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29 Cards in this Set

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what is the nuclear envelope?
it encloses DNA and defines the nuclear compartment
what does the inner nuclear membrane have?
it contains specific proteins that act as binding sites for the nuclear lamina
what does the outer nuclear membrane have?
it is studded with ribosomes that make proteins transported into perinuclear cisterna

it is continuous with the inner nuclear mbn
what are the nuclear pores composed of?
the nuclear pore complex, which is composed of ~100 diff proteins in octagonal symmetry
what does the nulcear pore complex allow to pass freely?
small, water-soluble molecules
what is the nuclear lamina?
meshwork of intermediate filaments that line the inner nuclear membrane

it is anchored to nuclear pores and the inner nuclear mbn
what is the purpose of the nuclear lamina?
it gives shape and stability to the nuclear envelope

also holds chromatin
what kind of proteins are in the nuclear lamina?
in mammals, lamins (intermediate filaments) in a distinctive square lattice
what happens to the nucleus during mitosis?
nuclear lamina depolymerizes, caused by phosphorylation of nuclear lamins

nuclear envelope broken up into mbn vesicles

dephosphorylation of lamins causes reassembly of lamina
what is the nucleolus?
site of rRNA sytensis and ribosome assembly

consists largely of RNA and proteins;
how does the nucleolus stain on H&E?
basophilic
is the nucleolus membrane bound?
no, not mbn bound

there are no mbn bound organelles within the nucleus
what is the nucleolar organizer region?
DNA from several chromosomes; code for rRNA
what happens to the ribosomal subunits?
synthesized in the nucleolus, leave via nuclear pores, assembled in cytoplasm
how many nucleoli does a cell have?
varies; 2-3 in active cells
what is chromatin?
complex of DNA and proteins
how does chromatin stain?
basophilic
what is heterochromatin and how does it stain?
inactive chromatin

basophilic, and electron dense
what is euchromatin and how does it stain?
active chromatin

lightly staining, electron light
what is the rough endoplasmic reticulum?
organelle with polyribosomes attached to cytosolic surface of mbn

has integral proteins to recognize and bind ribosomes
what is the smooth endoplasmic reticulum?
tubular, and continuous with RER
where is smooth ER found?
cells for lipid synthesis and metabolism

cells for detox of toxic materials
what is the sarcoplasmic reticulum?
specialized smooth ER in striated muscle cells
what does the Golgi apparatus do?
receives proteins from the ER and dispatches then

4-6 curved membranous golgi cisternae
what are the sides of the golgi?
on each stack:
cis face - entry face, curved
trans face - exit face

overall:
cis Golgi network - proteins and lipids enter in transport vesicles (w/ CotII); from ER
trans Golgi network - exit in transport vesicles
how are things transported b/w the cisternae of the golgi?
by coatamer-coated vesicles
how does the golgi stain?
stains poorly;

pale area near nucleus
what is the default method of protein secretion?
constitutive secretory pathway - protein enters RER lumen, then to golgi, then immediately secreted or inserted into cell mbn
what is the regulated secretory pathway?
signal -> protein diverted to organlle or packaged for secretion.