2.08 Membranes and Transport System Flashcards

1
Q

Vesicles surrounded by a lipid bilayer with an aqueous interior

A

Liposomes

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2
Q

Tested as red cell substitute, to deliver encapsulated drugs and as vectors for gene therapy

A

Liposomes

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3
Q

Membranes lipids are composed of _______

A

Phospholipid
Glycolipid
Cholesterol

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4
Q

2 types of membrane proteins

A

Integral protein

Peripheral protein

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5
Q

Permanently bound, fixed in the membrane

A

Integral protein

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6
Q

Do not penetrate the hydrophobic layer of membrane

A

Peripheral protein

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7
Q

___ are asymmetrically distributed in the membranes

A

Lipids

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8
Q

ATP-dependent lipid class of transporters specific for phosphatidylserine and phosphatidylethanolamine

A

Flippase

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9
Q

Outward directed ATP-dependent transporter; non-specific for phospholipid

A

Floppase

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10
Q

Most membrane lipid and protein can freely move through the membrane plane

A

Lateral mobility

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11
Q

Fluidity of membrane depends on ____ and ___

A

Temperature

Lipid composition

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12
Q

Temperature at which membrane starts to become fluid from gel-like consistency

A

Transition temperature

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13
Q

Interactions between hydrophobic tails ____ fluidity

A

Decrease

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14
Q

Increase in fluidity , ___ in permeability to water and other small hydrophilic molecules

A

Increase

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15
Q

Membrane allows adjustments of cell compositions and functions

A

Selectivity

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16
Q

Steroid, amphipathic, found in animal cells, found in both leaflets of bilayer

A

Cholesterol

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17
Q

Major lipid component of cell membrane, amphipathic, phosphatidylcholine, sphingomyelin

A

Phospholipid

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18
Q

Cholesterol (increases/decreases) fluidity if the temperature is below the transition temperature

A

Increases

It interferes with the interaction of hydrocarbon fails of fatty acids

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19
Q

As the fluidity increases, the permeability to water and other small hydrophilic molecules ______

A

Increases

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20
Q

As the concentration of unsaturated fatty acids in the membrane increases, fluidity _____

A

Increases

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21
Q

Cholesterol (increases/decreases) fluidity if the temperature is above the transition temperature

A

Decreases

It limits the disorder because cholesterol is more rigid than the hydrocarbon tails of the fatty acids

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22
Q

Contains choline head group and glycerophosphoric acid

Precursor of sphingomyelin

A

Phosphatidylcholine

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23
Q

Contains predominantly the longer chain fatty acids, with carbon length of 24
Serves in signal transduction and insulation of nerve fibers

A

Sphingomyelin

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24
Q

Least common of the membrane lipids

Always found on the leaflet membrane

A

Glycolipid

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25
Q

Involved in the cell identity

A

Glycolipid

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26
Q

Penetrate bilayer or span membrane

A

Integral protein

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27
Q

2 types of integral protein

A

Transmembrane protein

Covalently tethered integral protein

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28
Q

Single pass or multiple pass

A

Transmembrane protein

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29
Q

Integral proteins are synthesized in ____

A

RER

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30
Q

Functions of integral proteins

A
Enzymatic
Receptor
Transport
Communication
Adhesion
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31
Q

Proteins that do not penetrate the whole membrane

Not covalently linked to other membrane compounds

A

Peripheral proteins

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32
Q

Peripheral proteins are synthesized in ____ and ____

A

Cytoplasm (cytoplasmic-inner- side)

ER and exocytosed (extracellular-outer-side)

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33
Q

____ play a role in cell-to-cell recognition

A

Membrane carbohydrates (oligosaccharides)

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34
Q

Specialized region in the membrane that play a role in signaling
Composed of cholesterol and sphingomyelin

A

Lipid rafts

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35
Q

Little caves
Groups of integral protein that contain caveolin
Transcellular pathway or signaling process

A

Caveolae

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36
Q

Intercellular juction that serves as barrier to prevent the molecules and ions to move freely between cells

A

Tight junctions

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37
Q

Constitutive, regulated

A

Exocytosis

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38
Q

Preferably at clathrin coated pits

A

Endocytosis

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39
Q

Processes involved in the cell membrane

A

Exocytosis
Endocytosis
Phagocytosis/pinocytosis
Small solute movement

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40
Q

Allow direct flow of molecules from one cell to another

A

Gap junction

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41
Q

Movement across biological membrane, does not require energy

A

passive diffusion

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42
Q

Tendency of the molecules of any substance to spread out in available space

A

Diffusion

43
Q

Movement may be random or directional

Across permeable membrane

A

Diffusion

44
Q

Molecules with limited permeability can diffuse though bilayer with the aid of ____

A

Transported protein

45
Q

Solutes move down a gradient of electrochemical potential in combination with a carrier

A

Facilitated diffusion

46
Q

Movement of water

A

Osmosis

47
Q

Enzymes couple net solute movement across a membrane to ATP hydrolysis

A

Active Transport

48
Q

In active transport, Km for carrier loading is asymmetrical. It is ____ on the side of the membrane toward which active transport occurs

A

Higher

49
Q

Transport system is an ATPase

A

Primary active transport

50
Q

Utilizes the Na+ electrochemical gradient

A

Secondary active transport

51
Q

4 Primary active transporters

A

P-type
V-type
F-type
ATP-binding casette transporter

52
Q

De/phosphorylated during the transport of Na, K, Ca

A

P-type

53
Q

Proton pumps responsible for acidification of the interior of lysosomes, endosomes, Golgi vesicles and secretory vesicles

A

V-type

54
Q

Present in mitochondria, translocate protons at the expense of ATP hydrolysis

A

F-type

55
Q

Catalyze ATP-dependent vectorial movement of diverse substances

A

ABC transporter

56
Q

Multidrug resistance family
Sulfonylurea receptor
Cystic fibrosis transmembrane conductance regulator

A

ABC transporter

57
Q

Atypical ABC transporter

Indirectly regulates ____ channels

A

Sulfonylurea receptor; Potassium

58
Q

Utilize a secondary structure of energy such as transmembrane electrochemical gradient of either sodium or hydrogen

A

Secondary active transport

59
Q

Involves interaction with the solute and changing shape

A

Carrier transport protein

60
Q

Allows the solute to pass through without binding and changing shape

A

Channel transport protein

61
Q

Ion carriers or channels produced by microorganisms

A

Ionophores

62
Q

Carriers exhibit _____ with respect to solute concentration

A

saturation kinetics

63
Q

Carriers will only recognize a specific structure

A

Stereospecificity

64
Q

Characteristics of carrier protein

A
Saturation kinetics
Stereospecificity
Susceptible to inhibition
Susceptible to hormonal control
Influence of insulin on the GLUT
Influence of aldosterone on the Na-K transporter
65
Q

Transport rate mediated by carrier is (faster/slower) than the transport with no catalyst

A

Faster

66
Q

Transport rate mediated by carrier is (faster/slower) than w/ channels

A

Slower

67
Q

Too large to move across the membrane

Transmembrane proteins with fixed topology

A

Carrier proteins

68
Q

Classes of carrier protein

A

Uniport
Symport
Antiport

69
Q

Facilitated diffusion

Carriers mediate transport of a single solute

A

Uniport

70
Q

GLUT 1

Valinomycin

A

Uniport

71
Q

Large integral protein

Predicted via hydropathy plots to have 12 transmembrane helices

A

GLUT1

72
Q

Carrier for potassium; reversibly binds a single potassium ion

A

Valinomycin

73
Q

Can undergo conformational change associated with bound substate
Mediate net solute transport

A

Uniport

74
Q

Carriers bind 2 dissimilar solutes (substrate) and transport them together across a membrane

A

Symport

75
Q

In symport, transport of the 2 solutes is _____

A

Obligatorily coupled

76
Q

glucose-sodium symport

A

Symport

77
Q

A gradient of 1 substrate, usually an ion, may drive uphill transport of cosubstrate

A

Symport

78
Q

Carrier exchange one solute for another across a membrane

A

Antiport

79
Q

ADP/ATP exchanger

A

Antiport

80
Q

Small, very hydrophobic intrinsic membrane proteins with several highly conserved AA sequences

A

Aquaporin

81
Q

Allow water molecules to enter cell

A

Aquaporin

82
Q

Caused by mutation in the gene encoding for aquaporin (AP-2)

A

Nephrogenic diabetes insipidus

83
Q

Usually consists of large protein complexes with multiple transmembran alpha-helices

A

Cellular channels

84
Q

Form of allosteric regulation.

A

Control of channel gating

85
Q

Conformational changes associated with channel opening may be regulated by

A

Voltage
Binding of ligand
Membrane stretch

86
Q

An unusual peptide, with alternating D and L amino acids

A

Gramicidin channels

87
Q

Channels cycle between open and closed conformations

A

Ion channels

88
Q

Many ions flow through a channel, each it opens

A

Ion channels

89
Q

Higher transport rates for ____

A

Channels

90
Q

The membrane itself wraps around particle and pinches off a vesicle inside the cell

A

Endocytosis

91
Q

Type of endocytosis in which an entire cell is engulfed

A

Phagocytosis

92
Q

Type of endocytosis in which external fluid is engulfed

A

Pinocytosis

93
Q

The material to be transported binds to certain specific molecules in the membranes

A

Receptor-mediated endocytosis

94
Q

Large molecules that are manufactured in the cell are released through cell membrane

A

Exocytosis

95
Q

Causes short-limbed dwarfism

Cartilage is not converted to bone through bone ossification

A

Achondroplasia

96
Q

Achondroplasia is due to mutation of ___

A

Fibroblast Growth Factor 3

97
Q

Genetic mutation in the low density lipoprotein receptor

A

Familial hypercholerostemia

98
Q

Autosomal recessive disease that leads to chronic lung inflammation, infertility in males and pancreatic insuffiency

A

Cystic fibrosis

99
Q

Cystic fibrosis is due to gene mutation in ___ , an ABC transporter, which acts as a chloride ion channel

A

Cystic Fibrosis Transmembrane Regulator

100
Q

Autosomal recessive disorder copper excretion

Accumulation of copper in the body

A

Wilson disease

101
Q

Wilson disease is caused by defect in the ____, encodes for ATP-dependent P-type ATPase that transports copper ions from the liver to the bile canaliculi

A

ATP7/B Gene

102
Q

Happens when cancer cells interact with oligosaccharides in glycoproteins and glycolipids in the cell membrane (selectin, integrin)

A

Metastasis of cancer cells

103
Q

Leads to polyuria

Water is not reabsorbed in the kidneys

A

Nephrotic Diabetes Mellitus

104
Q

____ in the apical membrane does not respond to vasopressin&raquo_space; does not allow permeability in the collecting duct cells, thus preventing water reabsorption that leads to polyuria

A

Aquaporin-2