Following statements are regarding to the CFTR.

A. cystic fibrosis transmembrane conductance regulator allows Cl− ions to flow out of the cell, following their concentration gradient.

B. ATP binding to CFTR’s two nucleotide-binding domains appears to close the Cl− channel, and the hydrolysis of one ATP opens it (the other ATP remains intact).

C. the CFTR channel can open only if its regulatory domain (which is unique among ABC transporters) has been phosphorylated, thus regulating the flow of ions across the membrane.

D. The maintenance of electrical neutrality requires that the Cl− ions transported by the CFTR be accompanied by positively charged ions, mainly Na+. The transported ions are osmotically accompanied by water, thus maintaining the proper level of fluidity in secretions of the airways, intestinal tract, and the ducts of the pancreas, testes, and sweat glands.

Which of the following combination is correct?

#Question id: 4283

#Unit 3. Fundamental Processes

Proteins can enter which organelle(s) in their folded conformation?

#Question id: 4284

#Unit 3. Fundamental Processes

Assays for following the trafficking of proteins through the secretory pathway in living cells require

a. sensitive methods to distinguish the very small differences in organelle density caused by passage of a wave of protein transport through the organelle.

b. a way to identify compartments where labeled proteins are located.

c. the use of cell types that are highly dedicated secretory cells.

d. the use of enucleate cells in order to eliminate the nucleus as a site of labeling.

e. a way to label a cohort of secretory proteins

#Question id: 4285

#Unit 3. Fundamental Processes

VSV G protein has been a very useful tracker protein for both living cell and in vitro assays because

#Question id: 4286

#Unit 3. Fundamental Processes

Transport vesicles

a. can have a clathrin coat.     b. can be coated with a heteromeric COPI and COPII coat.

c. can contain assembly proteins.

d. can shuttle proteins from mitochondria to the endoplasmic reticulum.

e. can fuse with target organelles.

#Question id: 4287

#Unit 3. Fundamental Processes

How the mTOR pathway increases the protein synthesis?

#Question id: 4288

#Unit 3. Fundamental Processes

During eukaryotic protein synthesis, stress conditions result in activation of specific kinases leading to phosphorylation of a key translation initiation factor that inhibits protein synthesis from a large number of cellular mRNA. Which one of the following factors is the kinase?