CELL BIO EXAM 2 {QUIZ QUESTIONS +
iCLICKER} 180 QUESTIONS AND
CORRECT ANSWERS 2025
Which of the following is not an important ER-resident enzyme that modifies
proteins in the secretory pathway?
oligosaccharyl transferase
protein disulfide isomerase
Sec61
BiP - ANSWER- Sec61
Which of the following statements regarding clathrin-coated vesicles is FALSE?
-Adapter complexes provide the specificity of vesicle cargo.
-Clathrin-coated vesicle assembly is mediated by the GTPase ARF.
-Membrane proteins containing a Tyr-X-X-Φ sequence are recruited into
clathrin/AP3 coats.
-Dynamin is required for pinching off clathrin-coated vesicles. - ANSWER-
Membrane proteins containing a Tyr-X-X-Φ sequence are recruited into
clathrin/AP3 coats.
,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?
-Ribosomes and mRNA are incubated with microsomes, then a protease is added
and the results are analyzed.
-Ribosomes and mRNA are incubated with microsomes, then a protease and
detergent are added and the results are analyzed.
-Ribosomes and mRNA are incubated with protease, then microsomes are added
and the results are analyzed.
-Ribosomes and mRNA are incubated with microsomes, then detergent is added
and the results are analyzed. - ANSWER- Ribosomes and mRNA are incubated
with microsomes, then a protease is added and the results are analyzed.
A transmembrane receptor that functions at the cell membrane has an exoplasmic
N-terminal sequence, a signal-anchor sequence, and a stop-transfer-anchor
sequence. This protein was first inserted into the membrane where?
-at the plasma membrane
-in the cis-Golgi
-in the late endosome
-in the ER - ANSWER- in the ER
Endoglycosidase D is a useful reagent because it allows scientists to distinguish
glycosylated proteins that:
-remain in the cis-Golgi.
-remain in the trans-Golgi.
-remain in the ER.
-get secreted. - ANSWER- remain in the ER
Vesicle budding recruits proteins that are needed for subsequent:
,-invagination of the vesicle into the ER lumen.
-selective vesicle targeting and fusion.
-shedding of integral membrane proteins into the cytosol.
-assembly of chromosome folding machinery. - ANSWER- selective vesicle
targeting and fusion.
The presence of clathrin mediates vesicular transport:
-from ER to cis-Golgi.
-from trans-Golgi to endosome.
-from nuclear membrane to endosome.
-from plasma membrane to trans-Golgi. - ANSWER- from trans-Golgi to
endosome.
Which small GTPase is NOT involved in vesicle budding or docking?
-ARF
-rab1
-ras
-Sar1p - ANSWER- ras
What phenotype would be observed in a cell containing a nonhydrolyzable form of
ATP with respect to the vesicles of the secretory pathway?
-Secretion of peptides from the cell would be increased.
-Vesicles would be delivered to incorrect target membranes.
-Uncoated vesicles would accumulate.
-Coated vesicles would accumulate. - ANSWER- Coated vesicles would
accumulate.
, Lipoproteins are effective in transporting lipid molecules in an aqueous
environment because their surface layer is:
-hydrophobic.
-glycosidic.
-amphipathic.
-hydrophobic and glycosidic. - ANSWER- amphipathic
Post-translational translocation of some secretory proteins in yeast is powered by:
-ATP hydrolysis by BiP.
-cAMP hydrolysis by cAMP phosphodiesterase.
-GTP hydrolysis EF-Tu.
-phospholipid hydrolysis by phospholipase C. - ANSWER- ATP hydrolysis by
BiP.
The topology of membrane proteins can often be predicted by computer programs
that identify_____ topogenic segments.
-glycosylation-specific
-hydrophilic
-hydrophobic
-cleavable signal sequence - ANSWER- hydrophobic
All the following proteins interact with exposed amino acids during protein folding
in the ER EXCEPT:
-BiP.
-calnexin.
-PDI.
-prolyl isomerase. - ANSWER- calnexin
iCLICKER} 180 QUESTIONS AND
CORRECT ANSWERS 2025
Which of the following is not an important ER-resident enzyme that modifies
proteins in the secretory pathway?
oligosaccharyl transferase
protein disulfide isomerase
Sec61
BiP - ANSWER- Sec61
Which of the following statements regarding clathrin-coated vesicles is FALSE?
-Adapter complexes provide the specificity of vesicle cargo.
-Clathrin-coated vesicle assembly is mediated by the GTPase ARF.
-Membrane proteins containing a Tyr-X-X-Φ sequence are recruited into
clathrin/AP3 coats.
-Dynamin is required for pinching off clathrin-coated vesicles. - ANSWER-
Membrane proteins containing a Tyr-X-X-Φ sequence are recruited into
clathrin/AP3 coats.
,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?
-Ribosomes and mRNA are incubated with microsomes, then a protease is added
and the results are analyzed.
-Ribosomes and mRNA are incubated with microsomes, then a protease and
detergent are added and the results are analyzed.
-Ribosomes and mRNA are incubated with protease, then microsomes are added
and the results are analyzed.
-Ribosomes and mRNA are incubated with microsomes, then detergent is added
and the results are analyzed. - ANSWER- Ribosomes and mRNA are incubated
with microsomes, then a protease is added and the results are analyzed.
A transmembrane receptor that functions at the cell membrane has an exoplasmic
N-terminal sequence, a signal-anchor sequence, and a stop-transfer-anchor
sequence. This protein was first inserted into the membrane where?
-at the plasma membrane
-in the cis-Golgi
-in the late endosome
-in the ER - ANSWER- in the ER
Endoglycosidase D is a useful reagent because it allows scientists to distinguish
glycosylated proteins that:
-remain in the cis-Golgi.
-remain in the trans-Golgi.
-remain in the ER.
-get secreted. - ANSWER- remain in the ER
Vesicle budding recruits proteins that are needed for subsequent:
,-invagination of the vesicle into the ER lumen.
-selective vesicle targeting and fusion.
-shedding of integral membrane proteins into the cytosol.
-assembly of chromosome folding machinery. - ANSWER- selective vesicle
targeting and fusion.
The presence of clathrin mediates vesicular transport:
-from ER to cis-Golgi.
-from trans-Golgi to endosome.
-from nuclear membrane to endosome.
-from plasma membrane to trans-Golgi. - ANSWER- from trans-Golgi to
endosome.
Which small GTPase is NOT involved in vesicle budding or docking?
-ARF
-rab1
-ras
-Sar1p - ANSWER- ras
What phenotype would be observed in a cell containing a nonhydrolyzable form of
ATP with respect to the vesicles of the secretory pathway?
-Secretion of peptides from the cell would be increased.
-Vesicles would be delivered to incorrect target membranes.
-Uncoated vesicles would accumulate.
-Coated vesicles would accumulate. - ANSWER- Coated vesicles would
accumulate.
, Lipoproteins are effective in transporting lipid molecules in an aqueous
environment because their surface layer is:
-hydrophobic.
-glycosidic.
-amphipathic.
-hydrophobic and glycosidic. - ANSWER- amphipathic
Post-translational translocation of some secretory proteins in yeast is powered by:
-ATP hydrolysis by BiP.
-cAMP hydrolysis by cAMP phosphodiesterase.
-GTP hydrolysis EF-Tu.
-phospholipid hydrolysis by phospholipase C. - ANSWER- ATP hydrolysis by
BiP.
The topology of membrane proteins can often be predicted by computer programs
that identify_____ topogenic segments.
-glycosylation-specific
-hydrophilic
-hydrophobic
-cleavable signal sequence - ANSWER- hydrophobic
All the following proteins interact with exposed amino acids during protein folding
in the ER EXCEPT:
-BiP.
-calnexin.
-PDI.
-prolyl isomerase. - ANSWER- calnexin
