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91 Cards in this Set

  • Front
  • Back
what are Mallory bodies?
cell inclusions of keratin protein in cytoplasm of liver cells in cytoplasm of liver cells during alcoholic hepatitis
what organelle provides energy to cells?

most abundant in cardiac muscle cells, liver cells, spermatazoa, and kidney epithelial cells
how do mitochondria replicate?
self-replicating via budding or fission
what are the two unit membranes around mitochondria?
inner mitochondrial membrane (IMM)
outer mitochondrial membrane (OMM)
what are the two physiologically different areas of a mitochondrion?
mitochondrial matrix
intermembrane space
how permeable are the membranes of mitochondria?
outer membrane has relatively large channels (made by porin) permeable to ions and small molecules

inner membrane has lots of cardiolipin which causes it to be relatively impermeable to ions, protons and electrons
what is the structure of the inner mitochondrial membrane?
folded into cristae (shelfs)

lots of cardiolipin
where are the enzymes contained which are involved in electron transport and oxidative phosphorylation?
inner mitochondrial membrane
where are the enzymes contained which are involved in the TCA (Krebs) cycle?
mitochondrial matrix
what is stored in the matrix granules of the mitochondrial matrix?
from what DNA are mitochondrial proteins synthesized?
nuclear DNA

mitochondrial DNA encodes very few proteins, rRNA and tRNA
what are molecular chaperones?
proteins which stabilize unfolded and partially folded proteins, preventing them from being degraded
how are proteins transported into the mitochondria?
signal peptide at the beginning, as well as molecular chaperones (Hsp70) allow the protein to be transported across the membranes
what is Hsp70?
Heat Shock Protein 70

a molecular chaperone which stabilizes unfolded or partially folded proteins as they are transported to the mitochondria
from where do offspring get their mitochondria and mitochondrial DNA?
maternal inheritance

only nuclear DNA is transferred from the sperm upon fertilization
what is the effect of both carbon monoxide poisoning and cyanide poisoning?
blocks oxidative phosphorylation
Leder's Hereditary Optic Neuropathy
mitochondrial myopathy characterized by progressive optic nerve degeneration

caused by mutation in mitochondrial DNA gene for NADH dehydrogenase (complex I)
Myoclonic Epilepsy with Ragged Red Fibers (MERRF)
characterized by general muscle weakness, ataxia, and seizures

caused by point mutation in mitochondrial DNA gene encoding tRNA for lysine (results in altered fcn of several oxidative complexes
what are lysosomes?
membrane bound organelles with over 40 different hydrolytic enzymes

part of cellular digestive system
where is acid phosphatase found almost exclusively?
at what pH are lysosomal enzymes usually most active?
acidic pH (about 5.0)
what are phagosomes?
membrane bound vesicles which contain material destined for lysosomal digestion

(form with primary lysosomes to form secondary lysosomes)
what is the difference between heterophagosomes and autophagosomes?
heterophagosomes contain material of extracellular origin, like bacteria

autophagosomes contain material of intracellular origin, like worn or damaged organelles
from what do residual bodies develop?
secondary lysosomes

(membrane bound vesicles which contain material that can not be digested by lysosomes)
what are lipofuscin granules?
accumulations of undigestible materials in cells (esp. long-lived cells like neurons and cardiac muscle cells)
Tay-Sachs disease
lysosomal storage disease resulting from defect in b-N-acetylhexosaminidase

M2 gangliosides accumulate in brain cells

results in dementia, blindness and death within 3 years of birth
where do lysosomes form?
golgi complex
where do peroxisomes form?
endoplasmic reticulum
where are peroxisomal enzymes synthesized?
synthesized in cytosol on polyribosomes

transported, fully synthesized, into peroxisomes
in which cells are peroxisomes most numerous?
kidney and liver cells
what is the function of peroxisomes?
beta-oxidation of very-long-chain fatty acids into long- or medium-chain fatty acids (not coupled to ATP synthesis)

(after which beta-oxidation continues in the mitochondria)
what is the function of catalase?
peroxisomal enzyme which catalyzes the conversion of peroxide into water and oxygen
what is plasmalogen?
major constituent of myelin in the nervous system
Zellweger syndrome
defect in transport of peroxisomal enzymes into peroxisomes

causes toxic substances to accumulate, affecting kidneys, liver, and brain
X-linked Adrenoleukodystrophy (XALD)
peroxisomal disorder resulting from mutations in genes encoding enzymes necessary for fatty acid beta oxidation

causes abnormal accumulations of lipids in brain and adrenal glands, which trigger inflammatory response and loss of myelin (white matter)
what are peroxisome proliferators (PP)?
drugs, chemicals, and endogenous agents that stimulate proliferation of peroxisomes by binding to PPARs
what are PPARs?
peroxisome proliferator-activated receptors

a group of nuclear receptor proteins that stimulates the proliferation of peroxisomes
what are the staining properties of ribosomes?
intensely basophilic
what are polysomes?
aka polyribosomes

groups or clusters of ribosomes distributed along a single strand of mRNA, which allows multiple copies of a protein to be made from a single RNA simultaneously
what proteins are synthesized by ribosomes associated with the RER?
proteins targeted for...
plasma membrane
what is the endoplasmic reticulum?
a freely anastomosing network of vesicles or cisternae
describe rough endoplasmic reticulum
thin, flattened cisternae studded with ribosomes

basophilic due to ribosomes

abundant in cells specialized for protein secretion
what is the function of RER?
synthesis, packaging, and processing of proteins
what is the function of ribophorin?
mediate attachment of signal sequence and large ribosome subunit to RER membrane

provide channel for passage of developing protein into RER lumen
what are the functions of the two subunits of ribosomes?
small - binding sites for mRNA and tRNA

large - enzymatic activity (peptidyl transferase) that attaches amino acids
what modifications of proteins are performed in the RER?
folding of proteins into 3D structure
association of protein subunits
N-linked glycosylation
hydroxylation (collagen)
what is N-linked glycosylation?
addition of sugars to asparagine residues

(begins in RER and finishes in golgi complex)
describe smooth endoplasmic reticulum
appears smooth in electron micrographs

wider and more tubular cisternae than RER

stains poorly (usually not visible with light microscope)
what are the functions of SER?
synthesis of membrane lipids

synthesis of steroid hormones

detoxification by cytochrome P-450 enzymes

sequestering calcium ions
what can inhibit P-450?
grapefruit juice
what is the function of the P-450 system?
detoxifies drugs and toxic compounds

breaks down normal metabolic products like bilirubin and sex hormones
what is sarcoplasmic reticulum?
specialized form of SER present in skeletal and cardiac muscle cells which serves as a reservoir for calcium ions
where are golgi complexes typically found?
near the nucleus
near the centrioles
what is the difference between the cis- and trans- faces of the golgi apparatus?
cis-face (forming face) is the convex outer surface (towards ER)

trans-face (maturing face) is the concave inner surface (away from ER)
what are the functions of the golgi complex?
packaging of secretory products
polysaccharide synthesis
modification of secretory products
concentration of secretory products
membrane synthesis and recycling
what are COP-coated or coatomer vesicles?
vesicles covered with coat protein (COP) which transport materials between stacks of the golgi apparatus, and from RER to golgi apparatus
what is the difference between COP-I and COP-II?
COP-I guides retrograde transport between rER and cis-face of golgi apparatus (from golgi to RER)

COP-II guides anterograde transport between rER and cis-face of golgi apparatus (from RER to golgi)
what are SNAREs?
transmembrane proteins in transfer or secretory vesicles which allow them to fuse to the target membrane
what are the proteinacous, filamentous elements of the cytoskeleton?
intermediate filaments
what is the thickest cytoskeletal component?

where are they found?
microtubules (24 nm)

found throughout cytoplasm
of what are microtubules composed?
polymerized heterodimers of alpha-tubulin and beta-tubulin
how many protofilaments make up a microtubule?

(protofilaments are the columns of tubulin dimers, stacked alpha-tubulin to beta-tubulin)
what is required for tubulins to assemble?

alpha- and beta-tubulin are GTPases
where does assembly and disassembly of microtubules take place?
assembly - (+) end - away from nucleus

disassembly - (-) end - close to nucleus
what are kinesin and dynein?
microtubule-associated ATPase proteins which carry enzyme-transport vesicles, organelles and metaphase chromosomes

kinesin - anterograde - from (-) to (+)
dynein - retrograde - from (+) to (-)
what are the functions of microtubules?
maintain cell shape

movement of chromosomes during mitosis

movement of secretory granules, neurosecretory vesicles and organelles

beating of cilia and flagella
what is used to arrest chromosomes in metaphase for karyotyping?

anti-mitotic alkaloid
what are the thinnest cytoskeletal elements?
microfilaments (5-7 nm)
of what are microfilaments composed?
Globular (G)-actin monomers polymerizing to form helical, filamentous (F)-actin
where do microfilaments polymerize and depolymerize?
polymerize - (+) end

depolymerize - (-) end
what is thymosin?
proteins which bind G-actin and inhibit its assembly into microfilaments
what is profillin?
protein which binds and sequesters G-actin, but also promotes assembly of F-actin
what cytoskeletal structure is abundant in microvilli and pseudopodia?
(actin filaments)
in what processes are actin microfilaments involved?

cell motility

movement of organelles and vesicles

equatorial constriction during telophase
what cytoskeletal elements are intermediate in thickness?
intermediate filaments (10-12 nm)
what are the most stable cytoskeletal elements?
intermediate filaments
by what are intermediate filament monomers regulated?
in what cells is cytokeratin an intermediate filament?
epithelial cells
in what cells is vimentin an intermediate filament?
endothelial cells
vascular smooth muscle

(mesenchymal origin)
in what cells is desmin an intermediate filament?
skeletal muscle
nonvascular smooth muscle
in what cells is neurofilament an intermediate filament?
in what cells is glial fibrillar acidic protein (GFAP) an intermediate filament?
Schwann cells
ependymal cells
in what cells are lamins A, B, and C intermediate filaments?
all cells, in the inner membrane of the nuclear envelope
of what do centrioles consist?
9 microtubule triplets in a circular array
where are centrioles?
a pair near the center of each cell, oriented perpendicular to one another
what is a centrosome?
microtubule organizing center (MTOC) during interphase

consists of a pair of centrioles plus pericentriolar material
which end of the microtubule is adjacent to the MTOC during interphase?
(-) end of the microtubule is adjacent to the MTOC
where are cilia most numerous?
respiratory passages
of what is the core (axoneme) of cilia composed?
9 microtubule doublets surrounding 2 unjoined microtubules
what anchors and organizes the axoneme of a cilia?
basal body

(9 microtubule triplets at the base of each cilium or flagellum)
Kartagener's syndrome
aka immotile cilia syndrome

defect in ciliary and flagellar motility associated with absent or irregular dynein arms

causes respiratory problems and male sterility