Endoplasmic reticulum Knowledge-Based Download PDF

Questions

1. 1.

   Which molecular feature directs a ribosome translating a secretory or membrane-bound protein to dock onto the membrane of the rough endoplasmic reticulum?

   • A) A 5' 7-methylguanosine cap
   • B) An amino-terminal hydrophobic signal peptide
   • C) A mannose-6-phosphate recognition tag
   • D) An internal nuclear localization signal
2. 2.

   Which of the following events occurs within the lumen of the rough endoplasmic reticulum during the maturation of newly synthesized polypeptides?

   • A) Addition of a 5' methylguanosine cap to the amino terminus
   • B) Phosphorylation of mannose residues to direct enzymes to lysosomes
   • C) Attachment of O-linked oligosaccharides to serine and threonine residues
   • D) Chaperone-assisted protein folding and formation of disulfide bonds
3. 3.

   Proteins synthesized by ribosomes attached to the rough endoplasmic reticulum are packaged into transport vesicles and typically delivered next to which cellular structure for further processing and sorting?

   • A) Nucleolus
   • B) Peroxisome
   • C) Mitochondrion
   • D) Golgi apparatus
4. 4.

   In eukaryotic cells, the membrane of the rough endoplasmic reticulum is directly continuous with which of the following structures?

   • A) The outer membrane of the nuclear envelope
   • B) The cis cisternae of the Golgi apparatus
   • C) The inner membrane of the mitochondrion
   • D) The phospholipid bilayer of the plasma membrane
5. 5.

   Which of the following cellular processes is primarily performed by the smooth endoplasmic reticulum rather than the rough endoplasmic reticulum?

   • A) Synthesis of proteins destined for incorporation into the plasma membrane
   • B) Attachment of ribosomes to facilitate the translation of secretory polypeptides
   • C) Biosynthesis of lipids and detoxification of harmful metabolic byproducts
   • D) Processing and assembly of ribosomal RNA subunits prior to nuclear export