Flashcards in Cell biology V Deck (41):
Is vesicular transport selective or general?
What is the direction of transport for COP II?
Anterograde - from ER to Golgi
What is the direction of transport for COP I?
Retrograde - from Golgi to ER
What is the purpose of retrograde transport?
To return membrane, v-SNARE, and missorted proteins back to the ER
What are two examples of v-SNAREs?
Synaptotagmin and synaptophysin
What is the purpose of SNARE proteins?
Allow vesicle to recognize its target domain
What effect do the neurotoxins of tetanus and botulism have on SNAREs?
The toxins enter nerve terminals and proteolyse SNARE proteins, preventing vesicles containing neurotransmitters from docking with pre-synaptic membranes of the nerve cell
What effect do tetanus toxins have on neurons?
Enter inhibitory neurons, proteolyse SNAREs, and release brake on the neuron
Are mitochondria acidophilic or basophilic?
Ovoid or threadlike structures - motile and can change shape
What is the diameter of a typical mitochondrion?
0.5 - 1 um
How many mitochondria are there in erythrocytes?
What is the lifespan of a typical mmitochondrion?
How do mitochondria reproduce?
Fission (can also fuse with each other)
Which mitochondrial membrane is selectively permeable?
Inner mitochondrial membrane
Which molecule is responsible for the decreased permeability of the inner mitochondrial membrane?
The cristae of mitochondria are shelf-like in what cell type?
Hepatocytes, cardiac, and muscle cells
The cristae of mitochondria are tubular in what cell type?
Does the morphology of cristae have an effect on mitochondria function?
What cellular processes occur in the mitochondrial matrix?
TCA cycle, fatty acid B-oxidation
Which disease displays "parking lot inclusions" in affected mitochondria?
Myoclonic epilepsy with ragged red fibers (MERRF)
What does catalase do?
Enzymatically forms water and oxygen from hydrogen peroxide
Where does plasmalogen synthesis occur?
Where are peroxisomal enzymes synthesized?
What causes Zellweger syndrome?
Peroxisomal enzymes are not transported into the peroxisome due to defective import protein on the unit membrane of the peroxisome
What happens to peroxisome levels during chronic administration of antilipidemics?
What process in nerve cells is impaired due to defective plasmalogen synthesis?
What are the components of the cytoskeleton?
1) Microtubules2) Microfilaments3) Thick filaments4) Intermediate filaments
What is the diameter of microtubules?
How many longitudinally arranged protofilaments make up a microtubule?
What makes up the protofilaments of microtubules?
Tubulin dimer subunits
What cofactors are required for microtubule synthesis?
1) GTP2) Mg ions
What role does gamma-tubulin have in microtubule synthesis?
Microtubules polymerize from a ring of gamma-tubulin
What drugs inhibit polymerization of microtubules?
1) Colchicine2) Vinblastine3) Vincristine
What drug inhibits depolymerization of microtubules?
What are the functions of microtubules?
1) Structural support of cytoplasm2) Organelle support3) Cell division4) Motility of cilia and flagella5) Long-range transport of vesicles via motor proteins
What is the function of kinesin?
Long-range transport of vesicles toward the periphery
A defect in kinesin has been shown to decrease the transport of receptors for what hormone?
What is the function of dynein?
Long-range transport of vesicles toward the nucleus
What molecule is responsible for long-range transport of vesicles toward the periphery of the cell?