005 Ion Flex Through Membranes

Question 1

the major types of membrane transport

Answer 1

passive transport
active transport (primary and secondary)

Question 2

what is the concentration gradient of calcium between extracellular and intracellular

Answer 2

the calcium is concentrated 10,000x more extracellularily

Question 3

the energy independent movement of molecules down a gradient that is unaided

Answer 3

simple diffusion
(molecules that are small, non polar, and uncharged polar diffuse freely across)

Question 4

the energy independent movement of molecules down a gradient with the assistance of a transmembrane protein

Answer 4

facilitated diffusion
(molecules that are large and charged unable to cross the membrane)

Question 5

transports one substance in one direction (downhill)

Answer 5

uniporter

Question 6

general term for something that transports two different substances

Answer 6

cotransporter

Question 7

a cotransporter that transports in the same direction

Answer 7

symporter

Question 8

a cotransporter that transports in opposite directions

Answer 8

antiporter

Question 9

cystinuria

Answer 9

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)

Question 10

hartnup disease

Answer 10

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

Question 11

types of ligands that can bind

Answer 11

neurotransmitter or hormone

Question 12

how steve irwin died

Answer 12

stringray stung him with tetrodotoxin to the heart and it inhibited the sodium channels which prevented neurotransmission and his heart stopped beating

Question 13

in primary active transport, ATP hydrolysis induces this

Answer 13

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)

Question 14

inhibitors of Na+/K+ ATPase

Answer 14

Ouabain and Digoxin

used to treat congestive heart failure

Question 15

there is no ATP hydrolysis in

Answer 15

secondary active transport

Question 16

sodium glucose transporter 1 (SGLT1)

Answer 16

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

Question 17

Na+ Ca2+ exchanger (NCX)

Answer 17

antiporter
to maintain low levels of intracellular calcium in cells
3Na down gradient and 1 Ca against gradient

Question 18

uptake of dietary monosaccharides

Answer 18

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

Question 19

D glucose and D galactose secondary active transport into intestinal epithelial cells by

Answer 19

SGLT1

Question 20

D glucose and D galactose transported across enterocyte into blood stream by facilitated diffusion via

Answer 20

GLUT2

Question 21

fructose facilitated diffusion

Answer 21

apical side- GLUT5

basal side- GLUT2

Question 22

Na+ transported primary active transport

Answer 22

SGLT1 mediated by Na+/K+ ATPase basolateral

Question 23

cardiotonic drugs (contraction inducing)

Answer 23

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

Question 24

cystic fibrosis

Answer 24

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