Lectures 3 & 4 JUST Terms Flashcards
(129 cards)
1
Q
Fluid Compartment
A
2 main fluid compartments:
(1) the EXTRAcellular fluid (ECF) outside the cells &
(2) the INTRAcellular fluid (ICF) within the cells
- the dividing wall b/t ECF & ICF is the cell membrane
- the extracellular fluid subdivides further into PLASMA, the fluid portion of the blood, & INTERSTITIAL FLUID, which surrounds most cells of the body
2
Q
Extracellular
A
outside the cells
3
Q
Intracellular
A
within the cells
4
Q
Interstitial
A
which surrounds most cells of the body
5
Q
Plasma
A
the fluid portion of the blood
6
Q
Butter Sandwich
A
early model of the cell membrane structure
- a clear layer of lipids sandwiched b/t 2 dark layers of protein
- NOT accurate b/c it implies that it is homogenous
7
Q
Fluid Mosaic
A
present day model of the cell membrane structure
- proteins are afloat on a sea of lipid
- membrane composed of phospholipid bilayer with proteins inserted wholly or partially into the bilayer
8
Q
Glycolipids
A
molecule that is a combination of carbohydrate & lipid
9
Q
Phospholipids
A
diglycerides with phosphate attached to the single carbon that lacks a fatty acid
- a derivative of glycerides
- are amphipathic molecules
- several different varieties: (R-group, saturation)
- polar head groups towards aqueous sides, non-polar fatty acid tails inside
10
Q
Cholesterol
A
flat molecule, slips b/t fatty acid tails
- a steroid that serves as the basis for steroid hormones; also a key component of membranes
what it does:
- regulates membrane fluidity
- slows diffusion of molecules across membranes
11
Q
Sphingolipids
A
- have fatty acid tails (like phospholipids) but their heads may be either phospholipids or glycolipids
- have longer tails than phopholipids
- tend to aggregate together = lipid rafts
12
Q
Integral
A
are permanently attached (tightly bounded) to the cell membrane
- can be polytopic, bitopic, or monotopic
13
Q
Peripheral
A
attached to one side of membrane by non-covalent interactions; weak
- associate non-covalently with integral proteins, or polar heads of phospholipids
14
Q
Lipid-anchored
A
some of these proteins are covalently bound to lipid tails that insert themselves into the bilayer
15
Q
Cytoskeletal
A
not a membrane protein, but often interact with membrane proteins
- flexible skeleton of fibrous proteins throughout the cytoplasm (give physical strength)
16
Q
Extracellular Matrix
A
membrane proteins & secreted protein found on the extracellular side of membranes
- forms a “husk” around cells
- highly variable glycosylation
- contribute to physical strength of cells
17
Q
Lipid Raft
A
sphingolipids tend to aggregate together = lipid rafts
- rafts also have a high density of cholesterol
- some proteins associate ONLY with lipid rafts, leading to areas of SPECIALIZATION on cell membranes
- for ex: some G-protein coupled receptors
18
Q
Transmembrane Domain (=membrane spanning domain)
A
are regions of a protein that are hydrophobic, so that they prefer to be inserted into the cell membrane such that the parts of the protein on either side of the domain are on opposite sides of the membrane. ?
19
Q
Diffusion/Osmosis
A
diffusion: process of moving solute molecules away from an area of high concentration towards area of low concentration
osmosis: is the diffusion of water
20
Q
Protein Mediated Transport
A
the vast majority of solutes cross membranes with the help of membrane proteins, a process we call mediated transport
21
Q
Vesicular Transport
A
the resulting vesicle attaches to microtubules in the cell’s cytoskeleton & is moved across the cell by this process
- don’t go into it in class
22
Q
Concentration gradient
A
a difference in the concentration of a substance b/t 2 places
23
Q
Kinetic Energy
A
the energy of motion
24
Q
Electrochemical Gradient
A
the combined concentration & electrical gradients for an ion
25
Osmotic Pressure
is the pressure that must be applied to oppose osmosis
26
Hyperosmotic
if solution A has a higher osmolarity (contains more particles per unit volume, is more concentrated) than solution B, we say that solution A is hyperosmotic to solution B
27
Hypoosmotic
solution B, with fewer osmoles per unit, is hyposmotic to solution A
28
Isoosmotic
if 2 solutionss contain the same # of solute particles per unit volume, we say that the solutions are isosmotic
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Hypertonic
if the cell loses water & shrinks at equilibrium
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Hypotonic
if a cell placed in the solution gains water at equilibrium & swells
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Isotonic
if the cell in the solution does not change size at equilibrium
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Penetrating Solute
if the solute particles (ions or molecules) can enter the cell
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Non-Penetrating Solute
particles that cannot cross the cell membrane
34
Channel
is a water filled pore
| - can open to both sides (directly link intracellular & extracellular compartments)
35
Pore
both membranes of the envelope are pierced here & there by round holes
36
Carrier
NEVER form an open channel b/t the 2 sides of the membrane
| - bind to the substrate that they carry
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Symport
2 molecules are transported across the membrane simultaneously across the cell membrane in the same direction
- type of carrier protein
38
Antiport
moving more than 1 solute molecule, but is moving them in opposite directions
- using ATP
- type of carrier protein
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Uniport
allows a single molecule of glucose to move across a membrane (in 1 direction)
- type of carrier protein
40
Facilitated Diffusion
is defined as moving a molecule across the cell membrane via a carrier protein, & the transport does not require energy other than the concentration gradient
41
Primary Active Transport
- uses ATP
- establishes gradients
- sometimes called pumps
- Na+/K+/ATPase is the most widely known ex, but there are others
- Ca2+ ATPase
- H+ ATPase
- H+/K+ ATPase
42
Secondary Active Transport
- does NOT directly utilize ATP as a source of energy
- instead, uses the concentration gradient of 1 molecule/ion to move another against its gradient (acts as energy source)
- Na+-glucose secondary active transporter is a good ex: SGLT-protein
43
ATPase
- b/c primary active transport uses ATP as its energy source, many primary active transporters are known as ATPases
- the suffix -ase signifies an enzyme, & the stem (ATP) is the substrate upon which the enzyme is acting
- these enzymes hydrolyze ATP to ADP & inorganic phosphate (Pi), releasing usable energy in the process
44
Epithelial Transport of Glucose
movement of material from one side of an epithelium to the other
- utilizes:
- facilitated diffusion
- primary active transport
- secondary active transport
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Specificity
the ability of an enzyme or receptor to bind to a particular molecule or a group of closely related molecules
46
Competition
the property of competition is closely related to specificity
- a transporter may move several members of a related group of substrates, but those substrates compete with one another for binding sites on the transporter
- ex:
- GLUT transporter has a "preference" for one or more hexoses, based on its binding affinity
47
Saturation
all active sites on a given amount of protein are filled with substrate & rxn rate
48
Affinity
the degree to which a protein is attracted to its ligand
49
Agonist
a ligand that binds to a protein binding site & ALTERS the state of the protein, resulting in a biological response
- a hormone or neurotransmitter or a drug for example
- can be a drug that mimic a neurotransmitter & in that case consider it an agonist
50
Antagonist
a ligand that REDUCES the action of an agonist (i.e. binds but causes NO biological response)
- also called inhibitors, blockers
51
Tight Junction
cell-to-cell junction in epithelia that does not allow much movement of material b/t the cells
52
Absorption
transfer of substances from the lumen of the kidney or gastrointestinal tract to the extracellular space
53
Active Transport
is the process of moving molecules across a cellular membrane through the use of cellular energy.
54
Apical
the edge of the epithelial tissue facing the lumen or the external environment is called the apical surface. ?
55
Aquaporin
family of membrane water channels
| - can aid in moving H20 (a small uncharged polar molecule) across cell membrane
56
ATP-Gated K+ Channel or KATP Channel
channel that closes when the ATP/ADP ratio increases
57
Basolateral (membrane/surface)
the sides of transporting epithelial cells that face the extracellular fluid
58
Blood Plasma
the liquid matrix of blood, is 25% of the ECF volume
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Carrier Proteins
membrane protein that binds to the molecule it transports
| - NEVER form an open channel b/t the 2 sides of the membrane
60
Channel Proteins
a membrane protein that forms water-filled channels to link intracellular & extracellular compartments
- a water filled pore - can open to both sides
61
Chemical Disequilibrium
although the overall concentrations of the ECF & intracellular fluid (ICF) are =, some solutes are more concentrated in one of the 2 body compartments than in the other
- this means the body is in a state of chemical disequilibrium
62
Chemical Gradient
AKA concentration gradient
| - a difference in the concentration of a substance b/t 2 places
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Chemically Gated Channels
channels whose open gate is controlled by binding to a chemical ligand
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Competitive Inhibitor
molecules that bind to the active site of the enzyme, preventing substrate binding
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Concentration Gradient
a difference in the concentration of a substance b/t 2 places
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Conductor
when separated positive & negative charges can move freely toward each other, the material through which they move is called a conductor
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Cotransporter
a protein that moves more than one kind of molecule at one time
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Depolarized
more +
69
Diffusion
process of moving solute molecules away from an area of HIGH concentration towards are of LOW concentration
- "down the concentration gradient"
- passive (no external energy, just kinetic energy of molecules)
- process continues until equilibrium is reached
70
Dynamic Steady States
A system that is in a steady state remains constant over time, but that constant state requires continual work. ?
71
Electrical Disequilibrium
the inside of cells is slightly (-) relative to the ECF
| - this ionic imbalance results in a state of electrical disequilibrium
72
Electrical Gradient
uneven distribution of electrical change, especially across a membrane
73
Electricity
the rate of flow of negative charges of the conductor. ?
74
Electrochemical Disequilibrium
N/A
75
Electrochemical Gradient
the combined concentration & electrical gradients for an ion
76
Electrodes
a conductor that is used to make contact with a nonmetallic part of a circuit. ?
77
Electrogenic
producing a change in the electrical potential of a cell. ?
78
Epithelial Transport
movement of material from one side of an epithelium to the other
- utilizes:
- facilitated diffusion
- primary active transport
- secondary active transport
79
Extracellular Fluid (ECF)
includes all fluid outside the cells
- the ECF is 1/3 of the body fluid volume
- consists of:
- interstitial fluid (IF)
- plasma
80
Facilitated Diffusion
is defined as moving a molecule across the cell membrane via a CARRIER PROTEIN, & the transport does NOT require energy other than the concentration gradient
- does NOT require ATP, or other solutes
- also sometimes called passive transport
81
Fick's Law of Diffusion
diffusion through a membrane is directly proportional to the surface area & concentration gradient & inversely proportional to the thickness of the membrane & its resistance
82
Fluids
both gases & liquids are considered fluids b/c they flow
83
Gated Channels
a channel that opens & closes in response to stimuli
84
GLUT Transporters
family of facilitated diffusion carriers for glucose & other hexose sugars
85
Ground (Electrical)
s a reference point in an electrical circuit from which voltages are measured ?
86
Hexoses
a 6-carbon sugar
87
Impermeable
not allowing fluid to pass through.
88
Interstitial Fluid
which lies b/t the circulatory system & the cells, is 75% of the ECF volume
89
Intracellular Fluid (ICF)
is 2/3 of the total body water volume
| - material moving into & out of the ICF must cross the cell membrane
90
Ion Channels
may be specific for 1 ion or may allow ions of similar size & charge to pass
91
Leak Channels or Pores
ion channels that spend most of their time in
92
Lipophobic
molecules that cannot diffuse through the phospholipid bilayer
93
Mechanically Gated Channels
a channel that opens in response to mechanical stimuli such as pressure & heat
94
Mediated Transport
movement across a membrane with the aid of a protein transporter
95
Membrane Enzymes
catalyze chemical reaction that take place either on the cell's external surface or just inside the cell
96
Membrane Receptor Proteins
are part of the body's chemical signaling system
97
Membrane Transporters
moves molecules across membranes
98
Molarity (M)
solution concentration expressed as moles of solute per liter of solution
99
Mole
6.02 x 10^23 atoms, ions, or molecules of a substance
100
Monovalent
having a valence of one. ?
101
Mucosal
The moist, inner lining of some organs and body cavities (such as the nose, mouth, lungs, and stomach). ?
102
Na+-K+-ATPase
- pumps 2 K+ ions into cell, removes 3 Na+ ions
in order to do this:
1. hydrolyses ATP
2. several conformational changes
103
Open Channels
channel proteins form an open channel but carrier proteins do NOT
104
Osmolality
is concentration expressed as osmoles of solute per kg of water
105
Osmolarity
describes only the # of solute molecules in a cell (units of Osm)
106
Osmoles
(osmol/L or OsM)
107
Osmometer
an instrument for measuring osmolarity of a fluid ?
108
Osmosis
is the diffusion of water
109
Osmotic Equilibrium
b/c of this free movement of water, the ECF & ICF compartments reach this state
110
Ouabain
cardiac glycoside that specifically inhibits the Na+-K+-ATPase ?
111
Paracellular Transport
through the junctions b/t adjacent cells
112
Passive Transport
AKA facilitated diffusion
- moving a molecule across the cell membrane via a carrier protein, & the transport does not require energy other than the concentration gradient
113
Permeable
allowing liquids or gases to pass through it.
114
Pressure Gradient
The difference in hydrostatic pressure on either side of a membrane. ?
115
Selectively Permeable
cell membranes are selectively permeable, which means that some molecules can cross them but others cannot
116
Serosal Membrane
membranes lining closed internal body cavities. ?
117
SGLT (Na+-Glucose Secondary Active Transporter)
uses the potential energy stored in the Na+ concentration gradient to move glucose against its concentration gradient
118
Simple Diffusion
diffusion across the phospholipid bilayer of a cell
119
Steady States
a state or condition of a system or process (as one of the energy states of an atom) that does not change in time
120
Structural Proteins
maintain cell shape, akin to a skeleton, and they compose structural elements in connective tissues like cartilage and bone ?
121
Tonicity
is a physiological term used to describe a solution & how that solution would affect the cell volume if the cell were placed in the solution & allowed to come to equilibrium
122
Total Body Water
body water is the water content of an animal body that is contained in the tissues, the blood, the bones and elsewhere. ?
123
Transepithelial Transport
epithelium whose primary function is the movement of solutes & water b/t 2 compartments
124
Transport Maximum (Tm)
the maximum transport rate that occurs when all carriers are saturated
125
Transport Proteins
moves molecules across membranes
126
Uniport Carriers
a membrane transport protein that moves only one kind of molecule
127
Voltage-Gated Ca2+ Channel
the route for Ca2+ entry into cells, particularly excitable cells, in response to depolarization. ?
128
Voltage-Gated Channels
a gated channel that opens or closes in response to a change in membrane potential
129
Water Channels
most cells have water channels made from a protein called aquaporin
- water channels are an example of channel proteins
