Short Answer Questions - Lipids and lipid metabolism
1. What is the structural difference between cis- and trans-fatty acids?
At a double bond in cis-fatty acids hydrogen atoms are on the same side of the double bond, compared with trans-fatty acids where the hydrogen atoms are on opposite sides of the double bond
2. If phosphatidic acid is the group common to the phospholipids, what is the equivalent group common to the sphingolipids?
Ceramide.
3. Which is the largest and which is the smallest of the lipoprotein family?
The largest is a chylomicron; the smallest is a high density lipoprotein (HDL).
4. Which enzyme regulates de novo cholesterol synthesis? Name the class of drugs which competitively inhibit this enzyme.
The enzyme is hydroxymethylglutaryl CoA (HMGCoA) reductase, and it is competitively inhibited by statins.
5. Following de novo biosynthesis of cholesterol in the liver, which lipoprotein transports it to the periphery?
Very low density lipoprotein (VLDL).
6. Which lipoprotein removes surplus cholesterol from the periphery and transports it to the liver for disposal?
High density lipoprotein (HDL).
7. Which lipoprotein transports dietary fat (triacylglycerols) and dietary cholesterol from the intestine?
Chylomicron.
8. Cholesterol is the precursor of four types of steroid hormone: what are their names?
Aldosterone (mineralocorticoid), cortisol (glucocorticoid), testosterone, dihydrotestosterone (androgens, anabolic steroids), and oestradiol (oestrogen).
