Biochem - Lipid and Cholesterol Flashcards

1
Q

Chylomicrons

A

Deliver TGs to peripheral tissue

Deliver cholesterol to liver

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2
Q

VLDL

A

TG to peripheral tissues – secreted by liver

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3
Q

IDL

A

By product formed in degradation of VLDL

Deliver TG and cholesterol to liver

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4
Q

ApoB48

A

Chylomicron secretion from enterocyte to lymphatic system

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5
Q

ApoB100

A

Found in VLDL, IDL, LDL

Need to leave the liver into circulation

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6
Q

ApoE

A

Mediates Extra remnant uptake

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7
Q

ApoA1

A

Activates LCAT

Found on HDL

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8
Q

Apo CII

A

Cofactor for lipoprotein lipase

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9
Q

Abetalipoproteinemia

A

AR
Decreased ApoB48 and ApoB100 – chylomicrons can’t leave enterocyte
Mutation MTP gene (microsomal transfer protein)
-> chylomicron and VLDL synthesis and secretion

Steatorrhea: can’t absorb ADEK and fats

Intestinal bx: enterocytes swollen w/ TGs
Peripheral smear: acanthocytosis of RBCs – spikey

Ataxia – vit E
Night blindess – vit A

Tx: vit E helps restore lipoproteins

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10
Q

Draw out lipid transport pathway

A

Page 553

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11
Q

Draw out HDL transport

A

Page 553

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12
Q

Type I hyperchylomicronemia

A

AR
Lipoprotein lipase deficiency or defective ApoCII

Increased chylomicrons, TGs, cholesterol

Present:
Pancreatitis d/t high TGs
HSM
Pruritic xanthomas

No increased risk for atherosclerosis

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13
Q

Type IIa Familial hypercholesterolemia

A

AD
Absent or low LDL receptors – uptake LDL from blood

Tendinous xanthomas
Corneal arcus
Accelerated atherosclerosis
Homozygous -> MI as young as 20s

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14
Q

Type IV hypertriglyceridemia

A

AD
High VLDL, high TGs
Overproduction of VLDL in liver
High TG -> pancreatitis

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15
Q

Signs of hypercholesterolemia

A

Atheroma – oxidized LDL particles, plaque in BV wall

Xanthoma – nodules of histiocytes filled w/ cholesterol
-eyelids – xanthalasma

Tendinous xanthomas – Achilles

Corneal arcus – white ring around iris

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16
Q

Cholesterol synthesis

A

Acetyl-CoA substrate
Rate limiting enzyme – HMG-CoA reductase
-blocked by statins

17
Q

Fatty acid synthesis

A

Precursor acetyl CoA
Cytoplasm of hepatocytes

Rate limiting enzyme: Acetyl-CoA carboxylase

18
Q

Fatty acid degradation

A

Mitochondria matrix

  • b-oxidation of acetyl CoA into groups
  • > ketone body buildup or TCA

Rate limiting enzyme: Carnithine acyltransferase (CAT1) aka Carnitine palmitoyl transferase 1

19
Q

Carnitine deficiency

A

Unable to transfer LCFAs to mt
Accumulation of LCFAs in cytoplasm
-> weakness, hypotonia, hypoketotic hypoglycemia