Cell 201, Midterm 2
Comprehensive Questions
with Verified Answers
Graded A+
1. ER cisternae Answer: flattened sac of the endoplasmic reticulum
2. Retrograde Transport (Endomembrane) Answer: Inward vesicle movement
3. Anterograde Transport (Endomembrane) Answer: Outward vesicle movement
4. Transitional ER Answer: A subdomain of rough ER where vesicles are formed for transport of
lipids and proteins from
the ER to the Golgi
5. Functions of the Smooth ER Answer: lipid synthesis, carbohydrate metabolism, drug
detoxification, and calcium storage
6. Drug detoxification Answer: Involves hydroxylation to increase solubility and excrete from the
body. This does not ettect detox in the brain, as hydrophillic compounds can't cross the BBB
7. Glucose-6-phsophatase Answer: An enzyme of the sER the hydrolyzes glucose-6-
phosphate into free glucose. means sER is abundant in liver cells
8. Golgi stack Answer: A series of 3-8 cisternae of the Golgi apparatus
,9. CGN Answer: Cis-Golgi network, faces the ER
10. TGN Answer: Trans-Golgi Network, faces the cell membrane
11. Medial cisternae Answer: Parts of the Golgi between the CGN and TGN
12. N-glycoslyation Answer: Addition of an oligosaccharide to the nitrogen atom of
asparagine residues
13. O-glycosylation Answer: Addition of an oligosaccharide to the oxygen atom of a hydroxyl
group on serine or
threonine residues
14. Core oligosaccharide Answer: two N-acetylglucosamine, nine manose, and three
glucose
15. Calnexin/Calreticulin Answer: Chaperones that bind to monoglycosylated proteins and
promote disulfide bond
formation
16. Glucosidase I and II Answer: Enzymes that cleave glucose residue from
glycosylated proteins. Glucosidase II cleaves the final glucose from a glycoprotein
17. Glucosyl transferase Answer: ER enzyme that adds a single glucose back to an
improperly folded protein to make it a substrate for Calnexin or Calreticulin
18. ER Mannosidase Answer: An enzyme that removes a mannose from a glycoprotein to
trigger ERAD
19. Constitutive Secretion Answer: Unregulated and continuous secretion independent o
signals (e.g., mucous in
the intestinal lining)
20. Regulated Secretion Answer: Secretion from an accumulation of vesicles at the
plasma membrane triggered by specific signals (e.g., neurotransmitter release)
, 21. Mutant Screening and the Secretory Pathway Answer: 1. Apply mutagen to
yeast cells and incubate
2. Replicate the dish by pressing fabric onto it and transferring to another plate
3. Test for temperature sensitive mutations in the replicate by heating the plate and looking for cells
with overfilled organelles
22. ER Retention tags Answer: RXR (Arg-X-Arg) or KK (Lys-Lys)
23. ER Retrieval Tags Answer: KDEL (mammals) or HDEL (yeast)
24. Golgi-specific proteins Answer: Integral membrane proteins with one or more
transmembrane sequences
The length of this sequence will determine which cisternae it is embedded in (CGN-5 nm, TGN-8nm)
25. Polarized Secretion Answer: Exocytosis of specific proteins is limited to a specific
surface of the cell
26. Phagocytosis Answer: The ingestion of large particles, including whole cells or
microorganisms. Performed by
Neutrophils and macrophages
27. Clathrin Answer: A triskelion coat protein involved in endocytosis with associated adaptor
proteins
28. COPI Answer: A coat protein involved in retrograde movement toward the ER
29. COPII Answer: A coat protein involved in anterograde transport toward the Golgi
30. Dynamin Answer: A cytosolic GTPase that tightens around the neck of a clathrin-coated
vesicle as GTP is hydrolyzed
31. Ras GTPases Answer: A family of GTPases that initiate COPI and COPII vesicle formation.
Comprehensive Questions
with Verified Answers
Graded A+
1. ER cisternae Answer: flattened sac of the endoplasmic reticulum
2. Retrograde Transport (Endomembrane) Answer: Inward vesicle movement
3. Anterograde Transport (Endomembrane) Answer: Outward vesicle movement
4. Transitional ER Answer: A subdomain of rough ER where vesicles are formed for transport of
lipids and proteins from
the ER to the Golgi
5. Functions of the Smooth ER Answer: lipid synthesis, carbohydrate metabolism, drug
detoxification, and calcium storage
6. Drug detoxification Answer: Involves hydroxylation to increase solubility and excrete from the
body. This does not ettect detox in the brain, as hydrophillic compounds can't cross the BBB
7. Glucose-6-phsophatase Answer: An enzyme of the sER the hydrolyzes glucose-6-
phosphate into free glucose. means sER is abundant in liver cells
8. Golgi stack Answer: A series of 3-8 cisternae of the Golgi apparatus
,9. CGN Answer: Cis-Golgi network, faces the ER
10. TGN Answer: Trans-Golgi Network, faces the cell membrane
11. Medial cisternae Answer: Parts of the Golgi between the CGN and TGN
12. N-glycoslyation Answer: Addition of an oligosaccharide to the nitrogen atom of
asparagine residues
13. O-glycosylation Answer: Addition of an oligosaccharide to the oxygen atom of a hydroxyl
group on serine or
threonine residues
14. Core oligosaccharide Answer: two N-acetylglucosamine, nine manose, and three
glucose
15. Calnexin/Calreticulin Answer: Chaperones that bind to monoglycosylated proteins and
promote disulfide bond
formation
16. Glucosidase I and II Answer: Enzymes that cleave glucose residue from
glycosylated proteins. Glucosidase II cleaves the final glucose from a glycoprotein
17. Glucosyl transferase Answer: ER enzyme that adds a single glucose back to an
improperly folded protein to make it a substrate for Calnexin or Calreticulin
18. ER Mannosidase Answer: An enzyme that removes a mannose from a glycoprotein to
trigger ERAD
19. Constitutive Secretion Answer: Unregulated and continuous secretion independent o
signals (e.g., mucous in
the intestinal lining)
20. Regulated Secretion Answer: Secretion from an accumulation of vesicles at the
plasma membrane triggered by specific signals (e.g., neurotransmitter release)
, 21. Mutant Screening and the Secretory Pathway Answer: 1. Apply mutagen to
yeast cells and incubate
2. Replicate the dish by pressing fabric onto it and transferring to another plate
3. Test for temperature sensitive mutations in the replicate by heating the plate and looking for cells
with overfilled organelles
22. ER Retention tags Answer: RXR (Arg-X-Arg) or KK (Lys-Lys)
23. ER Retrieval Tags Answer: KDEL (mammals) or HDEL (yeast)
24. Golgi-specific proteins Answer: Integral membrane proteins with one or more
transmembrane sequences
The length of this sequence will determine which cisternae it is embedded in (CGN-5 nm, TGN-8nm)
25. Polarized Secretion Answer: Exocytosis of specific proteins is limited to a specific
surface of the cell
26. Phagocytosis Answer: The ingestion of large particles, including whole cells or
microorganisms. Performed by
Neutrophils and macrophages
27. Clathrin Answer: A triskelion coat protein involved in endocytosis with associated adaptor
proteins
28. COPI Answer: A coat protein involved in retrograde movement toward the ER
29. COPII Answer: A coat protein involved in anterograde transport toward the Golgi
30. Dynamin Answer: A cytosolic GTPase that tightens around the neck of a clathrin-coated
vesicle as GTP is hydrolyzed
31. Ras GTPases Answer: A family of GTPases that initiate COPI and COPII vesicle formation.
