Cell Membrane, Membrane Transport, and Membrane Potential Flashcards

1
Q

______ functions to Separate cytoplasm from ECF, Regulate exchange between ECF and Cytoplasm, Communicate with other cells, and Provide structural attachments between cells or between cell and extracellular matrix.

A

Plasma Membrane

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2
Q

Plasma membrane structure is described by ____ model

A

Fluid Mosaic Model

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3
Q

What are the 4 different types of organic molecules that make up the plasma membrane?

A

phospholipids, steroids, proteins, and carbs

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4
Q

______ are Amphipathic, Organized into a bilayer, and Functions: Creates Barrier

A

Phospholipids

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5
Q

What are the heads of phospholipid polar or non-polar?

A

Polar

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6
Q

What are the tails of phospholipid polar or non-polar?

A

Non-polar

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7
Q

Hydrophobic substances: Small, nonpolar molecules, Ex. (Gases (O2, CO2), Fatty acids, steroids, Lipophilic substances•Ex. Ethanol, and Water are _______ for phospholipids (Permeable or non-permeable)

A

Permeable

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8
Q

Larger molecules, Polar molecules, and Charged substances (Glucose, Ions, Amino acids, and Proteins) are _____ for phospholipids (Permeable or non-permeable)

A

Non-permeable

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9
Q

_____ are incorporated into plasma membranes Help keep membrane fluid over a wide range of temperatures and Help to make membrane water tight

A

Cholesterol

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10
Q

For proteins ____ determines function

A

Shape

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11
Q

What are the factors that alter protein shape?

A

Mutations, pH, Temp, Osmolality, and Covalent/Allosteric Modulation

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12
Q

A mutation alters the ____ structure of the protein

A

Primary

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13
Q

Changes in ph, Temp, or Osmolaltiy alters the ______ structures of the proteins and causes _____

A

Secondary, Tertiary, and Quaternary; denaturation

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14
Q

Covalent/Allosteric Modulation changes the ____ structures of a protein

A

Secondary, Tertiary, and Quaternary

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15
Q

What are the 3 structural classifications of a protein?

A

Transmembrane, Integral, and Peripheral

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16
Q

______ Bind to specific chemical signals (ligands) and transmit that information to the cytoplasm

A

Receptors

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17
Q

Shape of the binding site determines what will bind; Each type of protein, in general, will interact with only one type of substance or class of substances

A

Specificity

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18
Q

______ refers to the fraction of total binding sites that are occupied at any given time; Dependent on [protein] and the [substance]

A

Saturation

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19
Q

A _______ is a chemical substance (exogenous ligand) that binds to the active site of the protein and blocks the endogenous ligand from binding

A

competitive inhibitor

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20
Q

A chemical substance that comes from outside the body

A

exogenous ligand

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21
Q

A _____ will also activate a receptor

A

agonist

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22
Q

A ____ will block receptor activity

A

antagonist

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23
Q

Response of a cell to a chemical signal is _____ mediated

A

receptor mediated

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24
Q

If there is no receptor, there is ____ response

A

no response

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25
Q

If 2 different ligands bind to the same response, they will elicit _____ response

A

same response

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26
Q

If one ligand binds to 2 different receptors, it will elicit ____ response

A

2 different responses

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27
Q

Strength/Ease of ligand-receptor binding; proportionate to # ligands bound to receptors at any given

A

Receptor Affinity

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28
Q

____ is the ligand concentration where half of the receptors are occupied

A

Kd

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29
Q

Affinity is ____ to Kd

A

inversely related

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30
Q

Transmembrane proteins with a 3D shape that forms a tiny fluid filled pore connecting ECF and Cytoplasm

A

Channels

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31
Q

_______ function in Facilitated diffusion of ions into and out of cell (passive; does not require energy); Can be somewhat specific (Ca++ channel, Na+ channel, Cl-channel, cation channel, etc.)

A

Channels

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32
Q

Always open and ions freely flow through via facilitated diffusion; Creates “Leak Currents”

A

Open Channels

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33
Q

Spend most of their time in the closed state, and will open only when stimulated; Three types: a. Chemically gated b. Mechanically gated c. Voltage gated

A

Gated Channels

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34
Q

____ modulation is seen in ligand-gated channels; displays non-covalent bonding and don’t need a catalyst

A

Allosteric modulation

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35
Q

____ modulation uses kinases and phosphatases; displays covalent bonding and needs a catalyst

A

Covalent modulation

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36
Q

Transmembrane protein that moves hydrophilic building blocks across the plasma membrane via facilitated diffusion (passive; does not require energy); changes shape

A

Carriers

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37
Q

Transmembrane protein that moves ions and hydrophilic building blocks across the plasma membrane via active transport (Active; requires energy).

A

Active Transporters

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38
Q

____ proteins Forms cell to cell attachments that hold adjacent epithelial cells together

A

Structural Proteins

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39
Q

_____ junctions Prevents intercellular movement of fluid and dissolved substances

A

Tight Junctions

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40
Q

_____ are junctions for Structural Support

A

Desmosomes

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41
Q

_____ junctions function in Cell to Cell communication via ions

A

Gap Junctions

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42
Q

Integral membrane, transmembrane, or peripheral membrane proteins that catalyze specific chemical reactions either on the extracellular surface of cell or inside cell.

A

Enzymes

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43
Q

______ are Attached to extracellular surface of membrane lipids and proteins

A

Carbohydrates

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44
Q

made up of Glycolipid and carbs; Plays important role in enabling cells to identify and interact with each other.

A

Glycocalyx

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45
Q

In ____ transport, No energy required; Down gradients (high to low; ΔC, ΔP or ΔE); Types-Diffusion-Osmosis-Bulk Flow

A

Passive Transport

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46
Q

In ____ transport, Energy required; Up gradients (low to high); Types-Active Transporters-Bulk (Vesicular) Transport

A

Active Transport

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47
Q

Molecules in a fluid are continuously and randomly bouncing aroundRate of movement proportional (T) and inversely related to (Mass)

A

Random thermal motion –

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48
Q

Movement of substances other than water down a gradient (ΔC; ΔE or ΔP; high to low). Net movement stops at equilibrium, Random movement is continuous, and is Substance specific

A

Diffusion

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49
Q

____ transport moves the system towards equilibrium

A

Passive transport

50
Q

Type of diffusion: Hydrophobic/Lipophilic SubstancesMove directly through phospholipid bilayerSlowerUnregulatedDoes not require a plasma membraneDiffusion rate α (ΔG)(T)(A)/(R)(D)

A

Simple Diffusion

51
Q

Type of diffusion: Hydrophilic/Lipophobic SubstancesRequire membrane channels or carriersFasterRegulated (specificity, saturation, competition)Requires plasma membrane Diffusion Rateions α (ΔG)(T)(#Channels)(Popen)Or molecules α (ΔG)(T)(#Carriers)

A

Facilitated Diffusion

52
Q

Is Na higher on the inside or outside of cell?

A

Outside

53
Q

Is K higher on the inside or outside of cell?

A

Inside

54
Q

Is Ca higher on the inside or outside of cell?

A

Outside

55
Q

Is Mg higher on the inside or outside of cell?

A

Inside

56
Q

Is Cl higher on the inside or outside of cell?

A

Outside

57
Q

Is HCO3 higher on the inside or outside of cell?

A

Outside

58
Q

Is Phosphates higher on the inside or outside of cell?

A

Inside

59
Q

Is glucose higher on the inside or outside of cell?

A

Outside

60
Q

Is amino acids higher on the inside or outside of cell?

A

Inside

61
Q

Is pH higher on the inside or outside of cell?

A

Outside

62
Q

Are proteins higher on the inside or outside of cell?

A

Inside

63
Q

T/F: It takes about 2 hours to synthesize proteins; many are synthesized in advance and stored in an inactive form, activated when needed; provides a means for immediate protein regulation

A

True

64
Q

The interaction between substance and protein binding site follows the ____ model

A

Mass Action Model

65
Q

Movement of H2O across a plasma membrane down a [free H2O] gradient.; Water movement facilitated by aquaporinsWater permeability can be regulated[free H2O] α 1 / [solute]

A

Osmosis

66
Q

T/F: Water molecules will move passively down free water gradient (toward the area with a higher solute conc.)

A

True

67
Q

Does osmotic equilibrium always equal volume equilibrium?

A

No

68
Q

T/F: Osmosis is substance specific

A

False

69
Q

Only _____ substances determine water movement via osmosis

A

impermeable

70
Q

The total (free) solute concentration of a solution is known as its _____ (permeable and impermeable solute).

A

osmolarity

71
Q

One ____ is equal to 1 mol of solute particles

A

osmol

72
Q

1 M solution of glucose has a concentration of ____ Osm (osmol per liter), whereas a 1 M solution of sodium chloride is ____ Osm ( osmol of solute per liter of solution).

A

1 Osm; 2 Osm

73
Q

bathing solution Osm = cytosolic Osm2.

A

Isosmotic

74
Q

bathing solution Osm < cytosolic Osm3.

A

Hyposmotic -

75
Q

bathing solution Osm > cytosolic Osm

A

Hyperosmotic -

76
Q

defined by the number of impermeable substances only; determines the direction of H2O movement via Osmosis

A

Tonicity

77
Q

Concentration of impermeable solute = cell cytosol2. Cells in this bathing solution will have no net Δ volume

A

Isotonic solution

78
Q

Concentration of impermeable solute < cell cytosol2. Cells in this bathing solution will gain water and swell

A

Hypotonic solutions

79
Q

Concentration of impermeable solute > cell cytosol2. Cells in this bathing solution will lose water and shrink

A

Hypertonic solutions

80
Q

_____ is the pressure required to stop the flow of water in to a compartment

A

Osmotic pressure

81
Q

Ethanol, fatty acids, O2, CO2, steroids, Urea, and glucose are ____ solutes (permeable or impermeable)

A

Permeable

82
Q

Ions and proteins are ____ solutes (permeable and impermeable)

A

Impermeable

83
Q

Urea and glucose are ____ on the cellular level but _____ on the systemic level and RBC

A

Impermeable on cellular; permeable on systemic

84
Q

Water is the most abundant molecule in your body accounting for _____ % of body weight

A

60%

85
Q

How much of body weight is due to water in ICF?

A

40%

86
Q

How much of body weight is due to water in interstitial fluid?

A

15%

87
Q

How much of body weight is due to water in blood plasma?

A

5%

88
Q

The volume of water in the intracellular vs. extracellular spaces is ______.

A

unequal

89
Q

The osmolarity of the extracellular and intracellular spaces is _____.

A

equal

90
Q

_____ requires an input of energy

A

Active transport

91
Q

Transmembrane protein that moves ions and hydrophilic building blocks across the plasma membrane up a ΔC (requires energy); Classification Based on: Number of substances being transported, Directions substances are transported, and Source of energy for transport

A

Active transporters

92
Q

Active transport that transport only one of substrate

A

Uniport

93
Q

Moves more than one substance and all substances moving in same directions

A

Symporters

94
Q

Moves more than one substance and all substances moving in different directions

A

Antiporters

95
Q

In ______ active transport, energy comes directly from breakdown of ATP

A

Primary (1°) Active

96
Q

In ______ active transport, energy released from one substance moving down a gradient is used to pump a second substance up a gradient.

A

Secondary (2°) Active

97
Q

____ active transport moves 1 substance up a gradient and 1 down

A

Secondary active

98
Q

_____ Moves large substances across plasma membrane, Gradient Independent, and Requires Energy; how cell modifies composition of plasma membrane

A

Vesicular Transport

99
Q

Brings substances into cell•Forms vesicle•Removes membrane from Plasma Membrane

A

Endocytosis

100
Q

Removes substances from cell•Vesicle fuses to membrane•Adds membrane to Plasma Membrane

A

Exocytosis

101
Q

Plasma has more _____ than interstitial fluid making it different

A

protein

102
Q

Charge difference across the plasma membraneCreated by unequal distribution of anions and cations across the cell membraneCharge separation = source of energy

A

Membrane potentials (Vm)

103
Q

_____ is the charge difference across the plasma membrane when the cell is at rest.

A

Resting Membrane Potential

104
Q

What is normal resting membrane potential

A

-70 mV

105
Q

The sign of the membrane potential represents the charge ____ the cell

A

inside

106
Q

Creates electrical gradients for movement of ions into/out of cells; Opens or closes gated ion channels; Regulates exocytosis.

A

Membrane potentials

107
Q

In ____ gradient, Ions will move passively down concentration gradients

A

Chemical Gradient

108
Q

In ____ gradient, ions will move passively down electrical gradients

A

Electrical gradients

109
Q

____ gradient is characterized by FDRIon = (ΔEC)(T)(#ion channels)(Popen)

A

Electrochemical Gradient

110
Q

_____ OF THE ELLECTRICAL GRADIENTDepends on the valence of the ion and the magnitude of the membrane potential.

A

STRENGTH

111
Q

Vm that creates an ΔE that is equal in strength but opposite in direction of the ΔC (ΔE-ΔC=0).Electrochemical EquilibriumNo net ion movement through channels via facilitated diffusion

A

Equilibrium Potential (Eion) =

112
Q

Calculates the equilibrium potential (E) when ion concentrations are known.

A

The Nernst Equation

113
Q

What is the formula for Nernst Eq?

A

Eion (mV) = (61/Z) log ([ion]ECF / [ion]ICF)

114
Q

T/F: At a cell’s resting membrane potential, the equilibrium potentials for Na+, K+, Cl- & Ca++are such that when an ion channel for one of these ions opens, the ions follow their concentration gradient.

A

True usually

115
Q

Vm becomes less negative than rest.

A

Depolarization –

116
Q

Vm change that restores resting Vm.

A

Repolarization –

117
Q

Vm becomes more negative than rest

A

Hyperpolarization –

118
Q

T/F: When Ion moves down EC gradient, Vm moves toward Eion, decreasing the EC gradient for ion movement and subsequently decreasing rate of ion movement via facilitated diffusion.

A

True

119
Q

What are the 2 determinants of resting membrane potential?

A

Relative ion permeabilities and Na/K ATPase activity

120
Q

To change _______, Change the membrane’s permeability to an ion (open/close a channel, or change activity of an active transporter); Change the ion concentration gradient across the membrane

A

Membrane potential