S14 Cardiac biochemistry

Question 1

bile acid sequestrants

Answer 1

cholestyramine resins

Question 2

cholestramine resin function

Answer 2

inhibit uptake of cholesterol by capturing cholesterol to associate with non-digestible fiber

Question 3

stanol esters

Answer 3

inhibit uptake of cholesterol by displacing cholesterol from bile containing micelles in the GI tract

Question 4

Ezetamibe

Answer 4

inhibits uptake of cholesterol in the small intestine by affecting transport by gastrointestinal epithelial cells

Question 5

Smith-lemli-opitz syndrome

Answer 5

inherited deficiency of Δ7-sterol reductase (catalyzes last step in cholesterol synthesis)

most common disorder of sterol synthesis

diagnosed by plasma sterol analysis

7-dehydrocholesterol (enzyme substrate accumulates; immediate Vitamin D precursor)

variable clinical presentations

facial feature problems
syndactyly of second and third toe

Question 6

bile salts are biosynthesized from substrate cholesterol in what pathways which produce what

Answer 6

short oxidation pathways which produce chenodeoxycholic acid and chalice acid

Question 7

rate limiting step in bile salt synthesis

Answer 7

7-alpha hydroxylase. modifies 7 position by oxidation in rate limiting step by cytochrome P45- enzyme.

subject to product feedback by bile acids.

Question 8

bile acids are modified by conjugation with

Answer 8

glycine and taurine.

made by bacteria in intestines prior to reabsorption by enterohepatic circulation