Lecture 5 - Endomembrane System and Bulk Transport Processes Flashcards
What is the endomembrane system?
a membrane system interconnected by direct physical contact or transfer by vesicles.
What organelles make up the endomembrane system?
- nuclear envelope
- endoplasmic reticulum (smooth & rough)
- Golgi apparatus
- vesicles
- lysosomes
- vacuoles
- plasma membrane
Where does synthesis occur in the endomembrane system?
Endoplasmic reticulum
What is responsible for the delivery of proteins?
Vesicles
What “tags and packages” proteins?
The golgi apparatus
What are the functions of the sER?
- Metabolism of carbohydrates
- Lipid synthesis for membranes
- Detoxification of drugs and poisons
- Storage of calcium ions (used as a signal in the cell)
T of F
The amount of sER in a cell is fixed
False
The amount of sER can be increased or decreased to meet demand
What are the functions of the rER?
Protein synthesis
What are the functions of the golgi apparatus?
Receives, modifies, sorts and ships proteins arriving from the rER
T or F
Processed vesicles leave from the
cis face of the Golgi complex
False
Processed vesicles leave at
the trans face while they arrive in the cis face
What is Glycosylation?
Addition (or modification) of
carbohydrates to proteins
T or F
sER stores calcium ions
True
Which one of the following statements concerning the endomembrane system is
INCORRECT?
(A) The Golgi apparatus glycosylates proteins destined for secretion.
(B) Lysosomes contain multiple protein synthesising enzymes.
(C) The rough endoplasmic reticulum is responsible for the synthesis of secretory
proteins.
(D) Exocytosis delivers both proteins and phospholipids to the plasma membrane.
(B) Lysosomes contain multiple protein synthesising enzymes.
Protein synthesis primarily occurs in the rough endoplasmic reticulum (ER) and cytoplasm (free ribosomes).
Which one of the following statements concerning the Golgi complex is INCORRECT?
(A) Proteins passing through the Golgi complex are sorted into specific vesicles.
(B) Vesicles leaving the trans face of the Golgi complex are ʺtaggedʺ for specific
targets.
(C) Endocytosis delivers vesicles directly to the cis face of the Golgi complex.
(D) The Golgi complex glycosylates some proteins destined to be embedded within the plasma membrane.
(C) Endocytosis delivers vesicles directly to the cis face of the Golgi complex.
The process of a cell taking up bulk quantities of specific substances which may be present at only low concentrations in the extracellular fluid is
(A) Receptor-mediated endocytosis (B) Constitutive exocytosis
(C) Phagocytosis
(D) Pinocytosis
(A) Receptor-mediated endocytosis