Exam 3 Flashcards

1
Q

Lipids are what?

A

Amphiphilic (hydrophilic and hyrdrophobic)

Make up 50% of membranes

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2
Q

What are the major lipids?

A

Phosphoglycerides, sphingolipids, and sterols

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3
Q

Sphingomyelin is derived from?

A

Sphingosine

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4
Q

The four phospholipids except sphingomyelin are derived from?

A

Glycerol

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5
Q

Cholesterol is?

A

A rigid planar sterol

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6
Q

Hydrophilic groups can?

A

Hydrogen bond with water but hydrophobic groups cannot

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7
Q

Amphiphilic molecules will spontaneously?

A

Form micelles or lipid bilayers in water

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8
Q

Caveolae are?

A

A lipid raft that does endocytosis

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9
Q

Lipid rafts are found in?

A

The lipid bilayer/membrane

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10
Q

Lipid droplets are what?

A

Organelles that store fatty acids in a monolayer of phospholipid

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11
Q

Glycolipids are assembled where?

Where are they found?

A

Assembled in the Golgi and delivered to membrane

Found on the non-cytosolic surface of lipid bilayers(membranes)

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12
Q

Membrane proteins anchor to a membrane through?

A

Either a fatty acid chain or a prenyl group attaching through amide linkage or thioester linkage to cysteine

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13
Q

Transmembrane domains contain?

A

Mainly non polar amino acids

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14
Q

Transmembrane proteins often contain?

A

Intrachain disulfide bonds and can be glycosylated

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15
Q

Glycocalyx are used for?

A

Cell recognition purposes

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16
Q

What can stain the membrane?

A

Carbohydrate binding proteins called lectins or ruthenium red

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17
Q

Spectrin does what?

A

Provides membrane with shape and structural integrity

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18
Q

Which of the following lipids has a net negative charge at physiological pH?

A

Phosphatidylserine

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19
Q

What is the carbohydrate layer on the outer surface of cells called?

A

Glycocalyx

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20
Q

What type of cell:cell junction would you expect to find at the basal plasma membrane of epithelial cells, connecting them to the basal lamina?

A

Hemidesmosomes

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21
Q

Artificial phospholipid bilayer vesicle formed from an aqueous suspension of phospholipid molecules

A

Liposome

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22
Q

Small region of the plasma membrane enriched in sphingolipids cholesterol

A

Lipid raft

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23
Q

Any glycolipid having one or more sialic acid residues in its structure; especially abundant in the plasma membranes of nerve cells

A

Ganglioside

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24
Q

Having both hydrophobic and hydrophilic regions, as in a phospholipid or a detergent molecule

A

Amphiphilic

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25
Q

The main type of phospholipid in animal cell membranes, with two fatty acids and a polar head group attached to a three carbon glycerol backbone

A

Phosphoglyceride

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26
Q

Lipid molecule with a characteristic four ring steroid structure that is an important component of the plasma membranes of animal cells

A

Cholesterol

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27
Q

Protein that binds tightly to a specific sugar

A

Lectin

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28
Q

The outer coat of a eukaryotic cell, composed of oligosaccharides linked to intrinsic plasma membrane glycoproteins and glycolipids, as well as proteins that have been secreted and reabsorbed onto the cell surface

A

Carbohydrate layer

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29
Q

Abundant protein associated with the cytosolic side of the plasma membrane in red blood cells, forming a rigid network that supports the membrane

A

Spectrin

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30
Q

Protein whose polypeptide chain crosses the lipid bilayer more than once

A

Multipass transmembrane protein

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31
Q

Pigmented protein found in the plasma membrane of Halobacterium halobium, where it pumps protons out of the cell in response to light

A

Bacteriorhodopsin

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32
Q

The complicated cytoskeletal network in the cytosol just beneath the plasma membrane

A

Cortex

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33
Q

Type of lipid linkage, formed as proteins pass through the endoplasmic reticulum, by which some proteins are attached to the noncytosolic surface of the membrane

A

Glycosylphosphatidylinositol anchor

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34
Q

An aqueous pore in a lipid membrane, with walls made of protein, through which selected ions or molecules can pass

A

Channel

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35
Q

The movement of a small molecule or ion across a membrane due to a difference in concentration or electrical charge

A

Passive transport

36
Q

General term for a membrane embedded protein that serves as a carrier of ions or small molecules from one side of the membrane to the other

A

Membrane transport protein

37
Q

Movement of a molecule across a membrane that is driven by ATP hydrolysis or other form of metabolic energy

A

Active transport

38
Q

Driving force for ion movement that is due to differences in ion concentration and electrical charge on either side of the membrane

A

Electrochemical gradient

39
Q

Large superfamily of membrane transport proteins that use the energy of ATP hydrolysis to transfer peptides and a variety of small molecules across membranes

A

ABC transporter

40
Q

Type of ABC transporter protein that can pump hydrophobic drugs out of the cytoplasm of eukaryotic cells

A

Multidrug resistance protein

41
Q

Membrane carrier protein that transports two different ions or small molecules across a membrane in opposite directions, either simultaneously or in sequence

A

Antiporter

42
Q

Transport of solutes across an epithelium, by means of membrane transport proteins in the apical and basal surfaces of the epithelial cells

A

Transcellular transport

43
Q

Carrier protein that transports two types of solute across the membrane in the same direction

A

Symporter

44
Q

The adjustment in sensitivity of a cell or organism following repeated stimulation that allows a response even when there is a high background level of stimulation

A

Adaptation

45
Q

The long lasting increase in the sensitivity of certain synapses in the hippocampus that is induced by a short burst of repetitive firing in the presynaptic neurons

A

Long term potentiation

46
Q

Rapid, transient, self propagating electrical signal in the plasma membrane of a cell such as a neuron or muscle cell: a nerve impulse

A

Action potential

47
Q

Quantitative expression that relates the equilibrium ratio of concentrations of an ion on either side of a permeable membrane to the voltage difference across the membrane

A

Nernst equation

48
Q

A photosensitive ion channel that opens in response to light

A

Channelrhodopsin

49
Q

Voltage difference across a membrane due to the slight excess of positive ions on one side and of negative ions on the other

A

Membrane potential

50
Q

General term for a membrane protein that selectively allows cations such as Na+ to cross a membrane in response to changes in membrane potential

A

Voltage gated cation channel

51
Q

That part of an ion channel structure that determines which ions it can transport

A

Selectivity filter

52
Q

Insulating layer of specialized cell membrane wrapped around vertebrate axons

A

Myelin sheath

53
Q

A K+ transporting ion channel in the plasma membrane of animal cells that remains open even in a resting cell

A

K+ leak channel

54
Q

Long, thin nerve cell process capable of rapidly conducting nerve impulses over long distances so as to deliver signals to other cells

A

Axon

55
Q

Transmembrane protein complex that forms a water filled channel across the lipid bilateral through which specific inorganic ions can diffuse down their electrochemical gradients

A

Ion channel

56
Q

Specialized junction between a nerve cell and another cell, across which the nerve impulse is transferred, usually by a neurotransmitter, which is secreted by the nerve cell and diffuses to the target cell

A

Synapse

57
Q

Small signaling molecule such as acetylcholine, glutamate, GABA, or glycine, secreted by a nerve cell at a chemical synapse to signal to the post-synaptic cell

A

Neurotransmitter

58
Q

Technique in which the tip of a small glass electrode is sealed onto an area of cell membrane, thereby making it possible to record the flow of current through individual ion channels

A

Patch-clamp recording

59
Q

Understand the basic structure, composition, and characteristics of lipid bilayers/membranes (phospholipids, glycolipids, sphingolipids, cholesterol)

A

Lipids are amphiphilic, the major lipids are phosphoglycerides
Lipids make up 50% of membranes
Glycolipids are found in monolayers facing away from the cytosol
Cholesterol is distributed roughly equally between both monolayers

60
Q

Understand what it means for a lipid bilayer to be asymmetrical

A

The outside face of membrane is always different from the inner face of membrane

61
Q

Know what a lipid raft is

A

Formed from a combination of weak protein-protein, protein-lipid, and lipid-lipid interactions to form a lipid raft in the membrane

62
Q

Know what liposomes are

A

Synthetic lipid bilayers

63
Q

Hydropathy plots show what?

A

Hydrophobicity of amino acids thus identifying transmembrane a-helical domains of membrane proteins

64
Q

Basic structure of all cellular membranes include what?

A

Lipid molecules and membrane associated proteins

65
Q

The most abundant membrane lipids are what?

A

Phospholipids

66
Q

What are phospholipids composed of?

A

A polar head group and two hydrophobic hydrocarbon tails

67
Q

The nonpolar tails of phospholipids vary in their what?

A

Length

68
Q

What is a rigid structure attached to a polar hydroxyl head group and short nonpolar hydrocarbon tail?

A

Cholesterol

69
Q

What packs in between phospholipids close to the nonpolar head groups?

A

Cholesterol

70
Q

Cholesterol has an impact on what property of the lipid bilayer?

A

The permeability-barrier properties of the bilayer

71
Q

Cholesterol makes the bilayer less permeable to what?

A

Small water soluble molecules

72
Q

Does cholesterol change the fluid properties of the membrane?

A

No

73
Q

Which are thinner: membranes composed of unsaturated phospholipids or membranes composed of saturated phospholipids?

A

Unsaturated phospholipids

74
Q

Lipids rotate on their what?

A

Axis

75
Q

Lipids exchange positions with neighboring lipids by what?

A

Lateral diffusion

76
Q

Lipids molecules in the plasma membrane associate in specialized lipid sub domains referred to as what?

A

Lipid rafts

77
Q

What regions are enriched with sphingolipids and cholesterol and are involved in organizing membrane proteins?

A

Lipid rafts

78
Q

What are sugar modified lipids?

A

Glycolipids

79
Q

What are localized to the outer leaflet of the plasma membrane bilayer?

A

Glycolipids

80
Q

Assymetry is because sugar addition occurs only within the lumen of the what?

A

ER/Golgi

81
Q

Glycolipids make up how much of all plasma membrane lipids?

A

-5%

82
Q

What localized only to the inner leaflet of a plasma membrane?

A

Phosphotidylserine

83
Q

What kind of proteins span the membrane at least once to generate domains that localized to both sides of the membrane?

A

Transmembrane proteins

84
Q

What proteins pass through the membrane as either an amphipathic alpha-helix or a beta-sheet?

A

Transmembrane proteins

85
Q

What types of proteins are typically localized to the cytosolic side of the plasma membrane?

A

Lipid anchors

86
Q

What are reversible; converting a membrane bound protein into a soluble cytosolic one?

A

Lipid modifications

87
Q

Most membrane proteins span the lipid bilayer as what?

A

Alpha helices