Biochemistry-Steroids Flashcards
Where does cholesterol synthesis take place?
liver and intestines
Where in the cell does cholesterol synthesis take place?
cytoplasm
What is the precursor for cholesterol synthesis?
Acetyl-CoA
What pathway is the greatest producer of Acetyl-CoA?
beta-oxidation
What is the regulatory enzyme of cholesterol synthesis?
HMG-CoA reductase
What hormone promotes the action of HMG-CoA reductase?
Insulin
What are 2 significant intermediates in cholesterol synthesis?
HMG-CoS, mevalonate, squalene, desmuterol
What is the function of cholesterol?
membran fluidity, precursor to all steroid hormones
What type of fatty acid increases cholesterol? What type of fatty acid decreases cholesterol?
Increases: saturated fats
Decreases: unsaturated fats
What other metabolite is formed from mevalonate?
CoQ10
What 2 substances act as conjugating agents to convert bile acids into bile salts?
Taurine, Glycine
What enzyme is involved in bile acid production?
7-alpha hydroxylase
What vitamin is needed for the activity of 7-alpha hydroxylase?
Vitamin C
What are the 2 primary bile acids?
Cholyl-CoA
Chenodeoxychoyl-CoA
What the 2 secondary bile acids?
Deoxycholic acid
lithocholic acid
Where are bile acids formed?
Liver and intestines
Where are bile acids stored?
gallbladder
Where does bile acid reabsorption take place?
ileum
What are 2 functions of bile acids?
Fat emulsification
Cholesterol excretion
Testosterone is produced in which tissue?
Adrenal cortex
Estrone and estradiol are produced in which tissue?
Ovaries and a small amount in the adrenal cortex
DHEA, progesterone, cortisol and aldosterone are produced in which tissue?
adrenal cortex
What is the precursor for steroid hormones?
cholesterol
What vitamin is needed for steroid hormone production?
Vitamin C
