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77 Cards in this Set

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3 classes of cytoskeleton components
Microfilaments, Intermediate Filaments, and Microtubules
For microtubules and microfilaments, which end polymerizes faster?
plus or beta end for microtubules, barbed end for microfilamentme s
Name two types of intermediate filaments
Lamins in the nuclear envelope, keratins in hair/skin/nails
Which fatty acid is enriched in lipid rafts?
Phosphosphingolipids
Name 2 actin associated proteins
Profalin, Spectrin, gelsolin
RNA is read (translated) in which direction?
5' to 3', that is with longer proteins near the 3' end
What is the difference between post-translational targeting and co-translational targeting?
Post translational targeting occurs in translation in free ribosomes -> nucleus, mitochondria, peroxisome, cytosol. Co-translational targeting is with bound rER ribosomes -> vesicular pathways (golgi/sER to vessicles)
What are some specific functions of the sER?
Syn/Met of FAs and phospholipids, detoxify organic compounds, Syn of steroid hormones in gonads and adrenal cortex, Sarcoplasmic reticulum (Ca storage)
What is COP-II's role in transport?
Coats vessicles at the ER export site for delivery to the golgi
What are the 4 ER subdomains?
rER, sER, nuclear envelope, ER export sites
Describe the morphology of the golgi
Outer convex (cis) face, medial compartment, and trans golgi network. Also, lateral network of cisternae and tubules known as the noncompact zone
Describe the flow of proteins into and out of the golgi
Proteins arrive in COP-II coated vessicles from ER at the cis network. Protein is glycosylated and phosphorylated than budded from trans network. trans cisternae bud into clathrin coated vessicles -> EE, or secretory vessicles. Recyclable rER components and improperly sorted proteins are packaged into COP-I coated vessicles for transport back to ER
What are the four main types of transport vessicles in the cell?
Clathrin coated, COP-I coated, COP-II coated, and secretory vessicles
What is the role of COP-I coated vessicles?
Retrograde transport from TGN to ER for recycling, such as of ER resident proteins
What is the role of SNARE proteins?
targeting transport of vessicles, v-SNAREs pair with t-SNAREs on acceptor compartment to dock incoming vessicles
How does an early endosome mature into a late endosome?
Through exchange of vessicles with the TGN and increasing acidity through action of membrane proton pump
Name 5 cellular junctions in epithelial tissue
Tight junctions (zonula occludens), Zonula adherens, Gap junctions, Desmosomes, Hemidesmosomes,
Which cellular junctions interact w/ intermediate filaments?
Desmosomes and hemidesmosomes
What is the difference between the consitutive pathway and the vessicular secretory pathway?
Constitutive secretions are released continuously, and are not stored as immature vessicles
Name a protein involved in zonula occludens (tight junctions)
Occludin or Claudins
What is catenin's function and where is it found
Found in zonula occludins - peripheral membrane protein joins claudins to actin
What is the most abundant leukocyte in blood?
Neutrophils
Name two lysosomal storage diseases and their dysfunctional protein or pathway
I-cell disease - lysosomal enzymes dont receive M6P. Tay-Sachs disease - GM2 ganglioside buildup
Name the three granulocytes
Eosinophils, Basophils, Neutrophils
What is a caniculus and what is its function?
Small channel in bone through which narrow cytoplasmic processes allow communication between bone cells.
What is plectin's function?
Large globular protein that links MTs, MFs, and IFs
What is katanin?
A microtubule severing protein
Where is vinculin found?
In zonula adherens and focal adhesions - intracellular attachment protein that anchors f-actin
Describe the collagen structures present in the basal lamina
Type IV collagen is prominent in a dense lamina sheet just below the cell, Type VII forms anchoring loops to reticular fibers (Type III collagen). Type XVII collagen is involved in the achoring mechanism of hemidesmosomes
Which cellular junctions interact intracellularly with intermediate fibers?
Desmosomes and hemidesmosomes
What is Whartons Jelly and why has it recently gained attention in medical research?
A mucosal connective tissue found in the umbilical cord containing sparse spindle shaped cells and an ECM rich in GAGs and proteoglycans. Potentially important source of stem cells, as with cord blood
What are the typical physical dimensions of the three classes of cytoskeletal elements?
MFs - 6 nm diameter, IFs - 10 nm diameter, MTs - 25 nm diameter

remember nickel, dime, quarter
What is gamma-tubulin and where is it found?
A tubulin protein that forms rings around the spherical MTOC - site of microtubule nucleation
What are the three types of cartilage?
Hyaline cartilage, elastic cartilage, fibrocartilage
Which collagen is unique to fibrocartilage?
Type I
What is an isogeneous group? What do they imply histologically?
Clumps of dividing cells generally associated with cartilage - implies a site of active mitosis and cartilage growth
What is zellweger's syndrome and what is it's cause?
A disorder of the peroxisomes in which they fail to assemble or function correctly - causes a lethal buildup of long chain fatty acids in the cytoplasm. Caused by mutation in receptor to peroxisome targeting signal.
Where are lamins found? What class of molecule are they?
Theyre an intermediate filament found in the nuclear lamina
What is a transitional epithelium and what is an example of its function in the body
A stratified epithelium in which the apical cells appear large and rounded under relaxed conditions - found in bladder and urinary tract to allow distension
Which leukocyte has a distictive bilobular nucleus?
Eosinophils
What are the two types of adipose tissue
White (unilocular) and brown (multilocular)
What is the role of mast cells?
Release granules rich in histamine, heparin, proteases, etc in response to allergens or pathogens to cause inflammation and recruit leukocytes
From what cells are platelets formed?
Megakaryocytes
What are the two main hormones involved in calcium homeostasis?
PTH raises blood Ca by promoting bone resorption. Calcitonin lowers blood Ca by inhibiting this effect on osteoclasts
Describe the cartilage zones in the direction of bone formation in endochondral bone formation
Zone of calcified cartilage (dead chondrocytes being invaded by bone), Zone of hypertrophy (dying cells, mineralizing cart.), Zone of proliferation (isogeneous groups) Zone of reserve cartilage (normal hyaline cartilage)
What is a basal body?
A peripheral centriole associated with cilia that acts as a MT nucleation site and likely coordinates cilia motion
What is the role of actin filaments in cell motility?
Filaments are polymerized at the leading edge of moving cells, forming lamellipodia that pull the cell along
What is a blood vessel lying orthogonal to lamellae in mature bone called?
Volkman's canal
Which of the major leukocytes is least prevalent under normal conditions?
Basophils
Which of the glycosaminoglycans forms the core of large ECM aggregates?
Hyaluranon
What is leptin?
A hormone released by adipose tissue that acts as feedback for fat stores by lowering appetite
A cartilage bone model is present in which mechanism of bone formation?
Endochondral
What cell type has a characteristic clockface nucleus
Plasma cells - caused by little euchromatin because most of the translational activity in the cell is of only a few antibodies
Name a disease related to intermediate filament mutation
Epidermolysis bullosa simplex - blistering disease caused by keratin mutations
Name a protein involved in actin cross linking
alpha-actinin
What are the three subtypes of striated muscle?
skeletal, visceral striated muscle (soft tissues), cardiac muscle
What stains are used for imaging elastic fibers?
orcein or weigarts
What is kartageners syndrome?
A primary ciliary dyskinesia that causes failure to clear pathogens from the respiratory tract
What are the primary proteins in the contractile apparatus of muscle?
F-actin, troponin, tropomyosin (thin), and myosin II in thick filaments
What is the basic role of tropomyosin and troponin in muscle filaments?
Binds to the myosin II binding site
What is dystrophin?
A protein found in muscle cells thats thought to link actin to extracellular laminin - duchennes muscular dystrophy
What are the five stages of muscle contraction?
attachment, release, bending, force generation, and reattachment
What is osteoid?
unmineralized bone matrix
What is the function of T-tubules in muscle cells?
Allows rapid diffusion of calcium throughout the cell upon depolarization
How does the I-band appear in light microscopy and what structure of the sarcomere causes this appearance?
A light band of thin myofilaments that dont overlap with myosin filaments
What cell type is calmodulin unique to?
Smooth muscle cells
What is the function of dynamin?
Closes newly formed vessicles, as in endocytosis, or in golgi vessicle formation
What endocytotic pathway is preferred by entering pathogens and why?
Caveolae lined vessicles because they dont connect with any pathways leading to lysosomes
What is another name for a tertiary lysosome?
Residual body
Where is M6P added to proteins?
cis-golgi
What endocytotic pathway is preferred by entering pathogens and why?
Caveolae lined vessicles because they dont connect with any pathways leading to lysosomes
What is another name for a tertiary lysosome?
Residual body
Where is M6P added to proteins?
cis-golgi
Acid phosphatase activity is a marker of which organelle?
lysosome
Where is catalase found? What is its function?
in the peroxisome, to break down H2O2
What are the three components of a triad? A diad?
Triad-in skeletal muscle, T tubule and 2 terminal cisternae. Diad - T tubule and 1 terminal cisternae
What effect does calcium have on the the troponin-tropomyosin complex?
Calcium binds to Troponin-C, which releases Troponin-T from its interaction with tropomyosin, moving troponin-I from the myosin binding site on the actin filament