Cell Bio exam II

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  1. *has the small molecule choline attached to a phosphate group as its hydrophilic head
  2. *molecules with both hydrophilic and hydrophobic parts are termed:
  3. Pure phospholipids that will form closed spherical vesicles called:
  4. Whats the two major properties of hydrocarbon tails that affect how tightly they pack in a bilayer?
    Length and # of double bonds
  5. A shorter hydrocarbon chain length will _________  the tendency of the hydrocarbon tails to interact, and _________the fluidity of the bilayer
    • reduce
    • increase
  6. At higher temps the cell makes membrane lipid makes _________ tails that contain ________ double bonds
    • longer
    • fewer
  7. * allows membrane proteins diffuse rapidly
    * allows membrane lipidsand proteins to diffuse
    * ensures that membrane molecules are evenly distributed
    * allows membranes to fuse with one another
    Membrane fluidity
  8. enzymes that catalyze the transfer of lipids from one monolayer to the other
  9. Why is the enzyme scramblases important?
    because new phospholipids are only deposited on the cytosolic half of the bilayer, this enzyme rearranges them so the bilayer is even
  10. How does a membrane with two different monolayers become asymmetrical?
    Golgi has enzymes called flippases, picks specific phospholipids and flips them to the cytosolic layer
  11. monolayer that faces the cytosol
  12. monolayer that faces away from the cytosol
  13. which side of the membrane is glycolipids found?
    noncytosolic half
  14. What happens when enzymes add sugar to the noncytosolic lipid molecule heads?
    glycolipid molecule will remain trapped in this monolayer, nothing can transfer it to the other side
  15. membrane proteins that extend through the bilayer
    transmembrane proteins
  16. membrane proteins that are directly attached to the bilayer either trans, or w/lipid monolayer, or lipid-linked are called
    integral membrane proteins
  17. Membrane Proteins that are not directly attached to the bilayer
    peripheral membrane proteins
  18. the two parts of a transmembrane protein that allow for it to be a part of the bilayer
    hydrophobic side chain bonded with hydrophilic polypeptide backbone
  19. example of a b sheet protein
    porin proteins, form, large, water-filled pore that allow the passage of small nutrients, metabolites, and inorganic ions
  20. why are detergents good at separating bilayers?
    • have only a single hydrophobic tail, shaped like cones, thus aggregate into micelles.
    • interacts and seperates
  21. example of a membrane transport protein that pumps H+ out of the cell
  22. Differences in plant/bacteria vs animal cell walls
    • Plants: proteins, sugars
    • Animals: fibrous proteins call cell cortex
  23. protein in red blood cell that maintains its shape
  24. localized areas within the bilayer where particular proteins are confined
    membrane domains
  25. the surface that faces the gut contents
  26. a barrier formed along the line where the cell is sealed to adjacent epithelial cells
    *membrane proteins cannot diffuse past
    tight junction
  27. proteins that have short chains of sugars linked to them
  28. proteins that contain one or more long polysaccharide chains
  29. sugar coating located on the outside of the plasma membrane that consists of all carbohydrates
  30. membrane proteins that shift small molecules from one side of the membrane to the other by changing shape
  31. membrane proteins that form tiny hydrophilic pores across membranes then a substance can pass through via diffusion
  32. membrane proteins that only permit passage of inorganic ions
    ion channels
  33. molecules that can cross the membrane slowly
    • * inorganic ions
    • * sugars
    • * amino acids
    • * nucleotides
  34. how do hydrophilic molecules cross the membrane
    • simple diffusion
    • facilitated transport
  35. membrane proteins that accelerate transport of hydrophilic molecules
    facilitated transport
  36. molecule order of most to no crossing of the membrane
    • small nonpolar-all
    • uncharged polar-some
    • charged-very little
    • ions-not at all
  37. most import inorganic ions
    • Na+
    • K+
    • Ca2+
    • Cl-
    • H+
  38. electrical imbalances generate a voltage difference across the membrane called:
    membrane potential
  39. exchange of anions and cations across the membrane will be balanced
  40. voltage difference across the cell membrane
    resting membrane potential
  41. the interior of the cell is more _______ charged than the exterior
  42. what does the transport protein transfer?
    molecules or ions that fit into specific binding site on the protein
  43. How does the channel protein discriminate?
    by the size and electrical charge of molecules
  44. When molecules spontaneously flow downhill from higher to lower concentration
    passive transport
  45. movement of a solute against its concentration gradient
    active transport
  46. how is active transport carried out?
    protein transporters called pumps
  47. the two net forces driving a charged solute across a cell membrane
    • concentration gradient
    • membrane potential
    • =electrochemical gradient
  48. concentration gradient + membrane potential=

    * determines the direction that each solute will flow by passive transport
    electrochemical gradient
  49. water moves passively across cell membranes down its concentration gradient
  50. specialized channel proteins for H2O
  51. total concentration of solute particles inside the cell
  52. plant cells osmotic swelling pressure
    turgor pressure
  53. what actively transports a solute against its electrochemical gradient
  54. what moves a solute along its electrochemical gradient?
    passive transporters
  55. 3 types of pumps
    • coupled pump
    • ATP-Driven pump
    • light-driven pump
  56. pump that hydrolyze ATP to drive uphill transport
    ATP-driven pump
  57. pump that link the uphill transport of one solute across a membrane to the downhill transport of another
    Coupled pump
  58. pumps found mainly in bacterial cell, use sunlight energy to drive uphill transport
    Light-driven pump
  59. how does the Na+ pump work?
    uses ATP to expel Na+ and bring in K+

    *coupling, only when appropriate ions are available for transport
  60. How does the Ca+ pump work?
    ATPase, coupling, removing Ca2+ out of cell into the extracellular that has a higher concentration
  61. what does Ca2+ do in the cell?
    • intracellular signal to trigger processes
    • -muscle contraction
  62. when a gradient of any solute across a membrane can be used to drive the active transport of a second molecule
    coupled pumps
  63. coupled pump moves both solutes in the same direction across the membrane
  64. pump that moves only one type of solute across the membrane
  65. coupled pump that moves solutes in opposite directions across the membrane
  66. what kinds of electrochemical gradient pump do animals rely on?
    Na+ pumps and Na+-driven symport
  67. what kind of electrochemical gradient pumps to plants, fungi and bacteria rely on?
    H+ pumps and H+-driven symport
  68. How does the H+ pump work?
    pumps H+ out, creates acid pH in medium surrounding the cell
  69. 2 channels that form relatively large, aqueous pores
    • gap junctions btwn cells
    • porins outer membrane of mitochondria
  70. narrow, highly selective pores/channels
    * facilitate the flow of water across plasma membrane
    * prohibits the movement of ions
  71. * ion selectivity
    * not continusously open-gated
    * does not undergo conformational changes
    * fastest transporter
    ion channels
  72. whats the main inorganic ions that an ion channel transports?
    • Na+
    • K+
    • Ca2+
    • Cl-
  73. these channels randomly flicker open and closed no matter what the conditions are inside or outside the cell, allows free movement
    leak channels
  74. most common leak channel
    K+ leak channel
  75. when the flow of positive and negative ions across the membrane is balanced
    • resting membrane potential
    • * K+ leak channel closed
  76. type of gated channel that is controlled by the membrane potential
    voltage-gated channel
  77. type of gated channel that is controlled by the binding of some molecule to the channel
    ligand-gated channel
  78. type of gated channel that is controlled by a mechanical force applied to the channel
    mechanically-gated channel
  79. when the membrane potential of the plasma membrane shifts to less negative value
  80. what happens when theres a negative membrane potential and the plasma membrane depolarizes?
    voltage-gated Na+ channels open
  81. How does the depolarized axonal membrane return to resting potential?
    voltage-gated K+ channels opening in response to depolarization
  82. channel responsible for the maintenance of resting membrane potential of a plasma membrane
    K+leak channel
  83. channel responsible for generation of action potentials of a nerve cell axon
    Voltage-gated Na+ channel
  84. channel responsible for the return of membrane to resting potential after action potential at the nerve cell axon
    voltage-gated K+ channel
  85. channel responsible for stimulation of neurotransmitter release on plasma membrane of nerve terminal
    voltage-gated Ca2+ channel
  86. channel responsible for excitatory synaptic signaling of the muscle cell
    Acetylcholine receptor/gated cation channel
  87. channel responsible for excite synaptic sign of neurons
    glutamate receptors/gated cation channels
  88. channel responsible for detection of sound vibrations in auditory hair cell
    mechanically=activated cation channel
  89. The ER, Golgi apparatus, peroxisomes, endosomes and lysosomes are all part of what is collectively called:
    Endomembrane system
  90. Possible way membrane bound organelles may have come to be:
    • invagination
    • phagocytosis
  91. where does the synthesis of virtually all proteins begin?
    ribosomes in the cytosol
  92. exceptions  of proteins that are synthesized inside specific organelles instead of in the cytosol
    • mitrochondrial
    • chloroplasts
  93. how is it determined where protein is going to be synthesized?
    amino acid sequence contains sorting signal
  94. 3 ways a protein is transported across membranes
    • nuclear pores
    • protein translocators
    • transport vesicles
  95. enclosure of the nuclear DNA
    nuclear envelope
  96. part of nuclear envelope that contains proteins that act as binding sites for chromosomes and nuclear lamina
    Inner nuclear membrane
  97. finely woven meshwork of protein filaments that line the inner face of membrane and provides structural support for the nuclear envelope
    nuclear lumina
  98. the signal that directs a protein from the cytosol into the nucleus is called:
    nuclear localization signal
  99. the nuclear localization signal on proteins destined for the nucleus is recognized by cytosolic proteins called:
    nuclear import receptors
  100. What protein helps the newly made proteins inside mitochondria and chloroplast and helps refold them again?
    chaperone protein
  101. enzyme that also synthesizes certain phospholipids
  102. THe most extensive membrane system in a eukaryotic cell
  103. What are the two kinds of proteins that are transferred form the cytosol to the ER?
    • Water soluble proteins
    • Prospective transmembrane proteins
  104. translating mRNA with ribosomes binded to it
  105. The two protein components that help guide ER signal sequences to the ER membrane
    • 1. Signal-recognition particle(SRP)
    • 2. SRP receptor
  106. binds to both the ribosome and the ER signal sequence after ribosome
    Signal-recognition particle
  107. embedded in the ER membrane , recognizes the SRP
    SRP receptor
  108. site of detoxification in a cell
    smooth ER
  109. Site of glycosolation
    Golgi Apparatus
  110. type of Golgi that's facing the nucleus
    Cis golgi
  111. type of Golgi that's facing away from the nucleus
    trans golgi
Card Set
Cell Bio exam II
Chap 11, cell membrane, Buff state, BIO 214
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