremner, 2002 show regarding apoptosis in nematode worms?

Answer 15

By tracking development, the same cells are shown to undergo apoptosis in all cases. First divisions occur in the uterus, after hatching there are four stages of apoptosis before adulthood and a final phase in adults. This lead to the identification of >20 cell death genes

Question 16

What are the four categories of cell death genes?

Answer 16

1) Decision to enter cell death; 2) excecution of apoptosis; 3) engulfment; 4) Degradation of DNA

Question 17

How was the function of Egl-1, and ced 3, 4 and 9 determined?

Answer 17

Loss and gain of function mutations. Egl-1 and ced 3&4 show survival with a loss of function mutation. Ced9 shows death with a loss of function. Egl-1 and ced 3&4 are pro-apoptotic, while ced9 is antiapoptotic

Question 18

Egl-1 is?

Answer 18

Pro-apoptotic BH3 only-domain protein

Question 19

Ced-9 is?

Answer 19

Anti-apoptotic protein with 4 Bcl-2 homology domains

Question 20

Ced-4 is?

Answer 20

Pro-apoptotic adaptor protein

Question 21

Ced-3 is?

Answer 21

Pro-apoptotic protease of the caspase family

Question 22

C.elegans apoptosis is regulated by?

Answer 22

A series of protein protein interactions.