MCP 25: Solute Transport Flashcards

1
Q

extrinsic proteins

A

proteins attached to membrane

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2
Q

intrinsic proteins

A

proteins embedded in a membrane; may be anchored by cytoskeletal proteins; cannot be removed without destroying membrane

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3
Q

diffusion

A

the transport of molecules from an area of high concentration to an area of low concentration; water, hydrophobic molecules (nitrogen, oxygen, CO2, benzene) or small nonpolar molecules (H2O, urea, maybe glucose) can passively diffuse through the membrane without ion channels; ions CANNOT move through membrane without channels.

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4
Q

flux

A

the movement of ions from high to low concentration, measured in amount of particles per time

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5
Q

Fick’s law

A

Ji=DiA(C1-C2)/x; concentration gradient and flux related linearly

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6
Q

Fick’s law applied to plasma membrane

A

Jx=Px(Xo-Xi); where Xo and Xi represent concentrations of molecules inside and outside the cell, P is the permeability constant

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7
Q

permeability coefficient for Fick’s law

A

based on 4 things 1.) partition coefficient 2.) diffusion coefficient 3.) membrane thickness 4.) area over which diffusion occurs

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8
Q

saturation kinetics and solute transport

A

facilitated diffusion or primary/secondary transport; shows saturation kinetics

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9
Q

active transport

A

uses energy either directly or indirectly from ATP to move molecules against their concentration gradient

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10
Q

antiport

A

molecules moving in opposite directions, ATP used indirectly

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11
Q

symport

A

molecules moving in same direction, ATP used indirectly

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12
Q

V class ATPase

A

in vesicles, stores chemicals in high concentration

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13
Q

P class ATPase

A

Na/K pump or Ca2+ transporter

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14
Q

F class ATPase

A

ATP synthases on inner mitochondrial membrane

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15
Q

Gut epithelial cell glucose transport mechanism

A

Na+/K+ ATP pump on blood/epithelial cell membrane keeps extracellular Na+ high, intracellular Na+ low. Glucose/Na+ symporter on lumen/epithelial cell membrane allows glucose to enter cell via secondary active transport because of low intracellular Na+ concentration. Glucose moves into blood via facilitated diffusion if concentration gradient permits.

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16
Q

pore (non-gated channel)

A

leakage channel, allow molecule to move through via simple diffusion, CREATE RESTING MEMBRANE POTENTIAL OF CELL!!!

17
Q

channel (gated pore)

A

gated by a door and responsible for action and synaptic potentials

18
Q

Na+/K+ pump

A

pumps 3 Na+ out of cell and 2 K+ into cell, against concentration gradients

19
Q

electrogenic

A

creates positive charge outside cell and negative charge inside cell (i.e. Na+/K- sodium pump)

20
Q

types of gated channels

A

voltage, ligand, mechanical, temperature, and water

21
Q

p-loop

A

where the ion binds loosely on a voltage gated ion channel, 5 transmembrane domain on voltage gated ion channels

22
Q

tetramer channels

A

Na+, Ca++ and K+ channels–4 subunits (each containing 6 transmembrane helices)

23
Q

components of a typical ion channel

A

1.) gate 2.) ion selectivity filter 3.) glycoproteins 4.) anchoring proteins 5.) voltage sensor or ligand binding site

24
Q

components of voltage-gated channels

A

6 domains of transmembrane helices, the 5th domains is known as the P loop at is the site for loose ion binding

25
membrane voltage
charge separation across membrane
26
partition constant
ratio of a molecule's solubility in oil to its solubility in water; high number is more lipophilic and results in a great ability to cross hydrophobic core of plasma membrane
27
carrier mediated transport
primary or secondary active transport
28
facilitated diffusion
pass transport through pore or channel; technically Vmax exists but concentration of ions in biological systems too high for Vmax to ever be reached; faster that passive transport at low ion concentrations
29
respiratory pump
H+ ions flow down concentration gradient, releasing energy to drive ATP production
30
ion channel selectivity
based on size and loose binding for specific ion
31
pentamer channels
nicotinic ACh receptor channel
32
hexamer channels
connexons that make up gap junction