Lipids and Lipoproteins (CC Lec) Are amphipathic lipid molecules, are found on the surface of
Increasingly important in clinical practice lipid layers. The polar hydrophilic head group faces outward
Are central to the energy source of metabolism of the body toward the aqueous environment. While the fatty acid chains
Since high fat consumption is associated between the blood face inward away from the water in a perpendicular orientation
lipid levels in blood this actually results to the association of with respect to the lipid surface.
atherosclerosis and with coronary heart disease (CHD)
CHOLESTEROL
Lipids (fats) Function: Can be good and bad cholesterol
Composed of carbon-hydrogen branch which are a rich source Is an unsaturated steroid alcohol
of energy and an efficient way for the body to store excess Containing four rings (A, B, C, and D), and it has a single
calories C-H side chain tail similar to a fatty acid in its physical
Because of their unique physical property, lipids are integral properties
part in cell membranes. Therefore, they play an important Is an amphipathic lipid, found on the surface of lipid
structural role in cells layers along with phospholipids
The lipid is transported by lipoproteins, namely; Though amphipathic in nature, can be converted for Vit. D
o Triglycerides, phospholipids, cholesterol, and synthesis (Vit. D3)
cholesteryl esters are also known to be found in Only having the hydrophilic part which contains the
cells. hydroxyl group in the A-ring
Cholesterol is not readily catabolized by most cells;
FATTY ACIDS therefore, it does not serve as a source of fuel.
In plasma, most are bound to albumin o However, it can be converted in the liver to
Describe to have simple linear chains of carbon-hydrogen primary bile acids (cholic acid), promoting fat
bonds that permeate to a carboxyl group absorption in the intestine.
In plasma, only a relatively small amount of fatty acids A small amount of cholesterol can be converted by some
exists in the free or known to be unesterified form because tissue which actually produces the hormones such as:
most of the fatty acids are bound to albumin. o Glucocorticoids, mineralocorticoids, and estrogens
Majority of plasma fatty acids are instead found as a Can also exist in an esterified form called cholesteryl
constituent of triglycerides or phospholipids ester.
Most fatty acids are composed of the long chain (>12 Cholesteryl ester
Carbon atoms) Hydrophobic (water fearing)
In our diet, the most common fatty acid that we get is from Neutral lipid (no charge)
the long chain fatty acid Located in the center of lipid drops and
lipoproteins, along with triglycerides
Classified according to length:
a. Short-chain (4-6 carbon atoms)
b. Medium-chain (8-12 carbon atoms)
c. Long-chain (>12 carbon atoms)
Classified according to Carbon-Carbon double bonds:
a. Saturated (no double bonds)
b. Monosaturated (one double- bond)
c. Polyunsaturated (two or more)
TRIGLYCERIDES
Predominantly found in plasma containing three fatty acid
molecules attached to one molecule of glycerol by ester LIPOPROTEINS
bonds Lipoproteins is composed of both lipids and proteins,
Containing saturated fatty acids: pack together more called apolipoproteins
closely and tend to be solid at room temperature The amphipathic cholesterol and phospholipid molecules
Containing cis unsaturated fatty acids: form oils at room are primarily found on the surface of lipoproteins as a
temperature (liquid) single monolayer
Most triglycerides are derived from plant sources such as The hydrophobic, neutral triglyceride and cholesteryl ester
corn, sunflower seeds are rich in polyunsaturated fatty acids. molecules are found in the central or core region.
Whereas, from animal sources are mostly saturated fatty
acids which solidify at room temperature. APOLIPOPROTEINS
There are no charged groups or polar hydrophilic groups → Help maintain the structural integrity of lipoproteins
Hydrophobic in nature and virtually water insoluble Serve as ligands for cell receptors
Classified as a neutral lipid (no charge) Serves as activators and inhibitors of the various enzymes
that modify
PHOSPHOLIPIDS Located on the surface of the lipoprotein particles
Are similar in structure to triglycerides except that they only
have two esterified fatty acids TYPES:
Contain various types of phospholipids are named based on A. Apolipoprotein (apo) A-I
the type of phospholipid head group present. Major protein on HDL (good cholesterol)
o Example: Phosphatidylcholine - contains a choline Frequently used as an index of the amount of the
head group and is the most common phospholipid antiatherogenic HDL present in plasma
found on lipoproteins and in cell membranes
Increasingly important in clinical practice lipid layers. The polar hydrophilic head group faces outward
Are central to the energy source of metabolism of the body toward the aqueous environment. While the fatty acid chains
Since high fat consumption is associated between the blood face inward away from the water in a perpendicular orientation
lipid levels in blood this actually results to the association of with respect to the lipid surface.
atherosclerosis and with coronary heart disease (CHD)
CHOLESTEROL
Lipids (fats) Function: Can be good and bad cholesterol
Composed of carbon-hydrogen branch which are a rich source Is an unsaturated steroid alcohol
of energy and an efficient way for the body to store excess Containing four rings (A, B, C, and D), and it has a single
calories C-H side chain tail similar to a fatty acid in its physical
Because of their unique physical property, lipids are integral properties
part in cell membranes. Therefore, they play an important Is an amphipathic lipid, found on the surface of lipid
structural role in cells layers along with phospholipids
The lipid is transported by lipoproteins, namely; Though amphipathic in nature, can be converted for Vit. D
o Triglycerides, phospholipids, cholesterol, and synthesis (Vit. D3)
cholesteryl esters are also known to be found in Only having the hydrophilic part which contains the
cells. hydroxyl group in the A-ring
Cholesterol is not readily catabolized by most cells;
FATTY ACIDS therefore, it does not serve as a source of fuel.
In plasma, most are bound to albumin o However, it can be converted in the liver to
Describe to have simple linear chains of carbon-hydrogen primary bile acids (cholic acid), promoting fat
bonds that permeate to a carboxyl group absorption in the intestine.
In plasma, only a relatively small amount of fatty acids A small amount of cholesterol can be converted by some
exists in the free or known to be unesterified form because tissue which actually produces the hormones such as:
most of the fatty acids are bound to albumin. o Glucocorticoids, mineralocorticoids, and estrogens
Majority of plasma fatty acids are instead found as a Can also exist in an esterified form called cholesteryl
constituent of triglycerides or phospholipids ester.
Most fatty acids are composed of the long chain (>12 Cholesteryl ester
Carbon atoms) Hydrophobic (water fearing)
In our diet, the most common fatty acid that we get is from Neutral lipid (no charge)
the long chain fatty acid Located in the center of lipid drops and
lipoproteins, along with triglycerides
Classified according to length:
a. Short-chain (4-6 carbon atoms)
b. Medium-chain (8-12 carbon atoms)
c. Long-chain (>12 carbon atoms)
Classified according to Carbon-Carbon double bonds:
a. Saturated (no double bonds)
b. Monosaturated (one double- bond)
c. Polyunsaturated (two or more)
TRIGLYCERIDES
Predominantly found in plasma containing three fatty acid
molecules attached to one molecule of glycerol by ester LIPOPROTEINS
bonds Lipoproteins is composed of both lipids and proteins,
Containing saturated fatty acids: pack together more called apolipoproteins
closely and tend to be solid at room temperature The amphipathic cholesterol and phospholipid molecules
Containing cis unsaturated fatty acids: form oils at room are primarily found on the surface of lipoproteins as a
temperature (liquid) single monolayer
Most triglycerides are derived from plant sources such as The hydrophobic, neutral triglyceride and cholesteryl ester
corn, sunflower seeds are rich in polyunsaturated fatty acids. molecules are found in the central or core region.
Whereas, from animal sources are mostly saturated fatty
acids which solidify at room temperature. APOLIPOPROTEINS
There are no charged groups or polar hydrophilic groups → Help maintain the structural integrity of lipoproteins
Hydrophobic in nature and virtually water insoluble Serve as ligands for cell receptors
Classified as a neutral lipid (no charge) Serves as activators and inhibitors of the various enzymes
that modify
PHOSPHOLIPIDS Located on the surface of the lipoprotein particles
Are similar in structure to triglycerides except that they only
have two esterified fatty acids TYPES:
Contain various types of phospholipids are named based on A. Apolipoprotein (apo) A-I
the type of phospholipid head group present. Major protein on HDL (good cholesterol)
o Example: Phosphatidylcholine - contains a choline Frequently used as an index of the amount of the
head group and is the most common phospholipid antiatherogenic HDL present in plasma
found on lipoproteins and in cell membranes
