Ion Flux

Question 1

Which molecules can travel by way of simple diffusion?

Answer 1

Small nonpolar and and uncharged polar

Question 2

Facilitated diffusion is needed by who?

Answer 2

large and in charge need proteins to function as transporters
water, Na, Cl, K , gluc

Question 3

What is the structure of a channel?

Answer 3

polar tube to allow latge charged molecules through

Question 4

How do transporters work?

Answer 4

bind to molecule on one side change conformation and spit them out on the other side

Question 5

Cystinuria is what?

Think CALO

Answer 5

autosomal recessive disease which causes a defect in the channels responsible for transporting cystine arginine, lysine, and ornathine

Question 6

What pathology happens in Cystinuria?

Answer 6

too much CALO so cystine crystals form in the kidney tubules and become stones patients present with renal colic

Question 7

Hartnup disease

Answer 7

autosomal recessive disorder where transporters for nonpolar or neutral amino acids like trp is defective (found primarily in kidney and intestines

Question 8

S/S of Hartnup disease

Answer 8

Failure to thrive, nystagimus, tremors, ataxia because aa balance is off

Question 9

2 kinds of gated ion channels

Answer 9

Ligand and voltage gated ion channels

Question 10

What is primary active transport?

Answer 10

protein assisted movement of something across a membrane up its concentration gradient using ATP hydrolysis

Question 11

2 Examples of primary active transport

Answer 11

Na/K (3NA our and 2 K in) atpase pump and Ca++ atpase punp

Question 12

2 inhibitors of Na/K atpase pump

Answer 12

Ouabain and digoxin, in people having a cardiac episode these drugs are given to inhibit the pump and increase intracellular Ca++ to increase contracton

Question 13

What is secondary active transport?

Answer 13

NO ATP is used here. It’s just coupling energy of moving something down a graadient with moving something else up a gradient

Question 14

2 examples of secondary active transport

Answer 14

Na/Glucose transporter

Na linked Ca++ antiporter (linked with Na/Ca++ exchanger)

Question 15

Where is the sodium glucose transporter?

Answer 15

SGLT1 is present in epithelial cells that line the small intestine and renal tubule

Question 16

What does SGLT1 do?

Answer 16

mediated the unidirectional movement of Na and glucose across the membrane, Na goes down its gradient and gluc goes up

Question 17

What other transporter allows the SGLT system to work?

Answer 17

Na/K atpase pump which resets the sodium balance by pumping Na back out into the intestinal lumen

Question 18

What is the NA/Ca++ exchanger (NCX)

Answer 18

its an antiporter that functions to maintain low levels of intracellular Ca++ (3Na in and 1 Ca++ out) maintained by Na/K pump

Question 19

how are monosaccharies (from polysaccharides from food) carried across the enterocyte lumen of the intestines?

Answer 19

facilitated diffusion and active transport