Cell & Molec 2

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Cell & Molec 2
2011-11-08 18:39:45
Cell Molec

Cell & Molec Exam 2
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  1. The three main membrane lipids are....
    • Phospholipids
    • Glycolipids
    • Sterols
  2. The fluidity of the membrane is increased by what two things?
    • unsaturated fatty acids in phospholipids
    • sterols
  3. The three main membrane proteins are:
    • Peripheral
    • Integral
    • Lipid Anchored
  4. These membrane proteins are bound to the outer face of the membrane, or weakly bound to the proteins inside the membrane. Can be removed from the membrane with salts, pH change, etc.
  5. These membrane proteins have tranmembrane alpha-helices and the amino acids in them have hydrophobic side-chains. Can only be removed from membranes with detergents.
  6. This membrane protein has a covalently attached lipid molecule which inserts into the membrane.
    Lipid anchored
  7. What does SDS-PAGE stand for?
    Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (of proteins).
  8. Diffusion is the movement of molecules from ____ to ____ concentration.
    High to Low
  9. Diffusion is Endergonic or Exergonic in nature?
  10. Simple diffusion (unaided movement) is limited mainly to what 6 molecules?
    • H2O
    • O2
    • CO2
    • NO
    • NH3
    • Urea
  11. Facilitated diffusion is movement of a molecule across the membrane from high to low assisted by a ______.
    carrier protein
  12. If you were to plot simple diffusion as the rate of solute transport vs solute concentration the resulting graph would be:
  13. If you were to plot facilitated diffusion as the rate of solute transport vs solute concentration, the resulting graph would show:
    solute transport reaching a maximum rate (vmax) at high solute concentrations.
  14. Unlike active transport, facilitated diffusion...
    • Can't carry a molecule against it's concentration gradient
    • Could function even if ATP synthesis were inhibited
  15. Name two facilited diffusion proteins.
    • Channel Proteins
    • Carrier Proteins
  16. These facilited diffusion proteins are like protein tubes thru the membrane. They are gated, meaning they are closed except if stimulated by mechanical movement, charge depolarization, or ligand binding.
    Channel Proteins
  17. These facilitated diffusion proteins bind molecules, change conformation and release the molecule on the other side of the membrane. They can carry one kind of molecule (uniport) or two (cotransport).
    Carrier Proteins
  18. The kind of cotransport where both molecules move in the same direction is called:
  19. The kind of cotransport where both moelcules move in opposite directions is called:
  20. Active transport moves molecules from ____ to ___ concentration and requires energy.
    Low to High
  21. In Direct Active Transport, energy is supplied by ______.
    ATP Hydrolysis
  22. What are the four different types of Direct Active Transport?
    • F-type ATPase pumps
    • P-type
    • V-type
    • ABD Transporters
  23. This kind of Direct Active Trasport transports protons in bacteria, mitochondria, and chloroplasts. Often function in reverse ATp synthase.
    F-type ATPase Pumps
  24. This kind of Direct Active Transport involves on polypeptide, reversibly phosphorylated by ATP, and inhibited by vanadate.
  25. This kind of Direct Active Transport is often found in vesicles. It is not phosphorlated and not vanadate sensitive.
  26. This kind of Direct Active Transport stands for ATP Binding Casette and is used to transport large solutes, sugars and amino acids.
    ABC Transporters
  27. This kind of transport doesn't hydrolyze ATP directly, but relies on a concentration gradient of some ion (often Na+ or H+) to transport another molecule.
    Indirect Active Transport
  28. What three things does the Extracellular Matrix (ECM) in the connective tissue of animal cells consist of?
    • Adhesive Proteins
    • Polysaccarhide-Protein Complexes
    • Fibrous Structure Proteins
  29. Name two types of Structural Proteins of ECM.
    • Collagens
    • Elastins
  30. These ECM Structural Proteins are rich in glycine, hydroxylysine, and hydroxyproline and form a rod-like helix of 3 polypeptides. It is secreted by fibroblasts into the ECM, and is assembled into staggered rows of fibrils (which are then assembled into fibers). Often found in cartilage and other connective tissues where tensile strength is needed.
  31. These ECM Structural Proteins are rich in Glycine and Proline. The polypeptides are cross-linked at lysine residues. Very Elastic. May be lost in aging.
  32. There is only one polysaccharides of the extracellular matrix (ECM) and that is...
    Glycosaminoglycans (GAGs)
  33. This ECM polysacharide are modified polysaccharide chains. They bind much water and cations, forming a squishy, gelatinour matrix. They are covalently bound to core proteins to form proteoglycans, which are bound to the outer surface of cells by adhesive proteins like integrins.
    Glycosaminoglycans (GAGs)
  34. Name two Adhesive Glycoproteins
    • Fibronectins
    • Laminins
  35. These adhesive glycoproteins are common in the ECM and are secreted by many cells. They are large (270 kDa), with two smaller subunits. Important in cell attachment to surfaces, determining cell shape, cell migration and embryonic development and blood clotting.
  36. These adhesive glycoproteins are found in the basal lamina (a layer of connective tissue beneath epithelial cells surrounding interior of blood vessels and gut) and also around muscle cells. About 850 kDa. They have binding sites for cell surface receptors and collagen. They can bind to themselves, type IV collagen, and entactin to form a fibrous network, and can act like a filter.
  37. These kinds of glycoproteins include integrins like the fibronectin receptor. Outer domains binds fibronectin, transmembrane helices. The Cytoplasmic domain binds Talin. Talin liks receptor to actin microfilaments of the cytoskeleton.
    Receptor Glycoproteins
  38. ________ (require Ca2+) and _______ (Ca2+ independent) are glycoproteins bound to the plasma membrane, and extend outside the cell. Antibodies against either one of these disrupt the binding of cells to each other. Removal of Ca2+ from media can also prevent cell-cell binding mediated by that which requires it.
    • Cadherins
    • N-CAMS
  39. Polysaccharide groups attached to the cell surface have a role in cell recognition, because ______ secreted into the ECM bind certain polysaccharides, attaching cells together.
  40. These anchor cells tightly to each other, or to the basal lamina.
    Adhesive Junctions
  41. These join plasma membrane of adjacent cells.
  42. ______ of intracellular attachment proteins are inside the membrane, ______ stick out to other cell. _____ join plaque to cytoskeleton.
    • Plaques
    • caherins
    • Tonofilaments
  43. This is like half desmosome, joins cell to basal lamina.
  44. These are ridges between adjoining epithelial cells which prevent diffusion of most solutes across epithelial cells by eliminating intracellular space. Also keep membrane proteins localized at one end of the epithelial cell.
    Tight Junctions
  45. These are formed by connexon proteins, tubes allowing free diffusion of molecules < 1200 kDa from cell to cell.
    Gap Junctions
  46. These cells are surrounded by a cell wall composes for layers of cellulose microfibrils and other components like pectin.
    Plant Cells
  47. The cytoplasm of adjacent plant cells may be connected by:
  48. ______ may use cell surface proteins of mammals as binding sites during infection.
  49. This is a system of membrane-bound sacs or tubes, lumen continuous with perinuclear space.
    Endoplasmic Reticulum (ER)
  50. When seperated from broken cells by ultracentrifugation, the ER forms closed, rounded vesicles called ____.
  51. Soluble cytoplasmic proteins are made in _____.
    free ribosomes in cytoplasm
  52. These are synthesized in the ribosomes of rough ER, processed - disulfide bridges made, carbohydrate groups attached. Then secreted proteins may be processed further in golgi complex.
    Soluble secreted or membrane-bound proteins
  53. This is the formation of most membrane phospholipids. It has flippases to translocate phospholipids from one membrane monolayer into other.
    Lipid Synthesis
  54. What are the three main roles of Smooth ER?
    • Detoxification of Xenobiotic (foreign, harmful) compounds
    • Carbohydrate Catabolism
    • Calcium Storage
  55. This is a small, membrane-bound cytochrome with b-heme, activates O2 to oxidize difficult substances: Fatty Acids, Drugs, Toxins, Etc.
    Cytochrome P450
  56. Describe the process of Carbohydrate Catabolism in 5 steps and the result.
    • Glycogen stored in granules outside smooth ER in liver cells.
    • Epinephrine - receptor-G-protein-adenyly cyclase-cAMP triggers glycogen phosphorylase
    • Glycogen breakdown to glucose 1-P
    • Converted to glucose 6-P by phosphoglucomutase
    • Glucose 6-P converted to glucose 6-phosphate.
    • Result: Can then export to other cells.
  57. Active transport pumps in smooth ER, membrane causes Ca2+ to accumulate. Channel proteins can release the Ca2+ from ER into the cytosol by which two ways?
    • Inositol triphosphate binding
    • Binding of neurotransmitter in meuromuscular juction (leads to muscle contraction)
  58. This is the site if synthesis and initial processing of secreted and membrane proteins. Closely related to Golgi Complex, stack of flattended sacs.
    Rough ER
  59. These bud off the rough ER and fuse to cis-face of Golgi.
    Transition Vesicles
  60. These bud off the trans-face of Golgi.
    Secretory vesicles
  61. This may be constitutive of regulated (ex release of digestive enzymes from pancreas).
  62. This is an uptake of materials from outside the cell by infolding plasma membrane.
  63. Large particles ingested (receptors may be involved in leucocytes).
  64. Ingestion of solutions of molecules by in-pocketing of membrane.
  65. This is where a ligand binds to membrane receptors, forms clathrin coated pit, with adaptor protein and dynein, which causes vesicle to bud off. Vesicle loses coat, fuses with early endosome, then can fuse with lysosome for digestion. Involved in binding of Epidermal Growth Factor, uptake of low-density lipoproteins containing cholesteral.
    Receptor Mediated Endocytosis
  66. This consists of 3 heavy and 2 light chains, forms triskelions, and assemble into hexagonal network around vesicles.
  67. These contain oxidases which oxidize difficult substances, like long-chain fatty acids, forming toxic hydrogen peroxide. In plant leaves these reclaim glycolate resulting from photorespiration, eventually converting it back to 3-P glycerate.
  68. A low value of Kd indicates ____ binding.
  69. Receptors can be downregulated by __________ (endocytosis) or by modification of the receptor.
    physical removal
  70. What are the three main kinds of receptors on plasma membranes?
    • G-protein linked
    • Tryosine Kinase
    • Serine/Threonine Kinase
  71. For this kind of receptor, ligand binds on the extracellular domain of the receptor, while there is a long C-term region in the cytoplasm which binds a G-protein.
    G-protein linked receptors
  72. G-proteins are named because they bind and hydrolyse ____, which regulates their activity.
  73. G-protein a-GTP may activate ____ _____, which converts ATp to cAMP.
    Adenylyl Cyclase
  74. cAMP can activate _________, which phosphorylates many enzymes, regulating their activity.
    Protein Kinase A
  75. A __________ removes cAMP by converting it to AMP.
    cyclic phosphodiesterase
  76. Exocrine hormones Epinephrine and Norepinephrine secreted into blood by adrenal glad ("fight or flight response") is an example of a...
    G-protein mediated signal pathway.
  77. This targets epithelial cells.
    Epidermal Growth Factor
  78. This targets mesenchyme, fibroblasts.
    Fibroblast Growth Factor
  79. This regulates cell development.
    Transforming Growth Factor
  80. What are the two ways a cell can die?
    • Necrosis
    • Apoptosis
  81. This is cell death following massive injury to tissue, rupture of cells, leading to extensive inflamation.
  82. This is a death pathway program, where chromatin condenses, DNA cut into up, cytoplasm shrinks, cell fragments to "apoptotic bodies" by blebbing, consumed by macrophages.
  83. Cytoskeleton is a network of protein filaments of 3 types:
    • Microtubules
    • Microfilaments
    • Intermediate Filaments
  84. The two types of microtubules are:
    • Axonemal
    • Cytoplasmic
  85. These microtubules are highly ordered, stable, and found in cilia and flagella.
  86. These microtubules are less ordered, more dynamic, and found in nearly all eukaryotic cells.
  87. Two main kinds of motility systems in eukaryotes are...
    • Microtubules based movement
    • Microfilament based movement
  88. This kind of movement moves vesicles or organelles like lysosomes.
    Microtubule based movement
  89. In microtubule based movement, the ____ ends of microtubules are located at the centriole (near Golgi complex) and the ____ ends are orientated away from the Golgi.
    • minus
    • plus
  90. Consist of 2 heavy chains, 2 light chains. A stalk
    attaches to the vesicle or organelle, one of 2 feet bind to MT. As ATP is hydrolyzed, the feet alternately detach or bind the MT, pulling the organelle or vesicle towards (+) end of MT.
  91. Cytoplasmic or Axonemal (found in cilia or flagella)
  92. ____ carries vesicles from ER and plasmas
    membrane to the Golgi complex, ____ away from the Golgi.
    • Dynein
    • kinesin
  93. movement of cilia and flagella
    Axonemal Dynein
  94. Cadherins are dependant on ____ to function.