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91 Cards in this Set
- Front
- Back
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what are Mallory bodies?
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cell inclusions of keratin protein in cytoplasm of liver cells in cytoplasm of liver cells during alcoholic hepatitis
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what organelle provides energy to cells?
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mitochondria
most abundant in cardiac muscle cells, liver cells, spermatazoa, and kidney epithelial cells |
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how do mitochondria replicate?
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self-replicating via budding or fission
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what are the two unit membranes around mitochondria?
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inner mitochondrial membrane (IMM)
outer mitochondrial membrane (OMM) |
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what are the two physiologically different areas of a mitochondrion?
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mitochondrial matrix
intermembrane space |
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how permeable are the membranes of mitochondria?
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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 |
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what is the structure of the inner mitochondrial membrane?
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folded into cristae (shelfs)
lots of cardiolipin |
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where are the enzymes contained which are involved in electron transport and oxidative phosphorylation?
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inner mitochondrial membrane
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where are the enzymes contained which are involved in the TCA (Krebs) cycle?
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mitochondrial matrix
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what is stored in the matrix granules of the mitochondrial matrix?
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calcium
magnesium |
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from what DNA are mitochondrial proteins synthesized?
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nuclear DNA
mitochondrial DNA encodes very few proteins, rRNA and tRNA |
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what are molecular chaperones?
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proteins which stabilize unfolded and partially folded proteins, preventing them from being degraded
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how are proteins transported into the mitochondria?
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signal peptide at the beginning, as well as molecular chaperones (Hsp70) allow the protein to be transported across the membranes
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what is Hsp70?
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Heat Shock Protein 70
a molecular chaperone which stabilizes unfolded or partially folded proteins as they are transported to the mitochondria |
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from where do offspring get their mitochondria and mitochondrial DNA?
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maternal inheritance
only nuclear DNA is transferred from the sperm upon fertilization |
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what is the effect of both carbon monoxide poisoning and cyanide poisoning?
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blocks oxidative phosphorylation
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Leder's Hereditary Optic Neuropathy
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mitochondrial myopathy characterized by progressive optic nerve degeneration
caused by mutation in mitochondrial DNA gene for NADH dehydrogenase (complex I) |
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Myoclonic Epilepsy with Ragged Red Fibers (MERRF)
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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 |
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what are lysosomes?
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membrane bound organelles with over 40 different hydrolytic enzymes
part of cellular digestive system |
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where is acid phosphatase found almost exclusively?
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lysosomes
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at what pH are lysosomal enzymes usually most active?
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acidic pH (about 5.0)
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what are phagosomes?
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membrane bound vesicles which contain material destined for lysosomal digestion
(form with primary lysosomes to form secondary lysosomes) |
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what is the difference between heterophagosomes and autophagosomes?
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heterophagosomes contain material of extracellular origin, like bacteria
autophagosomes contain material of intracellular origin, like worn or damaged organelles |
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from what do residual bodies develop?
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secondary lysosomes
(membrane bound vesicles which contain material that can not be digested by lysosomes) |
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what are lipofuscin granules?
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accumulations of undigestible materials in cells (esp. long-lived cells like neurons and cardiac muscle cells)
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Tay-Sachs disease
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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 |
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where do lysosomes form?
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golgi complex
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where do peroxisomes form?
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endoplasmic reticulum
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where are peroxisomal enzymes synthesized?
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synthesized in cytosol on polyribosomes
transported, fully synthesized, into peroxisomes |
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in which cells are peroxisomes most numerous?
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kidney and liver cells
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what is the function of peroxisomes?
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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) |
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what is the function of catalase?
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peroxisomal enzyme which catalyzes the conversion of peroxide into water and oxygen
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what is plasmalogen?
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major constituent of myelin in the nervous system
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Zellweger syndrome
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defect in transport of peroxisomal enzymes into peroxisomes
causes toxic substances to accumulate, affecting kidneys, liver, and brain |
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X-linked Adrenoleukodystrophy (XALD)
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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) |
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what are peroxisome proliferators (PP)?
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drugs, chemicals, and endogenous agents that stimulate proliferation of peroxisomes by binding to PPARs
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what are PPARs?
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peroxisome proliferator-activated receptors
a group of nuclear receptor proteins that stimulates the proliferation of peroxisomes |
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what are the staining properties of ribosomes?
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intensely basophilic
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what are polysomes?
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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 |
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what proteins are synthesized by ribosomes associated with the RER?
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proteins targeted for...
secretion plasma membrane lysosomes |
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what is the endoplasmic reticulum?
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a freely anastomosing network of vesicles or cisternae
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describe rough endoplasmic reticulum
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thin, flattened cisternae studded with ribosomes
basophilic due to ribosomes abundant in cells specialized for protein secretion |
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what is the function of RER?
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synthesis, packaging, and processing of proteins
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what is the function of ribophorin?
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mediate attachment of signal sequence and large ribosome subunit to RER membrane
provide channel for passage of developing protein into RER lumen |
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what are the functions of the two subunits of ribosomes?
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small - binding sites for mRNA and tRNA
large - enzymatic activity (peptidyl transferase) that attaches amino acids |
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what modifications of proteins are performed in the RER?
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folding of proteins into 3D structure
association of protein subunits N-linked glycosylation hydroxylation (collagen) |
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what is N-linked glycosylation?
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addition of sugars to asparagine residues
(begins in RER and finishes in golgi complex) |
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describe smooth endoplasmic reticulum
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appears smooth in electron micrographs
wider and more tubular cisternae than RER stains poorly (usually not visible with light microscope) |
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what are the functions of SER?
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synthesis of membrane lipids
synthesis of steroid hormones detoxification by cytochrome P-450 enzymes sequestering calcium ions |
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what can inhibit P-450?
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grapefruit juice
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what is the function of the P-450 system?
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detoxifies drugs and toxic compounds
breaks down normal metabolic products like bilirubin and sex hormones |
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what is sarcoplasmic reticulum?
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specialized form of SER present in skeletal and cardiac muscle cells which serves as a reservoir for calcium ions
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where are golgi complexes typically found?
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near the nucleus
near the centrioles |
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what is the difference between the cis- and trans- faces of the golgi apparatus?
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cis-face (forming face) is the convex outer surface (towards ER)
trans-face (maturing face) is the concave inner surface (away from ER) |
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what are the functions of the golgi complex?
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packaging of secretory products
polysaccharide synthesis modification of secretory products concentration of secretory products membrane synthesis and recycling |
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what are COP-coated or coatomer vesicles?
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vesicles covered with coat protein (COP) which transport materials between stacks of the golgi apparatus, and from RER to golgi apparatus
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what is the difference between COP-I and COP-II?
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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) |
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what are SNAREs?
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transmembrane proteins in transfer or secretory vesicles which allow them to fuse to the target membrane
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what are the proteinacous, filamentous elements of the cytoskeleton?
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microtubules
microfilaments intermediate filaments |
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what is the thickest cytoskeletal component?
where are they found? |
microtubules (24 nm)
found throughout cytoplasm |
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of what are microtubules composed?
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polymerized heterodimers of alpha-tubulin and beta-tubulin
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how many protofilaments make up a microtubule?
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13
(protofilaments are the columns of tubulin dimers, stacked alpha-tubulin to beta-tubulin) |
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what is required for tubulins to assemble?
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GTP
alpha- and beta-tubulin are GTPases |
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where does assembly and disassembly of microtubules take place?
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assembly - (+) end - away from nucleus
disassembly - (-) end - close to nucleus |
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what are kinesin and dynein?
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microtubule-associated ATPase proteins which carry enzyme-transport vesicles, organelles and metaphase chromosomes
kinesin - anterograde - from (-) to (+) dynein - retrograde - from (+) to (-) |
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what are the functions of microtubules?
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maintain cell shape
movement of chromosomes during mitosis movement of secretory granules, neurosecretory vesicles and organelles beating of cilia and flagella |
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what is used to arrest chromosomes in metaphase for karyotyping?
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colchicine
anti-mitotic alkaloid |
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what are the thinnest cytoskeletal elements?
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microfilaments (5-7 nm)
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of what are microfilaments composed?
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Globular (G)-actin monomers polymerizing to form helical, filamentous (F)-actin
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where do microfilaments polymerize and depolymerize?
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polymerize - (+) end
depolymerize - (-) end |
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what is thymosin?
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proteins which bind G-actin and inhibit its assembly into microfilaments
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what is profillin?
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protein which binds and sequesters G-actin, but also promotes assembly of F-actin
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what cytoskeletal structure is abundant in microvilli and pseudopodia?
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microfilaments
(actin filaments) |
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in what processes are actin microfilaments involved?
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phagocytosis
cell motility movement of organelles and vesicles equatorial constriction during telophase |
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what cytoskeletal elements are intermediate in thickness?
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intermediate filaments (10-12 nm)
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what are the most stable cytoskeletal elements?
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intermediate filaments
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by what are intermediate filament monomers regulated?
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phosphorylation
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in what cells is cytokeratin an intermediate filament?
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epithelial cells
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in what cells is vimentin an intermediate filament?
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endothelial cells
vascular smooth muscle fibroblasts chondroblasts macrophages (mesenchymal origin) |
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in what cells is desmin an intermediate filament?
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skeletal muscle
nonvascular smooth muscle |
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in what cells is neurofilament an intermediate filament?
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neurons
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in what cells is glial fibrillar acidic protein (GFAP) an intermediate filament?
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astrocytes
oligodendroglia microglia Schwann cells ependymal cells pituicytes |
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in what cells are lamins A, B, and C intermediate filaments?
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all cells, in the inner membrane of the nuclear envelope
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of what do centrioles consist?
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9 microtubule triplets in a circular array
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where are centrioles?
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a pair near the center of each cell, oriented perpendicular to one another
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what is a centrosome?
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microtubule organizing center (MTOC) during interphase
consists of a pair of centrioles plus pericentriolar material |
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which end of the microtubule is adjacent to the MTOC during interphase?
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(-) end of the microtubule is adjacent to the MTOC
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where are cilia most numerous?
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respiratory passages
oviduct |
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of what is the core (axoneme) of cilia composed?
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9 microtubule doublets surrounding 2 unjoined microtubules
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what anchors and organizes the axoneme of a cilia?
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basal body
(9 microtubule triplets at the base of each cilium or flagellum) |
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Kartagener's syndrome
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aka immotile cilia syndrome
defect in ciliary and flagellar motility associated with absent or irregular dynein arms causes respiratory problems and male sterility |
