Quiz 3: Lipids and Lipoproteins Flashcards Preview

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Flashcards in Quiz 3: Lipids and Lipoproteins Deck (31)
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1

Triglyceride Transport (Exogenous Transport)

Via chylomicrons and VLDL
Dietary lipids absorbed and assembled with ApoB-48 into chylomicrons which are broken down in circulation to triglyceride and chylomicron remnants for metabolism or recycling through the liver.
Lipoprotein lipase frees Free fatty acids and glycerol from Triglycerides

2

Triglyceride Metabolism

Release of Fatty Acids from cells for energy, recycling of glycerols into triglycerides
Lipase, lipoprotein lipase, epinephrine and cortisol break down triglycerides

3

Cholesterol Forms

Unsaturated steroid alcohol when esterified: fatty acid attached with ester bond
Free form is unsterified

4

Cholesterol Precursors

Bile acids, steroid hormones, and Vit D

5

Cholesterol Transport

LDL is primary carrier

6

Lipoprotein (Definition)

Molecules that combine insoluble dietary lipids with water soluble proteins for transport; micelles are spherical with an inner core of neutral fat

7

Chylomicrons (Definition)

Largest lipoprotein with lowest density, form in intestines to transport triglycerides; normally enter circulation and are metabolized then taken to the liver to be further modified
They are 86% Triglyceride

8

VLDL

Carries triglycerides synthesized in liver (endogenous transport); normally secreted into blood from liver (after being packaged in VLDL) to be metabolized in peripheral tissues into triglycerides and VLDL remnants or intermediate density lipoproteins for use in metabolism or recycling through the liver
Apo B is the major protein

9

IDL

intermediate-density-lipoprotein
Transitional form between VLDL and LDL, they carry endogenous triglycerides and cholesterol esters

10

LDL

Major cholesterol carrier, largely endogenous cholesterol
Easily taken up by cells, and are thus assoc. with athlerosclerosis
Normally brings cholesterol to peripheral cells for membrane synthesis and hormone creation --> Infiltrate into extracellular space of vessel wall and cleared by macrophages (Macrophages with too much lipid may turn into foam cells which may be plaque precursors)
Apo B is the major protein

11

HDL

Made in the liver and intestine of recycled chylomicron and VLDL molecules; normally removes excess cholesterol from peripheral tissues (antiatherogenic effect)
Apo A-1 is the major protein

12

Lp(a)

Mostly cholesterol esters, phospholipids, and apolpoprotein (a)
Elevated levels are assoc. with coronary heart disease, heart attack, and cerebrovascular disease

13

Cholesterol Ranges

Total: < 200, high: >240
HDL: > 60, at risk for heart disease: < 40
LDL: < 100, High: 160-189

14

Lipid soluble Vitamins

A,D,E, and K

15

Time needed to utilize different energy sources

Glucose - minutes
Glycogen- 1 day
Protein - 10 day
Lipids - 30-40 days with water

16

Functions of cholesterol

Precursor of steroid hormones
Cell membrane component
Precursor of bile salts

17

Apolipoprotein

The protein portion of the transport molecule, free of the lipid component
Apolipoprotein A: major portion of HDL
Apolipoprotein B: major portion of LDL
Apolipoprotein C: major protein of VLDL and Chylomicrons
large: apoB (B-48 and B-100): atherogenic
smaller: apoA-I, apoC-II, apoE

18

Cholesteryl ester

A compound of cholesterol and a fatty acid

19

Plasma Lipid Components

Cholesterol, Trigylcerides, Phospholipids, and non-esterified fatty acids

20

Normal proportions of lipoproteins

LDL: 60-70%
HDL: 20-35%
VLDL: 5-12% (Very Low Density Lipoproteins)

21

Triglycerides Function

Primary form of lipid storage

22

Cholesterol Function

Important in cellular physiology, a precursor to Steroid hormones
LDL takes it to cells, HDL takes it out of cells

23

Chylomicrons Function

Dietary (exogenous) triglycerides

24

VLDL Function

Endogenous triglycerides

25

LDL Function

Cholesterol to cells

26

HDL Function

Cholesterol out of cells

27

Triglyceride Testing Methods

Enzymes are the best method, usually involving freeing glycerol by lipase

28

HDLc

Direct/Homogeneous assays measure without pretreatment
Indirect methods remove chylomicrons, VLDL, and LDL through precipitation

29

LDLc

Direct/Homogeneous assays measure without pretreatment

30

Friedewald Method

Calculation of LDLc and VLDLc when Triglycerides are