Question 1

When compared to polypeptides synthesized in vitro on free ribosomes, polypeptides synthesized from the same mRNA on microsome-bound ribosomes often are

Accepted Answer

A)   the same size.
B)   larger.
C)   smaller.
D)   more hydrophobic.E) None of the above
F) A) and B)

Question 2

The process by which cells degrade their own components by enclosing them in ER membrane is

Accepted Answer

A)   autophagy.
B)   ER-mediated endocytosis.
C)   phagocytosis.
D)   pinocytosis.E) A) and B)
F) A) and C)

Question 3

The sequence Lys-Asp-Glu-Leu (KDEL)  serves to retain proteins in the ER by

Accepted Answer

A)   preventing their packaging into vesicles destined for the Golgi.
B)   binding to receptors within the membranes of the ERGIC and Golgi, which retain them or return them to the ER.
C)   binding the SRP receptor in the ER membrane.
D)   associating with the lipids in the ER membrane.E) B) and D)
F) A) and B)

Question 4

Cargo proteins are transported through the Golgi apparatus to the trans-Golgi network, where they are sorted into various vesicles that are targeted to different destinations. What is the role of vesicles in cargo protein transport through the Golgi apparatus?

Accepted Answer

Two general models for Golgi function in...

Question 5

A member of the heat-shock class of proteins, BiP, is necessary for the proper folding of proteins in the ER. In terms of function, what do BiP and the heat-shock proteins (HSP) have in common?

Accepted Answer

The primary function of heat-shock prote...

Question 6

How do lysosomes become acidic?

Accepted Answer

Proton pumps are targeted to l...

Question 7

The major model of vesicle fusion holds that actual fusion of a vesicle with its target membrane is driven by the interaction of pairs of proteins called vesicle and target

Accepted Answer

A)   SNAREs.
B)   Rab proteins.
C)   COPs.
D)   tethers.E) None of the above
F) A) and B)

Question 8

Free ribosomes in the cytosol and ribosomes bound to the ER membrane have

Accepted Answer

A)   different types of large and small subunits.
B)   the same types of large and small subunits.
C)   different types of large subunits but the same small subunits.
D)   different types of small subunits but the same large subunits.E) B) and D)
F) A) and B)

Question 9

In eukaryotic cells, most protein synthesis is initiated in the _______.

Accepted Answer

The answer of In eukaryotic cells, most protein synthesis is...

Question 10

Proteins that fail to fold properly in the endoplasmic reticulum are removed through the process of _______.

Accepted Answer

ERAD (ER-a...

Question 11

Cargo proteins are transported through the Golgi apparatus by

Accepted Answer

A)   forward (anterograde)  moving vesicles.
B)   backward (retrograde)  moving vesicles.
C)   cisternal maturation in which the cisternae themselves are the carriers for cargo transport through the Golgi apparatus.
D)   some process that remains controversial and may include elements of both vesicular transport and cisternal maturation.E) B) and C)
F) All of the above

Question 12

Arf function on vesicles is regulated by

Accepted Answer

A)   phosphorylation of serine residues.
B)   phosphorylation of mannose residues.
C)   binding of GTP.
D)   binding of ATP.E) A) and C)
F) None of the above

Question 13

The cytosolic surface of the rough endoplasmic membrane can be readily distinguished from the luminal surface by the presence of _______.

Accepted Answer

The answer of The cytosolic surface of the rough endoplasmic...

Question 14

Phospholipids are synthesized in the cytosolic half of the ER bilayer.

Accepted Answer

A) True 
 B)False

Question 15

Using radiolabeled amino acids, Palade and colleagues defined the pathway taken by secreted proteins. Which sequence represents that pathway?

Accepted Answer

A)   Rough ER  →\rightarrow→  smooth ER  →\rightarrow→  Golgi  →\rightarrow→  secretory vesicles  →\rightarrow→ cell exterior
B)   Rough ER  →\rightarrow→  smooth ER  →\rightarrow→  Golgi  →\rightarrow→  endosomes  →\rightarrow→ cell exterior
C)   Rough ER  →\rightarrow→  Golgi  →\rightarrow→  lysosomes  →\rightarrow→  cell exterior
D)   Rough ER  →\rightarrow→  Golgi  →\rightarrow→  secretory vesicles  →\rightarrow→  cell exterior E) A) and B)
F) C) and D)

Question 16

Smooth ER is abundant in cells actively synthesizing steroid hormones.

Accepted Answer

A) True 
 B)False

Question 17

What are the two families of small GTP-binding proteins that are involved in the formation of coated vesicles?

Accepted Answer

Rab protei...

Question 18

The pH inside lysosomes is about

Accepted Answer

A)   7.0.
B)   6.0.
C)   5.0.
D)   4.0.E) B) and D)
F) A) and D)

Question 19

Describe the selective and nonselective cellular purposes of autophagy.

Accepted Answer

Most cellular proteins degraded by autop...

Question 20

Describe the process of autophagy.

Accepted Answer

Autophagy is the process by wh...

Exam 12: Protein Sorting and Transport

Arf function on vesicles is regulated by

Correct AnswerverifiedShow Answer

The pH inside lysosomes is about

Correct AnswerverifiedShow Answer

In eukaryotic cells, most protein synthesis is initiated in the _______.

Correct AnswerverifiedShow Answer

Cargo proteins are transported through the Golgi apparatus by

Correct AnswerverifiedShow Answer

When compared to polypeptides synthesized in vitro on free ribosomes, polypeptides synthesized from the same mRNA on microsome-bound ribosomes often are

Correct AnswerverifiedShow Answer

A member of the heat-shock class of proteins, BiP, is necessary for the proper folding of proteins in the ER. In terms of function, what do BiP and the heat-shock proteins (HSP) have in common?

Correct AnswerverifiedThe primary function of heat-shock prote...View AnswerShow Answer

The sequence Lys-Asp-Glu-Leu (KDEL) serves to retain proteins in the ER by

Correct AnswerverifiedShow Answer

Cargo proteins are transported through the Golgi apparatus to the trans-Golgi network, where they are sorted into various vesicles that are targeted to different destinations. What is the role of vesicles in cargo protein transport through the Golgi apparatus?

Correct AnswerverifiedTwo general models for Golgi function in...View AnswerShow Answer

Proteins that fail to fold properly in the endoplasmic reticulum are removed through the process of _______.

Correct AnswerverifiedERAD (ER-a...View AnswerShow Answer

The process by which cells degrade their own components by enclosing them in ER membrane is

Correct AnswerverifiedShow Answer

The major model of vesicle fusion holds that actual fusion of a vesicle with its target membrane is driven by the interaction of pairs of proteins called vesicle and target

Correct AnswerverifiedShow Answer

What are the two families of small GTP-binding proteins that are involved in the formation of coated vesicles?

Correct AnswerverifiedRab protei...View AnswerShow Answer

How do lysosomes become acidic?

Correct AnswerverifiedProton pumps are targeted to l...View AnswerShow Answer

Describe the selective and nonselective cellular purposes of autophagy.

Correct AnswerverifiedMost cellular proteins degraded by autop...View AnswerShow Answer

Phospholipids are synthesized in the cytosolic half of the ER bilayer.

Correct AnswerverifiedShow Answer

The cytosolic surface of the rough endoplasmic membrane can be readily distinguished from the luminal surface by the presence of _______.

Correct AnswerverifiedShow Answer

Smooth ER is abundant in cells actively synthesizing steroid hormones.

Correct AnswerverifiedShow Answer

Free ribosomes in the cytosol and ribosomes bound to the ER membrane have

Correct AnswerverifiedShow Answer

Using radiolabeled amino acids, Palade and colleagues defined the pathway taken by secreted proteins. Which sequence represents that pathway?

Correct AnswerverifiedShow Answer

Describe the process of autophagy.

Correct AnswerverifiedAutophagy is the process by wh...View AnswerShow Answer

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The primary function of heat-shock prote...
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Two general models for Golgi function in...
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Correct Answer
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ERAD (ER-a...
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Correct Answer
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Correct Answer
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Rab protei...
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Proton pumps are targeted to l...
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Most cellular proteins degraded by autop...
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Autophagy is the process by wh...
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