Term
| What are the six major LP's and what are their functions? |
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Definition
| 1) Chylomicrons (fat from intestines to organs), 2) Chylomicron remnants (fat-some TG but mostly CE-to liver), 3) VLDL (TG from liver to other tissues), 4) IDL, 5) LDL (CE transport), 6) HDL (Removal of excess chol from tissues and LP's; LP remodeling) |
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Term
| Rank the LP's based on percentage of TG (highest to lowest). |
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Definition
| Chylomicrons, VLDL, IDL, LDL, HDL |
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Term
| Rank the LP's based on percentage of protein (highest to lowest). |
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Definition
| HDL, LDL, IDL, VLDL, Chylomicrons |
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Term
| Rank the LP's based on percentage of total cholesterol (highest to lowest). |
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Definition
| LDL, IDL, VLDL, HDL, Chylomicrons |
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Term
| Where are CE and TG located in LP's? |
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Definition
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Term
| What is the lifetime of LDL? |
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Definition
| It's long-about three days. |
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Term
| Rank the LP's based on electrophoretic mobility (least to most). |
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Definition
| Chylomicrons (immobile), LDL (B), IDL & VLDL (pre-B, broad-B), HDL2 (A), HDL3 (A) |
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Term
| Outline forward transport. |
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Definition
| Dietary lipids in the intestine move to chylomicrons. Delivery of fats to the tissues (loss of ApoC) and chylomicron remnants are taken up by liver (ApoE, ApoB48). VLDL is produced by the liver and delivers TG's to tissues (loss of ApoC). IDL results which can get taken up by liver (reverse by ApoE) or turn into LDL. LDL transports CE's and eventually gets taken up by the liver (reverse by ApoB100) or by peripheral tissues (reverse LDLR). |
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Term
| Outline reverse transport (HDL's role). |
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Definition
| The liver makes nascent HDL which picks up CE's by way of LCAT and PLPT. HDL gives CE's to LP's in exchange for TG and takes their ApoC's so that binding via ApoE/ApoB is facilitated. HDL can be taken up by the liver via SRB1 (forward). |
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Term
| What Apoproteins stay bound throughout the life cycle of a LP? |
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Definition
| ApoB's (48 on Chylomicron and 100 on VLDL, IDL, LDL) |
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Term
| Why is it that apolipoproteins can exchange so easily between LP's? |
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Definition
| They have significant water solubility. |
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Term
| True or false: In reverse transport, HDL transfers C to TG-rich LP's. |
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Definition
| False. This happens in forward transport. |
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Term
| What is the role of ApoC1? |
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Definition
| It inhibits CETP (i.e. HDL doesn't readily exchange with VLDL, IDL, or chylomicron remnants.) |
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Term
| What is the role of ApoC2? |
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Definition
| It activates LPL (i.e. VLDL and IDL drop TG's.) |
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Term
| What is the role of ApoC3? |
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Definition
| It inhibits VLDL lipolysis. |
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Term
| Mutations in the ApoC genes lead to what? |
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Definition
| Familial chylomicronemia and hyperlipidemia. |
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Term
| True or false: Chylomicrons aquire ApoC's and E's from HDL |
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Definition
| True. After they drop TG's, the ApoC's go back to HDL and the chylomicron remnant binds to the liver via ApoE-R. |
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Term
| Why does LDL have a long half-life? |
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Definition
| ApoB100 binds with a much lower affinity than ApoE (which it lost upon conversion from IDL). |
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Term
| When does nascent HDL turn into discoidal HDL? |
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Definition
| Nascent HDL starts as very lipid poor. It picks up cholesterol and PL via ABCA1 on peripheral cells. |
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Term
| When does discoidal HDL turn into spheroidal HDL? |
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Definition
| Discoidal HDL picks up free cholesterol and certain Apo's from serum LP's and becomes spheroidal. |
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Term
| What is SRB1 also known as (what is its role?)? |
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Definition
| It's known as scavenger receptor B1 since it takes up CE's from HDL. |
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Term
| What's bigger: HDL2 or HDL3? |
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Definition
| HDL 2 is bigger. HDL3 is denser and moves faster in electrophoresis. |
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Term
| Name something that induces LPL activity. |
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Definition
| Insulin comes to mind. With homozygous mutations in LPL, you can't store fat and thus see hypertrigyceridemia. |
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Term
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Definition
| PLTP stands for phospholipids transfer protein. It transfers PL's to HDL. |
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Term
| True or false: Heptac lipase is similar to LPL. |
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Definition
| True. It plays an important role in conversion of VLDL to HDL. |
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Term
| True or false: ACAT is responsible for the synthesis of virtually all CE in plasma LP's. |
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Definition
| False. LCAT operates in the plasma. |
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Term
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Definition
| LDL, VLDL remnants, IDL (ApoE, B100) |
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Term
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Definition
| Chylomicron remnants (ApoE) |
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Term
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Definition
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Term
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Definition
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Term
| What does scavenger receptor (class A) bind? |
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Definition
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