9 - Lipids 3 Flashcards
Why is cholesterol synthesis important? Where is synthesized and how much?
- In humans, approximately 1g is daily synthesized
- After intestinal absorption
-Chylomicrons (Liver and peripheral tissues) - After Biosynthesis
-VLDL (Peripheral tissues)
-LDL (Peripheral tissues) - HDL (Removal from circulation)
- Cholesterol sterol structure is not metabolized by
humans.
-incorporated into bile salts
What is the clinical relevance of cholesterol synthesis and reuptake?
How is cholesterol synthesized?
All tissues have the capacity of synthesizing cholesterol. Liver is the main site of synthesis
What is needed for synthesizing cholesterol:
* Acetyl-CoA (β-oxidation, dehydrogenation of pyruvate)
* NADPH (reducing agent)
* ATP
For every 1 mole of cholesterol:
* 18 moles of acetyl-CoA
* 16 moles of NADPH
* 36 moles of ATP
Stage 1: Synthesis of Mevalonate (six carbons) from Acetyl CoA
Stage 2: Conversion of Mevalonate to Farnesyl pyrophosphate (15 carbons) Stage 3: Condensation of 2 moles of Farnesyl pyrophosphate to Squalene (30 carbons)
Stage 4: Conversion of Squalene to cholesterol (27 carbons)
How is cholesterol synthesis regulated?
How is cholesterol incorporated into bile? How is that process regulated?
What is the clinical relevance of cholesterol and bile?
How can cholesterol levels be lowered?
Why is cholesterol important in the endocrine system?
What is the clinical relevance of cholesterol’s role in steroid hormones?
What do lipoproteins do?
What are apolipoproteins? How many are there and what does each class do?
What enzymes are associated with lipoprotein function?
What is the function of HDL? Explain its mechanism of action and possible fates.
What is Atherosclerosis and how does it come about?
What are the dyslipidemias and what dysfunction is associated with each?
How are dyslipidemias treated?
