BIOL 4100 EXAM 2 STUDY GUIDE QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
Secretory and Endocytic pathway protein trafficking
transporting vesicles and transporting membrane and soluble proteins from one
membrane-bounded compartment to another. The transport vesicles collect cargo
proteins in membrane budding from a donor compartment and deliver the cargo
proteins to the next compartment by fusing with the target membrane.
Secretory Pathway
It involves the ER and is moving outward, your distributing soluble and membrane
proteins that are synthesized in the rough ER to the final destination at the cells surface,
this also includes secretion, and going into the lysosomes.It has two stages. ER to Golgi
to Cell Surface to Endosomes to Lysosomes
Endocytic Pathway
· moving inward or taking something up from outside of the cell, ingestion and
degradation of extracellular molecules, can involve a cell taking up a pathogen. Goes
from plasma membrane to endosomes to lysosomes
Golgi
Key player in the biosynthetic secretory and endocytic pathway
Functions of Golgi
receiving transport vesicles from the ER, modifying proteins by glycosylation, and
dispatching secretory proteins in vesicles bound for the extracellular space, PM (plasma
membrane), or lysosome
,Golgi Cis, or forming face
entry face where the proteins from the ER enter the Golgi
Golgi Trans face
exit face, where the proteins leave the Golgi and go into their destined place such as
secretory vesicles, plasma membrane, or lysosomes
How does the Golgi work?
delivers proteins to the cell exterior via vesicles by unregulated secretion, secretory
vesicles whose movement to the plasma membrane/cell exterior can be regulated
(regulated secretion), or endosomes that mature into lysosomes
Coat function
concentrate transport proteins into specialized patches, and mold the forming vesicle
into curved shape
What are the three major coat types?
COPI, COPII, and clathrin coats
The three major types of transport vesicles each have?
different types of protein coat that are formed by a reversible polymerization of a distinct
set of protein coat and subunit
COPII coat
sar1, and goes from ER to cis-Golgi, secretory, and anterograde transport
COPI coat
ARF, cis-Golgi to ER, Golgi to Golgi, Golgi to vesicles (to plasma membrane), Golgi
back to ER by retrograde transport)
Clathrin coats
, ARF, from trans-Golgi to Endosomes/lysosomes by endocytosis
What is vesicle budding initiated by?
I. GTP-binding protein (ARF, Sar) these two different proteins are involved with different
coat proteins
II. Binding of coat protein (clathrin, COP1, COPII)
III. Binding of Cargo (if the cargo membrane is bound) or binding of a cargo-receptor
protein (if the protein is soluble)
IV. Coat proteins shed as vesicle diffuses towards target, exposing v-SNARE
What happens when vesicle fusion occurs?
Newly exposed v-SNARE (vesicle) interact with t-SNARE (target) on target membrane
Interaction allows for docking and fusion of vesicle and target membranes
Early stages of the secretory pathway
Vesicle transport is occurring between the ER and cis-Golgi which is called the initial
transport stage of the secretory pathway. COPII-coated vesicles are transporting newly
synthesized proteins containing Golgi-targeting sequences in their cytosolic domain or
bound to such protein (anterograde/forward direction). ER to Golgi. COPI-coated
vesicles are carrying ER/Golgi-resident proteins in the retrograde/backward direction.
Golgi to ER. They function to retrieve v-SNARE proteins, membranes, and mis-sorted
ER-resident proteins
Later Stages of the Secretory Pathway
This occurs in the trans-Golgi network, and involves a distal sorting compartment that
sorts proteins into five different types of vesicles for transport to the plasma membrane,
endosomes, and lysosomes
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
Secretory and Endocytic pathway protein trafficking
transporting vesicles and transporting membrane and soluble proteins from one
membrane-bounded compartment to another. The transport vesicles collect cargo
proteins in membrane budding from a donor compartment and deliver the cargo
proteins to the next compartment by fusing with the target membrane.
Secretory Pathway
It involves the ER and is moving outward, your distributing soluble and membrane
proteins that are synthesized in the rough ER to the final destination at the cells surface,
this also includes secretion, and going into the lysosomes.It has two stages. ER to Golgi
to Cell Surface to Endosomes to Lysosomes
Endocytic Pathway
· moving inward or taking something up from outside of the cell, ingestion and
degradation of extracellular molecules, can involve a cell taking up a pathogen. Goes
from plasma membrane to endosomes to lysosomes
Golgi
Key player in the biosynthetic secretory and endocytic pathway
Functions of Golgi
receiving transport vesicles from the ER, modifying proteins by glycosylation, and
dispatching secretory proteins in vesicles bound for the extracellular space, PM (plasma
membrane), or lysosome
,Golgi Cis, or forming face
entry face where the proteins from the ER enter the Golgi
Golgi Trans face
exit face, where the proteins leave the Golgi and go into their destined place such as
secretory vesicles, plasma membrane, or lysosomes
How does the Golgi work?
delivers proteins to the cell exterior via vesicles by unregulated secretion, secretory
vesicles whose movement to the plasma membrane/cell exterior can be regulated
(regulated secretion), or endosomes that mature into lysosomes
Coat function
concentrate transport proteins into specialized patches, and mold the forming vesicle
into curved shape
What are the three major coat types?
COPI, COPII, and clathrin coats
The three major types of transport vesicles each have?
different types of protein coat that are formed by a reversible polymerization of a distinct
set of protein coat and subunit
COPII coat
sar1, and goes from ER to cis-Golgi, secretory, and anterograde transport
COPI coat
ARF, cis-Golgi to ER, Golgi to Golgi, Golgi to vesicles (to plasma membrane), Golgi
back to ER by retrograde transport)
Clathrin coats
, ARF, from trans-Golgi to Endosomes/lysosomes by endocytosis
What is vesicle budding initiated by?
I. GTP-binding protein (ARF, Sar) these two different proteins are involved with different
coat proteins
II. Binding of coat protein (clathrin, COP1, COPII)
III. Binding of Cargo (if the cargo membrane is bound) or binding of a cargo-receptor
protein (if the protein is soluble)
IV. Coat proteins shed as vesicle diffuses towards target, exposing v-SNARE
What happens when vesicle fusion occurs?
Newly exposed v-SNARE (vesicle) interact with t-SNARE (target) on target membrane
Interaction allows for docking and fusion of vesicle and target membranes
Early stages of the secretory pathway
Vesicle transport is occurring between the ER and cis-Golgi which is called the initial
transport stage of the secretory pathway. COPII-coated vesicles are transporting newly
synthesized proteins containing Golgi-targeting sequences in their cytosolic domain or
bound to such protein (anterograde/forward direction). ER to Golgi. COPI-coated
vesicles are carrying ER/Golgi-resident proteins in the retrograde/backward direction.
Golgi to ER. They function to retrieve v-SNARE proteins, membranes, and mis-sorted
ER-resident proteins
Later Stages of the Secretory Pathway
This occurs in the trans-Golgi network, and involves a distal sorting compartment that
sorts proteins into five different types of vesicles for transport to the plasma membrane,
endosomes, and lysosomes
