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Biology 224 > Chapter 5, Membrane Structure, Synthesis, Transport > Flashcards

Chapter 5, Membrane Structure, Synthesis, Transport Flashcards

1
Q

Membrane Structure

A

Two leaflets made of phospholipid bilayers

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2
Q

Fluid Mosaic Model

A
  • double layer of phospholipids
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3
Q

Phospholipids are _________

A

amphipathic

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4
Q

Amphipathic means

A

containing partial + and - charges

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5
Q

Fatty acid tails are _______

A

nonpolar

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6
Q

Phosphate heads are ______

A

polar

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7
Q

Each phospholipid bilayer called a

A

leaflet

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8
Q

Leaflet on outer cell called

A

extracellular leaflet

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9
Q

Leaflet on inside of cell called

A

Cytosolic leaflet

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10
Q

Selective Permeability means

A

-polar molecules cannot pass through hydrophobic membrane center
- non molecules can diffuse through the membrane

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11
Q

There are ____ embedded into phospholipid bilayer

A

proteins

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12
Q

Protein ratio varies from ___-___ times more lipid molecules than protein molecules

A

15-70

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13
Q

_____ determine the exact function of cells different membranes

A

proteins

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14
Q

_____ do the bulk of the membrane’s work

A

proteins

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15
Q

_______ membrane proteins less associated with membrane and are ____ bound to membrane

A

peripheral, loosely

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16
Q

Peripheral membranes bound by _____ or _______ bonds

A

hydrogen or ionic

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17
Q

Peripheral proteins bound to ___________ proteins also called the _______ __ _______

A

transmembrane proteins, heads of phospholipids

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18
Q

Exposed proteins of peripheral proteins are usually _____ for binding

A

polar

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19
Q

Because peripheral proteins only occur on 1/2 leaflets, membranes may be ______ with __________ ______

A

asymmetric, different functions

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20
Q

_______ proteins are more closely associated with the membrane

A

integral

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21
Q

Integral proteins often ____ the membrane

A

span, transverse

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22
Q

Exposed portions of integral proteins usually _____ for binding

A

nonpolar

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23
Q

Two types of integral proteins

A
  • transmembrane
  • lipid-anchored
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24
Q

Transmembrane proteins transverse the membrane with domains forming ______

A

a-helices (alpha)

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25
Q

Regions of alpha proteins occur on ______ ____ of membrane and may be bound to _________

A

both sides, cytoskeleton

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26
Q

Lipid anchored proteins have a lipid _____ attached to the protein

A

covalently

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27
Q

Lipid is inserted into phospholipid bilayer to ______ the protein

A

anchor

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28
Q

Phospholipids in the membrane are… to each other

A

NOT covalently bound

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29
Q

The phospholipids are _________________ within the membrane

A

free to move

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30
Q

Phosophlipid can move from one end of cell to other in…

A

less than a second

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31
Q

______ seconds in a eukaryotic cell

A

5-10

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32
Q

Phospholipids cannot move…

A

between leaflets

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33
Q

Special protein needed to move phospholipids between leaflets using ATP is

A

Flippase

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34
Q

most common phospholipids have an _____ number of carbons

A

even (18-20 in the tails)

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35
Q

Up to 25% of the lipids in animal cell membranes may be ___________

A

cholesterol

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36
Q

The membrane is more fluid if…

A

there are fewer hydrophobic interactions

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37
Q

There will be fewer hydrophobic interactions with… (3)

A
  • shorter hydrocarbon chains
  • more unsaturated hydrocarbon chains (more kinks in chain)
  • more cholesterol makes it MORE fluid at LOW TEMP
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38
Q

Phospholipids cannot flip flop between leaflets because of their _______

A

polarity

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39
Q

membrane ______ can also diffuse/move throughout the membrane

A

proteins

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40
Q

Some proteins exposed to the cytoplasm attach to ______, anchoring them in place

A

cytoskeleton

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41
Q

Carbs in membranes only occur as _______ and __________

A
  • glycolipids
  • glycoproteins
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42
Q

Carbs in membranes only occur in the _______ leaflet of plasma membrane

A

exterior (extracellular)

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43
Q

Glycoproteins and Glycolipids in plasma membrane can act as ______

A

antigens, which identify cells of organisms

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44
Q

Glycoproteins and Glycolipids in plasma membrane can also label…

A

proteins with signals for cellular destinations

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45
Q

Glycocalyx is a

A

thick layer of carbs outside plasma membrane

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46
Q

Purpose of glycocalyx

A

shield cell from immune system of other cells

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47
Q

Phospholipids are synthesized by the

A

smooth ER

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48
Q

Phospholipids can be spread throughout the Endomembrane System by _______ _________

A

lateral diffusion

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49
Q

Membranes of nucleus, ER, golgi, plasma membrane, mitochondria, and chloroplasts are either _________ ______ or connected by ________

A

directly connected, connected by vesicles

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50
Q

Lipid Exchange proteins can…

A

extract lipid from one membrane, diffuse through cytoplasm, and insert it into any other membrane

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51
Q

The _________ and __________ both synthesize various types of proteins which are transferred to other organelles by lipid exchange proteins

A

mitochondria, chloroplast

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52
Q

Most transmembrane proteins are synthesized in …

A

rough ER

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53
Q

___________ _________ left in ER membrane as they are synthesized, forming transmembrane proteins

A

Hydrophobic alpha helices

54
Q

From ER, proteins moved to other membranes by ______

55
Q

Glycosylation of proteins occurs in _______ _____ with modifications in the _______

A

rough ER, golgi

56
Q

Oligosaccharides are synthesized in the…

A

lumen of the ER, on a dilichol lipid then transferred as unit to R/Side group of acid on proteins

57
Q

The golgi _______ and ______ a lot of proteins

A

synthesizes and modifies

58
Q

Proteoglycans are a type of

A

glycoprotein

59
Q

Proteoglycans are often _______ from the cell to help form the ______ ______

A

secreted, extracellular matrix

60
Q

Biological membranes are ______ ___________ because of their ___________ interior

A

selectively permeable, hydrophobic

61
Q

Molecules passed through membranes by two types of transport

A

active, passive

62
Q

two types of passive transport

A

simple/passive, facilitated diffusion

63
Q

In passive transport..

A

molecules move down or with concentration gradient

64
Q

Active transport…

A

molecules move up or against concentration gradient, require ATP

65
Q

Two types of active transport

A

primary, secondary

66
Q

Passive transport depends on the ______ energy of the solute molecule

67
Q

Kinetic energy is…

A

energy of molecules in motion

68
Q

All molecules are in ________ ________

A

constant motion

69
Q

Molecules in motion…

A

tend to evenly distribute themselves with time

70
Q

Simple/passive is ____ movement (from high to low conc.)

71
Q

Passive usually occurs for ____ molecules or small _____ molecules

A

nonpolar, uncharged

72
Q

The molecules diffuse directly through __________ ___________

A

phospholipid bilayer

73
Q

Primary examples of passive diffusion of molecules moving directly through membrane are diffusion of gases…(3)

A

oxygen, nitrogen, carbon dioxide

74
Q

Rate of diffusion depends on (4)

A
  • electrical charge
  • temperature
  • concentration
  • molecular size
75
Q

With a high different in concentration, molecules will move…

76
Q

Diffusion over ______ distances is very effective

77
Q

_______ molecules can diffuse throughout the cell, ________ molecules needs special means to transport them

A

nonpolar, polar

78
Q

Facilitated diffusion is _________ transport

79
Q

facilitated diffusion passive because…

A

still moving from high to low

80
Q

Facilitated diffusion used to move

A

polar and macromolecules

81
Q

Facilitated diffusion transports using ________

82
Q

Proteins must be ________ or __________ proteins

A

channel, carrier/transport

83
Q

Channel proteins are __________ proteins that form channels through membrane through which certain molecules can diffuse

A

transmembrane

84
Q

Channel proteins may be _____ and only transport when ____ is open

A

gated, gate

85
Q

______-gated channels open when _____ ______ is bound

A

ligand, signal molecule (ligand)

86
Q

_____-gated channels open when membrane is….

A

voltage, depolarized by change in electrical charge across membrane

87
Q

transporter proteins bind to solute usually by a ______ change in protein

A

conformational (shape)3

88
Q

3 types of transporters are

A

uniport
symport
antiport

89
Q

Uniport

A

transports one (same kind) solute molecule in one direction

90
Q

Symport

A

transports two different kinds of molecules in same direction

91
Q

Antiport

A

Transports two different kinds in two different directions (one at a time)

92
Q

Primary Active Transport is…(3)

A
  • transport of substance with pump
  • against concentration gradient
  • with DIRECT expenditure of energy
93
Q

_____ is often energy source used

94
Q

The __________________ is classic example of Primary AT

A

Sodium Potassium pump

95
Q

Na/K pump : Pumping two cation at uneven rates results in…

A

electrical charge across plasma membrane

96
Q

Secondary Active Transport

A

Uses AT of molecule to drive transport of 2nd molecules AGAINST gradient by using left over ATp

97
Q

Secondary AT is different because…

A

no ATP EXPENDED DIRECTLY, uses ATP already made, molecule piggy backs and flows against concentration gradient

98
Q

Because of active transport something flowed against its gradient, its imbalanced and wants to equalize, so…

A

secondary AT uses energy from primary to go against gradient and keep it from equilizing

99
Q

Osmosis is …

A

diffusion of water through semipermeable membrane

100
Q

Water sometimes diffuses through special pores in membranes called

A

aquaporins

101
Q

Aquaporins found in (3)

A

plant cells, kidney cells, RBC of animals

102
Q

Water molecules pass ____ ___ through the pore, which excludes other molecules

A

single file

103
Q

Water molecules can also hitchhike, bound to ______ when they pass through pores

104
Q

There are three conditions into which a cell may be placed

A

Hypotonic
Hypertonic
Isotonic

105
Q

Hypotonic, Hypertonic, Isotonic refer to ______

106
Q

Isotonic means

A

solution has same solute and same water concentration, cell volume DOES NOT change

107
Q

Hypertonic means

A

Solution has higher solute concentration, lower water concentration

Cell has higher water concentration, so water goes out of cell to equalize, cell looses volume

108
Q

Hypotonic means

A

Solute has lower solute concentration, higher water concentration

Cell has lower water concentration, water goes into cell, cell gains volume

109
Q

Endocytosis

A

brings large sized materials into cell using Vesicle formation

110
Q

______ ________ endocytosis uses receptors to concentrate materials before brigning them in

A

receptor mediated

111
Q

Receptors perfectly fit thing to bring in, so certain number of receptors fill up and then…

A

that signals cell to bring cargo in

112
Q

After vesicles bring material in, material can fuse with a _____ ________

A

primary lysosome

113
Q

Macromolecules are digested to _______ before they are transported to the cytoplasm

114
Q

Exocytosis

A

discards material from cell using vesicles

115
Q

Exocytosis also add ________ to the plasma membrane

A

phospholipids

116
Q

_____ is famous for secreting material

117
Q

cells produce extracellular matrix for ______ and ______

A

strength and support

118
Q

Multicellular organisms use cell ________ to hold adjacent cells together

119
Q

Most cell junctions composed of _____

120
Q

Anchoring junctions made up of

A

cadherin and integrin

121
Q

Tight junctions made up of

A

occludin and claudin

122
Q

Gap junctions made up of

123
Q

Connect to elements of _____ in adjacent cells

A

cytoskeleton

124
Q

(anchoring junction) cadherin are ___ proteins connected to…

A

fibrous, actin microfilaments in the cytoplasm

125
Q

Cadherin extends into extracellular matrix where Ca2+ helps to…

A

bind them together

126
Q

Integrins are composed of… which then bind to…

A

two subunits, bind to actin microfilaments in cytoplasm

127
Q

In extracellular matrix, integrin binds to ______ which then bind to elements of the matrix such as ____ fibers

A

fibronectin (wishbone), collagen

128
Q

Tight junctions form ____ between cells

129
Q

Tight junctions (2)

A
  • limit movement of materials through intercellular spaces
  • Limit movement of proteins within the membrane
130
Q

Gap junctions form _____ connecting the _____ of two adjacent cells

A

channels, cytoplasm

131
Q

Gap junction function

A

allow passage of small ions and small molecules for communication between cells

Biology 224 (18 decks)

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