Lipids and Lipoproteins Vocabulary Flashcards

Vocabulary flashcards covering key terms, structures, metabolic pathways, disease processes, medications, and laboratory methods from the lecture on lipids and lipoproteins.

Lipids

Fats and fat-like substances that are hydrophobic, meaning they do not mix well with water, and are commonly found in oils, butter, waxes, hormones, and vitamins.

Saturated Fats

Fatty acids that are devoid of double bonds, form a linear chain, and are typically solid at room temperature.

Unsaturated Fats

Fatty acids that contain one or more double bonds, feature a bent chain, and are typically liquid at room temperature.

Oleic Acid

A monounsaturated omega-9 fatty acid ($18:1\,\Delta^9$) with the chemical structure $CH_3(CH_2)_7-CH=CH-(CH_2)_7-COOH$.

Linoleic Acid

A polyunsaturated omega-6 fatty acid ($18:2\,\Delta^{9,12}$) with the chemical structure $CH_3(CH_2)_4-CH=CH-CH_2-CH=CH-(CH_2)_7-COOH$.

Triglycerides

Lipids composed of a glycerol molecule attached to three fatty acids by ester bonds, serving as the body's primary storage form of unused calories.

Phospholipids

Lipids consisting of a glycerol backbone, two hydrophobic fatty acid tails, and a phosphate group attached to a polar hydrophilic head.

Cholesterol

An amphipathic unsaturated sterol alcohol containing four rings (A, B, C, D) and a C-H side tail, synthesized exclusively in animals.

Phytosterols

Plant sterols with structures similar to cholesterol that lower plasma LDL-C and HDL-C levels by interfering with intestinal absorption of cholesterol.

Apolipoproteins

Proteins located on the surface of lipoprotein particles that maintain structural stability, act as cell receptor ligands, and regulate lipid-modifying enzymes.

Apo A-I

The major protein component of HDL that activates lecithin:cholesterol acyltransferase (LCAT) and mediates reverse cholesterol transport.

Apo B-100

An apolipoprotein found in LDL and VLDL that acts as the ligand for the LDL receptor.

Apo B-48

An apolipoprotein produced by mRNA editing in the intestine, found in chylomicrons, and essential for transporting dietary triglycerides and cholesterol.

Chylomicrons

The largest and least dense lipoproteins ($10\,nm$ to $1,200\,nm$), containing Apo B-48 and responsible for delivering dietary lipids from the intestine to tissues.

Very Low-Density Lipoproteins (VLDL)

Triglyceride-rich lipoproteins produced by the liver that contain Apo B-100, Apo E, and Apo Cs and transport endogenous triglycerides to peripheral tissues.

Intermediate-Density Lipoproteins (IDL)

Transient VLDL remnants formed during the conversion of VLDL to LDL, possessing intermediate triglyceride and cholesterol content.

Low-Density Lipoproteins (LDL)

Major cholesterol-rich lipoproteins formed from VLDL lipolysis that contain Apo B-100 and deliver cholesterol to body cells via LDL receptors.

Lipoprotein (a) [Lp(a)]

An LDL-like particle containing Apo (a) linked to Apo B-100 by a disulfide bond, which competes with plasminogen to impair fibrinolysis.

High-Density Lipoproteins (HDL)

The smallest and densest lipoproteins synthesized by the liver and intestine, responsible for carrying excess cholesterol from body tissues back to the liver.

Lipoprotein X (LpX)

An abnormal lipoprotein lacking Apo B-100 that appears in cholestasis, biliary cirrhosis, or LCAT deficiency, composed mainly of phospholipids and non-esterified cholesterol.

Exogenous Pathway

The metabolic process that transports dietary lipids digested in the intestine to target tissues via chylomicrons.

Endogenous Pathway

The metabolic process that transports lipids synthesized or processed by the liver to peripheral tissues using VLDL, IDL, and LDL.

Reverse Cholesterol Transport Pathway

The metabolic process in which HDL collects excess cholesterol from peripheral cells and delivers it to the liver for processing or excretion.

Arteriosclerosis

A general term for the thickening and loss of elasticity in the walls of arteries.

Atherosclerosis

A specific type of arteriosclerosis caused by the inflammatory buildup of fats and cholesterol plaques in the subendothelial space of artery walls.

Xanthomas

Nodular lipid deposits in the skin that frequently indicate an underlying genetic lipid disorder.

Classic Bile Acid Sequestrants

Drugs (cholestyramine, colesevelam, colestipol) that bind bile acids in the intestine to force their excretion in stool, lowering hepatic cholesterol and LDL-C.

HMG-CoA Reductase Inhibitors (Statins)

Medications (e.g., lovastatin, atorvastatin) that block intracellular cholesterol synthesis by inhibiting HMG-CoA reductase, the rate-limiting enzyme in cholesterol production.

Ezetimibe

A lipid-lowering medication that inhibits intestinal cholesterol absorption by blocking the Niemann-Pick C1-Like 1 (NPC1-L1) transporter.

Hyperlipoproteinemia

A metabolic disease characterized by abnormal concentrations of serum lipoproteins in the blood due to defects in synthesis, transport, or catabolism.

Familial Hypercholesterolemia (FH)

A genetic lipid abnormality caused by mutations in cholesterol-regulating genes, resulting in severe elevations of LDL cholesterol from birth.

Hypobetalipoproteinemia

An inherited disorder characterized by unusually low levels of LDL cholesterol due to impaired production of Apo B-containing lipoproteins.

Hypoalphalipoproteinemia

A condition characterized by abnormally low blood levels of HDL cholesterol.

Friedewald Calculation

A mathematical formula used to estimate LDL cholesterol: $\text{LDL-C} = \text{Total Cholesterol} - \text{HDL-C} - \frac{\text{Triglycerides}}{5}$.

Precision

The agreement or reproducibility of repeated analytical test results on the same specimen, quantified by the Coefficient of Variation (CV).

Accuracy

The closeness of a measured laboratory test value to the true value.

Matrix Effect

The alteration of a test measurement caused by non-analyte components present in the blood specimen, such as proteins, salts, or other lipids.