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40 Cards in this Set

  • Front
  • Back
what are the two major types of endocytosis?
pinocytosis and phagocytosis
what characterizes pinocytosis and what it the nickname often given to this process?
characterized by uptake of fluids, macromolecules, and small particles; cell drinking
what characterizes phagocytosis and what it the nickname often given to this process?
characterized by ingestion of large particles (>.5 microns); cell eating
which, phago- or pinocytosis is most heavily reliant on receptor-mediated uptake?
what is the name for the process in which a cell targets its own organelles for degradation by fusion with the endosomal/lysosomal dept?
which of the two methods of endocytosis is most commonly used as a synonym for endocytosis?
what is the name for the molecules that most commonly form the coating in a coated vesicle? are the found on the inside or outside of the cell?
clathrin; inside
after a clathrin pit has been uncoated, what is contained in the vesicle?
membrane, receptors, ligands (target molecules)
are early endosomes characterized by high or low pH? for what early endosomal function does this exceptional pH allow?
low pH; dissociation of receptors and ligands
true or false: when vesicles reach early endosome, membrane is recycled but receptors are not.
false. All recyclable materials are recycled.
in which compartment are ligands broken down by acid hydrolases?
late endosome
in which compartment is terminal digestion of ligands performed?
what is the name for lysosomes filled with undigestible material? what is the name for this material which stains a brownish color?
residual bodies; lipofuscin
how are endosomal and lysosomal compartments normally visualized under a light microscope? why?
via histochemical or immunocytochemical techniques; with a normal stain, the compartments are indistiguishable. their protein makeups distinguish them
what are the two classes of 'professional' phagocytes?
neutrophils and macrophages
what is the name for the process by which the immune system coats invading bacteria with antibodies or complement?
opsonins are engulfed by phagocytes. the resulting body is called what?
a phagosome
true or false. endosomes and lysosomes have identical pH's.
false. The pH of the lysosome is lower than the late endosome which is lower than the early endosome.
which, pinocytosis or phagocytosis, is considered to be a constitutive process?
what proteins, other than clathrin, commonly coats the pits that lead to endocytosis?
the binding of what to the intracellular domain of the receptor triggers the aggregation of clathrin molecules?
adaptin (AP-2)
during endocytosis, what molecule is responsible for making sure the entire vesicle enters the cell (like a purse string)?
what is the term used to describe 3 molecules of clathrin light and heavy chains that form a basket?
at what point is coated vesicle stripped of clathrin coat?
immediately following complete invagination of vesicle.
which is more selective: clathrin or caveoli pits?
what molecule is requires for a coated vesicle to uncoat?
are adaptins unique to each receptor?
no, they can bind to several different receptors
how is the early endosome tranferred to the late endosome?
via microtubule network/motor proteins
among the early and late endosome and lysosome, which have ATPases? what purpose does the ATPase serve in these compartments?
late endosome and lysosome; makes the compartments more acidic.
what is the necessary working environment for acid hydrolases?
acidic environment. will not work in physiological pH
what aspect of lysosomes and late endosomes is crucial in keeping these compartments intact?
because they are clustered near the RER, which confirms their identity as secretory vesicles
in this picture, how would one know that the dark circles are secretory vesicles and not lysosomes?
what happens to actin skeleton when phagocytes want to engulf opsonin?
it reorganizes to accomodate for phagocytosis
what morphological feature do phagocytes use to engulf opsonins?
when a phagosome and a lysosome fuse together, the resulting body is called what?
several phagocytes fused together to accomodate a large opsonin, such as a bacterium or cell
what is a possible explanation for the large, multinucleated cell seen in this stain?
which organelle is responsible for invagination of dead organelles in autophagy?
what is the size limit for pinocytosis?
what is the minimum size for phagocytosis
what is the pH of the early endosome? the late endosome? the lysosome?
6; 5.5-6; 5