Cell cycle/apoptosis

Question 1

What kind of biochemical mechanisms regulate progression of cell cycle before DNA replication?

Answer 1

Definition and events of the G0, G1 and S phase, characterization of the R point.
* Describe the changes in the activity of the cyclin genes and cyclin dependent kinases
in the G1 phase!
* Characteristics of the mitogenic cascade. How does it lead to the crossing of the
restriction point?
* Describe in details the events and processes shown on slide 29!
* How can the cell cycle be stopped at the G1/S restriction point?

Question 2

What kind of biochemical mechanisms regulate progression of cell cycle after DNA replication?

Answer 2

Definition and events of the S, G2 and M phase
* Activation mechanisms of the M-phase kinase
* Activation of the APC complex, and its role in the cell cycle
* Proteolytic processes regulating the cell cycle
* Role and regulation of the G2/M checkpoint
* Role and regulation of the M phase checkpoint

Question 3

The major steps in the biochemical pathway leading to apoptosis from death receptors to DNA cleavage without activation of procaspase 9.

Answer 3

• Signal transduction pathway of the FASL-receptor (include the relevant information from the Signal lecture as well!)
• Activation of procaspase-3 and molecular consequences
• Activation of procaspase-12
• p53-dependent processes, without procaspase 9 activation

Question 4

The major steps in the biochemical pathway leading to apoptosis from death receptors to DNA cleavage with activation of procasepase 9

Answer 4

Signal transduction pathway of the FASL-receptor (include the relevant information from the Signal lecture as well!)
* Possible mechanisms of Bid protein cleavage
* Mechanism of cytochrome c exit from the mitochondrium
* Formation of the apoptosome
* p53-dependent processes, leading to procaspase 9 activation

Question 5

Characteristic differences between oncogenes and tumor suppressor genes in regulation of cell cycle.

Answer 5

General characteristics of oncogenes and tumor suppressor genes: slide 134.

Possible molecular mechanisms leading to the higher activity of oncogenes (at least 3 mechanisms). Write more than just keywords - explain briefly why the given mechanism results in higher oncogenic protein activity in the cell.

Possible molecular mechanisms leading to the suppressed activity of tumor suppressor genes: (at least 3 mechanisms, e.g. mutation, gene deletion, chromosomal rearrangement, promoter hypermethylation, and combinations of these). Write more than just keywords - explain briefly why the given mechanism results in lack of tumor suppressor protein activity in the cell.