lecture 9 ( Intracellular Compartments and Protein Transport) Flashcards
which types of protein needs to enter through the ER first?
1) golgi apparatus protein
2) endosomes
3) lysosomes
4) to the surface of the cell
5) outside the cell
The 2 types of protein transferred to the ER:
- water soluble protein (crosses the membrane completely)
- prospective transmembrane protein (embedded)
what is the ER signal sequence?
its a segment of 8 or more hydrophobic amino acid
what affect does the SRP binding to ribosome carrying the protein have on protein synthesis?
it slows the protein synthesis until the SRP receptor engages
what is the two types of polyribosomes?
- polyribosomes free in cytosol (free ribosomes)
- polyribosomes bound to ER (membrane bound ribosome)
what causes the transmembrane protein to be embedded in the ER membrane?
the hydrophobic stop signal sequence remins uncleaved therefore the protein is embedded.
what removes the start transfer sequnce after protein is synthesized in the ER?
signal peptidase
what is the 2 functions for the ER signal sequnce ?
1) directing protein to the ER
2) opens the gate of the channel of the translocator
There are two types of Transmembrane Protein:
1) Single Pass Transmembrane Protein
2) Multi Pass Transmembrane Protein
What is the function of the SRP receptor?
releases the SRP and passes the protein to the Translocator.
what causes the transmembrane protein to be thredded across the ER membrane?
the multiple start and stop hydrophobic signles allows the continuation of protein synthesis without drafting away from the lipid bilayer and without removing the start signle sequnce.
True or False: the free polyribosomes is the ribosomes on the Rough Endoplasmic Reticulum.
False, the membrane bound polyribosomes
The movement of secretory pathway:
ER -> Golgi appartus -> Cell surface
The movement of Endocytic Pathway:
molecules from the plasma membrane -> endosomes -> lysosmes
what is the endocytic pathway responsible for?
responsible for the degradation of extracellular molecules
what is the endocytic pathway responsible for?
responsible for the degradation of extracellular molecules
What are Coated Vesicles?
vesicles that bud from membrans of distinctive protein surface
True or False:The best way to study vesicles is by clatherin vesicles
True
Clatherin Coated Vesicles
vesicles that transport proteins from the golgi to the outside and from the plasma membrane to the inside
Dyamin is:
an intercellular protein shaped as a ring around the neck of the coated pit and pinches the vesicle away from the orgin membrane
what is the protein coat for golgi clathrin vesicles?
clathrin + adaptin 1
what is the protein coat for plasma membrane clathrin vesicles?
clathrin + adaptin 2
how does vesicles select cargo?
through the adaptin by trapping the receptor carrying that signal
How does the targeted membrane identifies vesicles?
by tethering protein which recongnizes Rab protein (on the vesicle) on the surface of the memebrane
True or False: The identification process depends on a diverse family of monomeric
GTPases called Rab proteins.
True
True or False: Each organelle and each type of transport vesicle carries the same combination of Rab proteins
False, different combination which acts as a marker for each membrane type.
What are SNARE’s
it’s an additional recognition protein (transmembrane protein). v-SNARE is the protein on the vesicle which firmly attaches to the t-SNARE which is the protein on the targeted membrane to firmly adjust the vesicle for fusion.
What is the type of COP protein originated from the 1) ER 2) Golgi cisterna 3) Golgi apparatus?
1) COP 2
2) COP 1
3) COP 1
