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1 Describe 3 specific roles for Ubiquitin

2 Ca+2 is the lowest concentration cation in cell cytoplasm. This is so it canbe used to perform important intracellular signaling. Describe in detail 4signaling events that involve Ca2+ ions.

3 The pH of the cytosol and nucleus is ~ 7.2 (neutral). The pH of theorganelles in the secretory and biosynthetic pathway becomes progressivelymore acidic. The lysosome lumen has a pH ~5. The lumen of all secretory/biosynthetic organelles becomes acidified by the activity of what protein?What kind of a transporter is this?

4 Insulin and glucagon are hormones released by regulated exocytosis ofsecretory vesicles in pancreas. Where are these glyco-proteins synthesized?Describe the complete molecular pathway leading to their secretion at the

plasma membrane (in detail).

5 IF the terminal sugar on a glycoprotein or a glycolipid is a Mannose thathas been phosphorylated at the C6 position the cargo will be bound to a M6Preceptor. The fate of this cargo is.

6 In which cellular organelle are the TIM23 and TOM complexes found?

7 Describe the organelle import mechanism where heat shock proteins and

chaperoning are required.

8 The endogenous GTPase activity of Monomeric G-proteins serves to:

9 All GTP binding require GEFS and GAPs to complete their functionalcycles. Describe in detail how Ras is activated and how Transducin isactivated.

10 The low-density-lipoprotein particle transports cholesterol in the

circulatory system. Why do we need the lipoprotein component? Describethe molecular mechanism of cholesterol uptake. What is the ultimate fates ofthe receptor and the cholesterol?

11 Inclusion-cell (I-cell) disease is an organelle storage disease and resultsfrom a defective phosphotransferase in the Golgi apparatus. This enzymetransfers phosphate to mannose residues target proteins.

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12 The affected organelles contain very dense inclusion bodies comprised ofaggregated lipids, proteins, carbohydrates and nucleic acids. What is the roleof phosphate in a normal person and how does this avoid formation ofinclusion bodies?

13 Unlike the Mitochondrial import mechanism transport of proteins throughthe ER bilayer does not require chaperonins. Why?

14 If you were developing a molecular tool to block viral entry into cellswhich vesicle forming domains would you target and describe 4 specificcomponents that if inactivated could stop viral entry.

15 Describe the molecular components required for targeting, transport and

fusion of cargo laden traffic to its intended destination.