Lodish Ch 13 TB MC

Which of the following proteins involved in cotranslational translocation of proteins into the ER membrane is NOT a GTP-hydrolyzing protein?

Protein insertion into the mammalian ER membrane is typically:

Post-translational translocation of some secretory proteins in yeast is powered by:

In the absence of targeting information, what is the default location of proteins synthesized on cytosolic ribosomes?

In a cell-free protein synthesis system utilizing microsomes from fragmented ER, under which condition could you determine if the new protein was imported into the microsome?

Which of the following is true about ER import?

Type I membrane proteins have all of the following properties, except:

GPI-anchoring serves a special function, especially in polarized epithelial cells, because this modification serves to target proteins to the:

The topology of membrane proteins can often be predicted by computer programs that identify ______ topogenic segments.

Glycosylation, a post-translational modification of proteins, occurs in the:

All the following proteins interact with exposed amino acids during protein folding in the ER, except:

Unassembled or misfolded proteins in the RER can be damaging to the physiology of a cell and therefore are transported to the cytosol where they are degraded. This transport process is referred to as:

Sorting of proteins to mitochondria and chloroplasts is:

Tom/Tim and Toc/Tic protein complexes are involved in:

Protein sequences for targeting to mitochondria or chloroplasts are located at:

Protein import into the mitochondrial matrix is supported by energy input from:

A polypeptide chain contains an amphipathic helix, with arginine and lysine residues on one side and hydrophobic residues on the other. It will likely enter:

In a cell that lacks cytosolic Hsc70:

Which of the following components of mitochondrial import are NOT required for a sequence containing a matrix-targeting sequence and an intermembrane-space-targeting sequence?

Many peroxisomal matrix proteins are imported as:

PTS1- and PTS2-bearing matrix proteins are targeted to:

Unlike mitochondria and chloroplasts, peroxisomes can arise ______ from precursor membranes, as well as by division of preexisting organelles.

The nuclear pore complex allows for:

During the import of proteins into the nucleus, the importin subunit binds directly to:

Which type of RNA participates in nuclear export of mRNA?

Which of the following is present in the nuclear export sequence of PKI (an inhibitor of protein kinase A)?

Transport of unspliced HIV mRNA from the nucleus to the cytoplasm of host cells is promoted by a virus-encoded protein named:

How does Ran-GTP participate in the nuclear export of the HIV Rev protein?

The nuclear pore complex (NPC) contains ______ structures that form a gel-like matrix that allow small molecules to diffuse through, but require larger proteins to enter via importin or other nuclear chaperones.

During the process of nuclear import, a GEF works in the:

In multipass membrane proteins synthesized in association with membrane-bounded ribosomes of the rough ER, signal-anchor and stop-transfer anchor sequences alternate. What do these sequences do?

Having misfolded soluble or secretory proteins in the RER contributes to what investigators call the “traffic jam,” a scenario associated with a number of human diseases where the normal transport of proteins is blocked by these abnormal proteins and the inability of protein complexes to arrive at their correct site and function properly. Briefly describe how the cell overcomes this particular traffic jam by exporting the misfolded proteins out of the RER into the cytosol, where they are degraded by the proteasome.

What are the general features of an N-terminal signal sequence that targets secretory proteins to the ER?

In the absence of targeting information, what is the default location of proteins synthesized on cytosolic ribosomes?

How does Ran·GTP participate in the nuclear export of the HIV Rev protein?

To what extent do peroxisomal matrix protein import and peroxisomal membrane protein import share the same machinery?

What is meant by de novo formation of peroxisomes?

What is the meaning of “quality control in the ER?”

Why are bacteria often a poor choice for the production of proteins for therapeutic purposes?

During in vitro translation of mitochondrially targeted proteins, when must mitochondria be added for import of proteins synthesized on cytosolic ribosomes?

How are proteins imported into the thylakoids of chloroplasts?