FURCI EXAM 3

Question 1

Complex lipids are comprised of ____, _____, and ____….and are typically found in two locations: _____ and ______

Answer 1

Complex lipids are comprised of Glycerophospholipids, Sphingolipids, and Cholesterol….and are typically found in two locations: Biological Membranes and Circulating Lipoproteins

Question 2

• Triglycerides (triacylglycerol) Synthesis
• Glycerophospolipids
o Synthesized in the liver and in adipose tissue from _______
o Precursors: _______ and ______
o Liver –______ → glycerol 3-P
o Adipose tissue –_________ → glycerol 3-P
o ______ is the primary starting material for phosphatidic acid

Answer 2

• Triglycerides (triacylglycerol) Synthesis
• Glycerophospolipids
o Synthesized in the liver and in adipose tissue from GLYCEROL-3-P
o Precursors: Phosphatidic Acid and DAG
o Liver –Glycerol→ glycerol 3-P
o Adipose tissue –DHAP→ glycerol 3-P
o Glycerol-3-P is the primary starting material for phosphatidic acid

Question 3

• Cardiolipin (DPG)
  -A second ______ acid may be
  added to _____ to form DAG
  -First major class of ______
  -Represents ~___% of phospholipids in heart mitochondria (where it is almost exclusively found)

Answer 3

• Cardiolipin (DPG)
  - A second Phosphatidic acid may be added to Phosphatidylglycerol to form DAG
  - First major class of Mitochondrial Lipids
  - Represents ~20% of phospholipids in heart mitochondria (where it is almost exclusively found)

Question 4

• Glycoshingolipids are classified into 3 groups:

1. _______ (contain only neutral and amino sugars; found in animal cells)
2. _________ (sulfide-containing; found in CNS)
3. __________ (Sialic acid (NANA); Found in Autoimmune)

Answer 4

• Glycoshingolipids are classified into 3 groups:

1. CEREBROSIDES (contain only neutral and amino sugars; found in animal cells)
2. SULFATIDES (sulfide-containing; found in CNS)
3. GANGLIOSIDES (Sialic acid (NANA); Found in Autoimmune)

Question 5

Cholesterol is the essential component of mammalian cell membranes and the precursor of ____, ____, and _____.

Answer 5

Cholesterol is the essential component of mammalian cell membranes and the precursor of Bile Acids, Steroid Hormones, and Vitamin D.

Question 6

o _________ specifically mediates cellular uptake of intact LDL
• Expression of apo B/E regulated by _______

Answer 6

LDL (apoB/E) Receptor specifically mediates cellular uptake of intact LDL
• Expression of apo B/E regulated by INTRACELLULAR CHOLESTEROL CONCENTRATION

Question 7

• Increase in intracellular cholesterol concentration:
• _______ in activity and expression of HMG-CoA reductase, decreasing cholesterol synthesis
• _________ of LDL receptors, limiting further cellular entry of cholesterol
• _______ in cholesterol and phospholipid efflux from cell to apoproteins
• ______ in rate of conversion to bile acids and excretion

Answer 7

• Increase in intracellular cholesterol concentration:
• DECREASES in activity and expression of HMG-CoA reductase, decreasing cholesterol synthesis
• DOWNREGULARION of LDL receptors, limiting further cellular entry of cholesterol
• INCREASES in cholesterol and phospholipid efflux from cell to apoproteins
• INCREASES in rate of conversion to bile acids and excretion

Question 8

o De novo synthesis

• Three molecules of acetyl-CoA are converted into 6-carbon _______

Answer 8

o De novo synthesis

• Three molecules of acetyl-CoA are converted into 6-carbon

Question 9

• Rate-limiting reaction:
• Irreversible formation of mevalonate
• Catalyzed by _______

Answer 9

• Rate-limiting reaction:
• Irreversible formation of mevalonate
• Catalyzed by HMG-CoA

Question 10

o Primary bile acids (_____ and ________)

• Rate-limiting _________

Answer 10

isomerization of the cholesterol 3β-hydroxyl group
o Primary bile acids (CHOLIC and CHENODEOXYCHOLIC)
• Rate-limiting 7-alpha-HYDROXYLASE ENZYME (CYP7A1)

Question 11

o Secondary bile acids form in _______ through the action of _______

Answer 11

o Secondary bile acids form in INTESTINES through the action of BACTERIOSIDES BACTERIA

Question 12

• Steroid Hormones
o Cholesterol precursor to all
o Three groups:
• _________: 21 carbon atoms with basic pregnane ring structure
• _________: 19 carbon atoms with androstane ring
• ________: Loss of methyl group at carbon atom 19 (aromatization of A
ring) produces estrane structure

Answer 12

• Steroid Hormones
o Cholesterol precursor to all
o Three groups:
• CORTICOSTEROIDS: 21 carbon atoms with basic pregnane ring structure
• ANDROGENS : 19 carbon atoms with androstane ring
• ESTROGENS: Loss of methyl group at carbon atom 19 (aromatization of A ring) produces estrane structure

Question 13

o Synthesis occurs in only three organs:
• ________ –corticosteroids
• _________ – androgens
• _______ - estrogens

Answer 13

o Synthesis occurs in only three organs:
• ADRENAL CORTEX –corticosteroids
• TESTES IN MEN – androgens
• OVARIES IN WOMEN- estrogens