Sp?rsm?l til kollokviene den 15. ¡­

Sp?rsm?l til kollokviene den 15. september

1. Explain how complex oligosaccaride-chains (in glycoproteins) are formed

2. What is the purpose of glycosylation

3. What are the functions of calnexin and calreticulin

4. What is the fate of misfolded proteins in the ER?

5. There is one strict requirement for the exit of a protein from the ER: it must be correctly folded. True/False? Explain your answer.

6 The C-terminal 40 amino acids of three ER-resident proteins ? calnexin, calreticulin and HMGCoA reductase ? are shown. Decide for each protein whether it is likely to be transmembrane or soluble. Explain your answer. Calnexin: KDKGDEEEEGEEKLEEKQKSDAEEDGGTVSQEEEDRKPKAEEDEILNRSPRNRKPRRE Calreticulin: KQDEEQRLKEEEEDKKRKEEEEAEDKEDDEDKDEDEEDEEDKEEDEEEDVPGQAKDEL HMG Reductase: PGENARQLARIVCGTVNAGELSLMAALAAGHLVKSHMIHNRSKINLQDLQGACTKKTA

7. If you remove the ER retrieval signal from protein difulfide isomerase (PDI) which is normally a soluble resident of the ER lumen, where would you expect the modified PDI to be located?

8. Difficult question: Design experiments to find out if proteins are transported through the Golgi according to the vesicular transport model or the cisternal maturation model (or both)!

9. What are the functions of Sar1, ARF, Rab-proteins and dynamin? What do these proteins have in common?

10. Present a model for vesicle traffick mediated by Rab and SNAREs. Do not forget NSF! Can you design a very simple experiment to test is vSNAREs and tSNAREs can mediate fusion between vesicles.

11. How does the HIV-virus enter a T-cell?

EKSAMEN:

Eksamen: F?rste deleksamen holdes 26. september (fredag) kl 9.00 til 10.00 p? Vilhelm Bjerknes Hus, Lesesalen

Hilsen Trond