Membrane Transporters (Wright) Flashcards Preview

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Flashcards in Membrane Transporters (Wright) Deck (7):
1

Three types of facilitated transport

1) Uniporter (GLUT1)

2) Co-transporter/Symporter (Na/glucose SLC5A1)

3) Exchanger (Cl/HCO3 SLC4A3)

 

 

2


Three classes of membrane transporters


1) Channels (Aquaporins)

2) Carriers

3) Pumps (Na/K; H/K)

3


GLUT1, 2, 3, 4 locations


GLUT1 = BBB

GLUT2 = liver, intestine, kidney

GLUT3 = neurons

GLUT4 = muscle, fat

4


Transcellular


Ion or molecule enters cell through plasma membrane, diffuses through cell, and exits on the other side

5

Paracellular


Ion or molecule passes between cells through tight junctions

6


"Leaky epithelia"


The tight junctions in leaky epithelia allow some ions to go through (but can be selective about which ones)

Note: water does NOT use paracellular pathway, it uses transcellular and aquaporins

7


How is ATP generated in the mitochondria?

ATP synthetase/F0F1/ComplexV of electron transport chain

1) Complexes I, III, IV of electron transport chain generate H+ gradient from NADH and FADH2 from citric acid cycle

2) F0 subunit: H+ goes into one C subunit then hops 12 times, turning protein (including F1 alpha and beta subunits)

3) ATP binds to alpha/beta site and P+ADP binds to another empty site

4) Rotation of protein causes ADP+P to turn into ATP and causes initial ATP to come off into mitochondrial matrix