Biochem Lipid Metabolism Flashcards
Long chain of carboxylic acid with ONE double bond
MONOunsaturated fatty acid
Long chain of carboxylic acid with no double bond
Saturated fatty acid
Long chain of carboxylic acid with TWO or MORE double bonds
POLYunsaturated Fatty Acid
Fatty acids associated with increased risk of atherosclerosis
Trans-fatty acids
Saturated fatty acids
Essential fatty acids
Linoleic acid - omega 6
Linolenic acid - omega 3
Linoleic acid - 2 double bonds/arachidonic acid/omega 6
Linolenic acid - 3 double bonds/18 carbons
Immediate precursor of prostaglandins
Arachidonic acid
- from Linoleic acid/Omega 6
End product of fatty acid synthesis
Palmitate
- 16 carbons without double bond
3 carbon compound that is a product of the oxidation of ODD numbered fatty acid
Propionyl CoA
- can be a precursor for Gluconeogenesis via succinyl CoA conversion
Enumerate the 3 ketone bodies
Acetoacetate
Beta butyrate
Acetone
kHetone bodieS: HMG CoA Synthase
Enumerate 3 organs that can use KETONES as a fuel source
Muscle
Renal cortex
Brain ( prolonged fasting > 2 weeks)
Give 2 primary bile acids
Cholic acid
Chenodeoxycholic acid
Give 2 molecules conjugated to bile acids to convert them into bile salts
Taurine
Glycine
Primary bile acids + taurine/glycine = bile salts
Give 2 secondary bile acids
Deoxycholic acid
Lithocholic acid
Clinical manifestation of lipid malabsorption
Steatorrhea
Fatty acid synthesis
What is it for? Where does it occur? What are the substrates? What are the products? Which step is rate limiting?
What is it for? Formation of palmitate (16:0)
Where does it occur?
Cytosol (liver, lactating mammary glands > adipose tissue)
What are the substrates?
1 acetyl CoA, 7 malonyl CoA (building block), NADPH and ATP
What are the products? Palmitate only
Which step is rate limiting? Acetyl CoA Carboxylase in
Acetyl CoA + ATP -> malonyl CoA
Synthesis of Triglycerides
Glycerol 3P + 3 fatty acyl CoA = triglyceride
Enzyme for lipolysis
aka hydrolyzes TAGs to yield free fatty acids and glycerol
Hormone sensitive lipase
Free fatty acid : bound to albumin in blood for Beta Oxidation
Glycerol : carbons backbone for Gluconeogenesis
Beta Oxidation of Fatty Acids
What is it for? Where does it occur? What are the substrates? What are the products? Which step is rate limiting?
What is it for?
Removal of acetyl CoA from ends of fatty acids
-Acetyl CoA enters TCA
- Generates NADH and FADH2 that also enter TCA
Where does it occur?
Mitochdria of all cells except neurons, RBC, testis, renal medulla.
Note that fatty acid activation occurs in cytosol.
What are the substrates?
Palmitate, NAD+, FAD, ATO
What are the products?
8 acetyl CoA, 7 NADH, 7 FADH2
Which step is rate limiting? Carnitine acetyl transferase
Fatty acyl CoA + carnitine –> fatty acyl carnitine + CoA
Ketogenesis
What is it for? Where does it occur? What are the substrates? What are the products? Which step is rate limiting?
What is it for? Convert acetyl CoA to ketone bodies
Where does it occur? Liver mitochondria
What are the substrates? Acetyl CoA
What are the products? Ketone bodies
- acetoacetate and beta hydroxybutyrate ( can be used as fuel)
- acetone ( not used as fuel)k
Which step is rate limiting? HMG CoA Synthase “kHetoneS”
Acetoacetyl CoA + acetyl CoA –> HMG CoA
Cholesterol synthesis
What is it for? Where does it occur? What are the substrates? What are the products? Which step is rate limiting?
What is it for? De novo synthesis of cholesterol
Where does it occur?
All cells : cytosol and SER ( mostly liver and intestines)
What are the substrates? Acetyl CoA, NADPH, ATP
What are the products? Lanosterol –> Cholesterol
Which step is rate limiting? HMG CoA Reductase
Steroid Hormone Synthesis
What is it for? Where does it occur? What are the substrates? What are the products? Which step is rate limiting?
What is it for? Steroid synthesis for GFR hormones
Where does it occur?
SER: adrenal cortex, ovaries, testes, placenta
What are the substrates? Cholesterol and Pregnenolone
Which step is rate limiting? Desmolase
Reaction: cholesterol –> Pregnenolone
Blocker: aminogluthetimide
Spherical macromolecular complexes composed of a neutral lipid core surrounded by a shell of amphipathic lipoproteins, phospholipid and nonesterified cholesterol
Lipoproteins
Protein moiety of lipoproteins
Apoprotein
Name that lipoprotein
Transport dietary triglyceride and cholesterol from intestine to tissues
Chylomicrons
