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UBC BIOL 200 CH 5 2026 LATEST
QUESTIONS AND ANSWERS| ACE
YOUR GRADES.
Proteins destined for the constitutive secretory pathway ___. -
correct answer -do not aggregate in the TGN.
The regulated exocytosis pathway operates in cells specialized
for secretion and produces cell product on demand. - correct
answer -True.
Discuss autoradiography: - correct answer -You follow
radioactively labeled proteins through the secretory process.
Discuss cell fractionation: - correct answer -You grind up cells +
look at what is found in each of the components separately.
Discuss a continuous labeling experiment: - correct answer -
Feed the cells with a radioactively-labled precursor, lyse +
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homogenize the cell after certain times, centrifuge and assay.
Then look for the protein of interest.
Discuss a pulse-chase experiment: - correct answer -Feed the
cell radioactive material for a set time and then remove it and feed
them the same nutrient but not radioactive. Then follow the
labeled targets as they move (or dont) throughout the cell.
What does mannose-6-phosphate on a protein do? - correct
answer -It targets it to a lysosome. The mannose-6-phosphate is
a targeting sequence.
What recognizes the mannose-6-phosphate? - correct answer -
the mannose-6-phosphate receptors in the trans Golgi.
Proteins with mannose-6-phosphate that are attached to the TGN
receptor concentrate and are packaged into clathrin-coated
vesicles. What happens next? - correct answer -They are sent to
the endosome. The mannose-6-phosphate cleaves off (b/c pH is
too high in the endosome). The lysosomal protein then travels
with the endosome to the lysosome and the mannose-6-
phosphate is recycled to the TGN.
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Lysosomes have a pH of 5. Maintained by proton pumps. -
correct answer -The membane of the lysosome is resistant to
action of its own digestive enzymes due to extensive glycosylation
of the proteins on the lumen side of the membrane.
Primary Lysosome = ?
Secondary Lysosome = ? - correct answer -Primary = newly
made, unused
Secondary = has fused with an endosome at least once.
Define Phagocytosis - correct answer -The ingestion of large
particles by cells. Occurs in response to activation of cell-surface
receptors.
Define Pinocytosis - correct answer -The ingestion of fluid and
macromolecules via small vesicles
Define receptor-mediated endocytosis - correct answer -the
ingestion of specific molecules that are bound to receptors on the
cell surface. Clathrin-coated.
UBC BIOL 200 CH 5 2026 LATEST
QUESTIONS AND ANSWERS| ACE
YOUR GRADES.
Proteins destined for the constitutive secretory pathway ___. -
correct answer -do not aggregate in the TGN.
The regulated exocytosis pathway operates in cells specialized
for secretion and produces cell product on demand. - correct
answer -True.
Discuss autoradiography: - correct answer -You follow
radioactively labeled proteins through the secretory process.
Discuss cell fractionation: - correct answer -You grind up cells +
look at what is found in each of the components separately.
Discuss a continuous labeling experiment: - correct answer -
Feed the cells with a radioactively-labled precursor, lyse +
, Page | 2
homogenize the cell after certain times, centrifuge and assay.
Then look for the protein of interest.
Discuss a pulse-chase experiment: - correct answer -Feed the
cell radioactive material for a set time and then remove it and feed
them the same nutrient but not radioactive. Then follow the
labeled targets as they move (or dont) throughout the cell.
What does mannose-6-phosphate on a protein do? - correct
answer -It targets it to a lysosome. The mannose-6-phosphate is
a targeting sequence.
What recognizes the mannose-6-phosphate? - correct answer -
the mannose-6-phosphate receptors in the trans Golgi.
Proteins with mannose-6-phosphate that are attached to the TGN
receptor concentrate and are packaged into clathrin-coated
vesicles. What happens next? - correct answer -They are sent to
the endosome. The mannose-6-phosphate cleaves off (b/c pH is
too high in the endosome). The lysosomal protein then travels
with the endosome to the lysosome and the mannose-6-
phosphate is recycled to the TGN.
, Page | 3
Lysosomes have a pH of 5. Maintained by proton pumps. -
correct answer -The membane of the lysosome is resistant to
action of its own digestive enzymes due to extensive glycosylation
of the proteins on the lumen side of the membrane.
Primary Lysosome = ?
Secondary Lysosome = ? - correct answer -Primary = newly
made, unused
Secondary = has fused with an endosome at least once.
Define Phagocytosis - correct answer -The ingestion of large
particles by cells. Occurs in response to activation of cell-surface
receptors.
Define Pinocytosis - correct answer -The ingestion of fluid and
macromolecules via small vesicles
Define receptor-mediated endocytosis - correct answer -the
ingestion of specific molecules that are bound to receptors on the
cell surface. Clathrin-coated.
