D4H1 Cholesterol & Derivatives

Question 1

deficient enzyme in Von Gierke disease (type I)

Answer 1

Glucose-6-phosphatase

Question 2

deficient enzyme in Cori disease (type III)

Answer 2

debranching enzyme (alpha-1,6-glucosidase)

Question 3

Glycogen storage diseases (4 diseases)

Answer 3

“Very Poor Carbohydrate Metabolism”

• Von Gierke disease
• Pompe disease
• Cori disease
• McArdle disease

Question 4

consequences of glycogen storage diseases

Answer 4

result in abnormal glycogen metabolism and accumulation of glycogen within cells

Question 5

causes/consequences of lysosomal storage diseases

Answer 5

• each caused by a deficiency in one of the many lysosomal enzymes
• results in an accumulation of abnormal metabolic products

Question 6

functions of cholesterol

Answer 6

1) major constituent of cell membranes
2) is the biosynthetic precursor of bile acids, which are essential for fat digestion
3) is the precursor of all steroid hormones (androgens, estrogens, progestins, vitamin D, etc)

Question 7

processes that determine the cholesterol balance

Answer 7

• intestinal update of dietary cholesterol
• de novo cholesterol synthesis
• synthesis of steroid hormones from cholesterol
• synthesis of bile acids from cholesterol, and their biliary secretion
• biliary secretion of surplus cholesterol in unmodified form

Question 8

8 major stages of cholesterol synthesis

Answer 8

acetyl-coA –>–> HMG-CoA –> mevalonate –> activated C5 –> activated C10 –> activated C15 –> squalene (linear C30) –> lanosterol –>–> cholesterol