UNIT 1:Lipids

What is the optimal level of triglycerides?

less than 150 mg/dL

What is the optimal level of HDL-C in males?

greater than 40 mg/dL

What is the optimal level of HDL-C in females?

greater than 50 mg/dL

What level of Total Cholesterol is deemed normal?

less than 200 mg/dL

What level of LDL-C is deemed normal?

less than 100 mg/dL

Which lipid lowering drugs lower triglycerides and raise HDL?

fenofibrate, gemfibrozil

Which lipid lowering drug lowers LDL and raises HDL?

Niacin (vitamin B3)

Which energy sources satisfy short term energy needs?

glucose, glycogen

Which energy sources satisfy long term energy needs?

fats

Why are fatty acids better energy sources?

carry more Energy per carbon

Which lipids are used for storage?

triacylglycerols

Which lipid types are essential for membranes?

phospholipids, glycolipids, sterols

What is the characteristic feature of a sterol?

4 fused rings

What are the components of a glycerophospholipid?

glycerol backbone, 2 FA, phosphate group

What are the membrane phospholipids?

glycerophospholipid, sphingolipid

What is the composition of a glycolipid?

sphingosine backbone, FA, sugar

What type of fatty acid's are typically solids at room temp?

saturated

Which type of fatty acid's are typically liquids at room temp?

unsaturated

Individuals with hypertriglyceridemia have triglyceride levels of...

greater than or equal to 500 mg/dL

What drug is given to individuals with a triglyceride level of 500 mg/dL or greater?

Lovaza

What type of fat is formed by partial hydrogenation of alternating double bonds?

trans fat

Where are triacylglycerols stored at?

adipocytes

Which FA are considered unhealthy?

Saturated

What are the 2 essential poly fatty acids?

omega 3 omega 6

Which semi-essential FA are derived from omega 3?

EPA, DHA

What does EPA stand for?

eicosapentaenoic acid

What does DHA stand for?

docosahexaenoic acid

Which semi-essential FA are derived from omega 6?

AA, DGLA

What does AA stand for ?

arachidonic acid

What is Lovaza used to treat?

Hypertriglyceridemia

What levels of triglycerides result in hypertriglyceridemia?

greater than/equal to 500 mg/dL

Lovaza is essentially?

ethyl ester of EPA/DHA

What causes Barth Syndrome?

mutations in Cardiolipin synthesis cause dysfunctional mitochondrial membranes

What type of membrane lipid is associated with barth syndrome?

glycerophospholipid

What causes Niemann-Pick syndrome?

accumulation of sphingomyelin in brain, spleen, liver

What are the 3 main fuel sources?

FA, carbs, protein

Why is it necessary for TAG to be emulsified by bile salts in small intestine?

smaller lipid droplets allow for digestion by lipases

What is the role of intestinal lipases?

convert TAG to 2FA and monoacylglycerol for intestinal absorption

What does Xenical (orlistat) act upon?

inhibits lipases

What occurs when a FA enters myocytes?

oxidized for ATP production

What occurs when a FA enters adipocytes?

reesterified for storage

What do Lipoprotein Lipases in the capillaries do?

convert TAG to fatty acids and glycerols

What is the relationship between protein weight and TAG weight for lipoproteins?

increased protein = decreased TAG

What is the %wt of protein in LDL?

23

What is the %wt of protein in HDL?

55

Which lipoprotein carries fats/cholesterol from the bloodstream to the tissues?

chylomicrons

Which lipoprotein has the greatest amount of TAG?

chylomicrons

What 3 apolipoproteins are present on the surface of a chylomicron?

ApoB-48, ApoE, and ApoCii

What apolipoprotein on the surface of LDL allows for LDL receptor binding?

ApoB-100

What apolipoprotein is assosciated with VLDL and LDL?

ApoB-100

What apolipoprotein's are assosciated with chylomicrons, VLDL, and HDL?

ApoC-ii , ApoC-iii

What is the function of ApoC-II?

activates lipoprotein lipase

What is the function of ApoC-III?

inhibits lipoprotein lipase

A mutation in ApoB-100 results in what condition?

hypercholesterolemia

A mutation in the gene for ApoC-II results in what condition?

hyperlipoproteinemia

What is the function of HDL?

bring excess cholesterol from the cells back to the liver

What enzyme is present on the surface of HDl?

Lechitin-cholesterol acyl transferase (LCAT)

What reaction is catalyzed by LCAT?

formation of C-esters

What range (numerically) of LDL levels contributes to atherosclerosis?

160 to 189 mg/dL

What causes LDL's to stick to the lining of arteries?

partly oxidized fatty acyl groups

What is the role of macrophages in LDL promotion of cardiovascular disease?

attracted to LDL accumulation in arteries and consume Cholesterol/C-esters

What is the result of macrophage accumulation of cholesterol?

FOAM Cells = undergo apoptosis

What is the direct cause of a heart attack or stroke?

occluded blood vessels

Where does FA synthesis occur?

liver, adipose

What is the precursor to Acetyl-CoA?

pyruvate

What is the key intermediate(precursor) for FA synthesis?

Malonyl CoA

What does the conversion of Acetyl-CoA to Malonyl-CoA require?

Biotin (B7)

What is the key intermediate (precursor) for synthesis of both Ketones and Cholesterol?

HMG-CoA

Where does ketone production occur (inside of cell)?

mitochondria

Where does cholesterol production occur (inside of cell)?

cytosol

What intermediate is formed from HMG-CoA Reductase?

mevalonate

What is the rate-limiting enzyme in cholesterol synthesis?

HMG-CoA Reductase

What regulation does HMG-CoA reductase experience?

feedback inhibition by cholesterol and mevalonate

What occurs in step 1 of free fatty acid oxidation?

conversion of FA to fatty acyl CoA derivatives

What is the intermediate product in step 1 of oxidation of free FA?

fatty acyl adenylate

What occurs in step 2 of free fatty acid oxidation?

conversion of fatty acyl CoA to acylcarnitine

What is the key enzyme for step 2 of free fatty acid oxidation?

Carnitine acyltransferase I

What is the importance of step 2?

entry into mitochondria

What occurs in step 3 of free fatty acid oxidation?

Beta Oxidation

What is Beta Oxidation?

successive oxidative removal of 2 carbon fragments

What are the 3 direct products of 1 round of Beta Oxidation (2 carbons)?

acetyl CoA, FADH2, NADH

What is the key enzyme of Beta Oxidation?

Acyl-CoA Dehydrogenase

What are the 6 common features of Acyl-CoA Dehydrogenase deficiency?

- fat accumulation in the liver

- high octanoic acid levels in the blood

- hypoglycemia

- sleepiness

- vomit

- coma

What situations promote an increase in ketone bodies?

uncontrolled diabetes, starvation

The conversion of acetyl-coA to ketone bodies allows for...

free CoA allows Beta oxidation to continue

Where does the liver release ketone bodies?

into bloodstream

Which 2 ketone bodies contribute to acidosis?

acetoacetate, B-hydroxybutyrate

What are the 3 ketone bodies?

acetoacetate, B-hydroxybutyrate, acetone