005 Ion Flex Through Membranes Flashcards
the major types of membrane transport
passive transport active transport (primary and secondary)
what is the concentration gradient of calcium between extracellular and intracellular
the calcium is concentrated 10,000x more extracellularily
the energy independent movement of molecules down a gradient that is unaided
simple diffusion (molecules that are small, non polar, and uncharged polar diffuse freely across)
the energy independent movement of molecules down a gradient with the assistance of a transmembrane protein
facilitated diffusion (molecules that are large and charged unable to cross the membrane)
transports one substance in one direction (downhill)
uniporter
general term for something that transports two different substances
cotransporter
a cotransporter that transports in the same direction
symporter
a cotransporter that transports in opposite directions
antiporter
cystinuria
autosomal recessive defect in transport system for the uptake of dimeric amino acid cysteine and dibasic amino acids arginine, lysine and ornithine
results in formation of cysteine crystals or stones in kidney (renal calculi) identified via positive nitroprusside test
present with renal cholic (abdominal pain that comes in waves and linked to kidney stones)
hartnup disease
autosomal recessive defect in transporter for non polar or neutral AA like tryptophan
kidneys and intestine
infancy failure to thrive, nystagmus, intermittent ataxia, tremor and photosensitivity
types of ligands that can bind
neurotransmitter or hormone
how steve irwin died
stringray stung him with tetrodotoxin to the heart and it inhibited the sodium channels which prevented neurotransmission and his heart stopped beating
in primary active transport, ATP hydrolysis induces this
a conformational change in the transporter that allows the molecule to be released on the other side of the membrane
(Na+/K+ ATPase and Ca2+ ATPase)
inhibitors of Na+/K+ ATPase
Ouabain and Digoxin
used to treat congestive heart failure
there is no ATP hydrolysis in
secondary active transport
sodium glucose transporter 1 (SGLT1)
mediates the unidirectional movement of Na+ and glucose
Na+ goes down its gradient and glucose up its gradient
Na+ gradient reset by Na+/K+ ATPase
type of symporter
Na+ Ca2+ exchanger (NCX)
antiporter
to maintain low levels of intracellular calcium in cells
3Na down gradient and 1 Ca against gradient
uptake of dietary monosaccharides
monosaccharides digested from disaccharides and polysaccharides need to be transported from intestinal lumen across enterocyte into blood stream
facilitated by facilitated diffusion and active transport
D glucose and D galactose secondary active transport into intestinal epithelial cells by
SGLT1
D glucose and D galactose transported across enterocyte into blood stream by facilitated diffusion via
GLUT2
fructose facilitated diffusion
apical side- GLUT5
basal side- GLUT2
Na+ transported primary active transport
SGLT1 mediated by Na+/K+ ATPase basolateral
cardiotonic drugs (contraction inducing)
cardiac glycosides such as ouabain and digoxin
inhibit the Na+/K+ ATPase on cardiac myocytes
leads to increase in Ca2+ due to slowing of NCX
increased sarcoplasmic Ca2+ results in stronger excitation contraction of heart muscle with each action potential
cystic fibrosis
autosomal recessive thick mucous secretions in lungs interfere with breathing and lead to secondary microbial infections
mutation in CF transmembrane conductance regulator (CFTR) gene. defective CFTR protein
defective CFTR causes buildup of Cl and Na in airways and sweat
