Exam 8: Cytoplasmic Membrane Systems: Structure, function, and Membrane Trafficking

Cells are infected with a virus carrying a temperature-sensitive mutant VSVG gene that encodes a protein that cannot leave the ER of infected cells grown at restrictive temperatures.Thus,at higher temperatures,______________.

What are the functions of housekeeping receptors in the endocytic pathway? What is the function of signaling receptors in the endocytic pathway? How do the fates of housekeeping and signaling receptors generally differ?

What is the general name for a molecule that physically links two different types of materials?

How and where is the asymmetry of the phospholipid bilayers initially established?

What is the primary adaptor protein of the COPII coat that interacts specifically with the ER export signals in the cytosolic tails of membrane proteins that are destined to traffic on to the Golgi complex?

What removes the stroma-targeting domain and where does the removal occur?

What allows the interface between the Sec13-Sec31 subunits to form cages of varying diameter,thus accommodating vesicles of varying size?

What is responsible for degrading misfolded proteins in the cytoplasm?

The accumulation of misfolded proteins in the ER is a potentially lethal situation and thus causes the triggering of what process?

You wish to target a purified enzyme to the lysosomes of macrophages.How might you accomplish this?

Which part of the Golgi complex is thought to function primarily as a sorting station that distinguishes between proteins to be shipped back to the ER and those that are allowed to proceed to the next Golgi station?

What is thought to direct the movement of vesicles through the cytoplasm to their final destination?

When Rabs have bound to GTP,what do they do?

What does the conformation-sensing enzyme UGGT do if it binds to a misfolded or incompletely folded glycoprotein?

The two separate (basic)categories of uptake of extracellular materials into cytoplasmic vesicles are ______ and ______.

A scientist isolates two specific mRNAs.One codes for the enzyme fowlase,an enzyme that is involved in digestion in chickadees; the other codes for the quail enzyme quailase that is involved in cellular carbohydrate metabolism.Both mRNAs are placed in a test tube with RER vesicles stripped of their ribosomes,free ribosomes and precursors for protein synthesis.When the protein synthesis reaction is complete,fowlase is found inside the vesicles; quailase is found in the liquid portion of the test tube outside the vesicles.What can one conclude about the two proteins?

What are the differences between early and late endosomes?

Cells are infected with a vesicular stomatitis virus (VSV)strain in which a viral gene (VSVG)is fused to the green fluorescent protein gene.When the chimeric protein is synthesized,what pathway does it follow from synthesis until it leaves the cell?

What enzyme transfers a block of sugars to asparagine residues of a polypeptide as it enters the RER?

Which endosomes are typically located in the more interior part of the cell,near the nucleus?