How does a guanine nucleotide exchange factor (GEF) activate a GTP-binding protein?

Which experimental approach best tests whether a specific signal sequence is sufficient to direct a protein to the ER?

A researcher expresses a modified transmembrane protein with its stop-transfer sequence deleted. What is the most likely outcome?

Two different cell types are exposed to the same signaling molecule, but they respond differently. Which scenario best explains this observation?

A mutation blocks formation of mannose-6-phosphate. What outcome is most likely?

What ensures the release of iron from transferrin in receptor-mediated endocytosis?

A researcher knocks out the gene for v-ATPase. Which defect is most likely to occur?

What is the role of lysosomal membrane glycoproteins?

What would be the consequence of a kinase that cannot be turned off?

Which best explains how specificity is achieved in vesicle docking?