Lipids of Physiologic Significance Flashcards
Properties of lipids:
(1) Relatively insoluble in water
(2) Soluble in nonpolar solvents such as ether and chloroform
It is where 💡fat is stored.
It also serves as a 💡thermal insulator.
ADIPOSE TISSUE
Nonpolar lipids act as (1)__, allowing rapid propagation of (2)__ along myelinated nerves
(1) Electrical insulators
(2) Depolarization waves
They transport lipids in the blood.
Lipoprotein
Lipids are classified as:
Simple lipids
Complex lipids
Example of simple lipids:
Fats and waxes
Examples of complex lipids:
Phospholipids and Glycolipids
These are 💡esters of fatty acids with 💡various alcohols
Simple Lipids
These are simple lipids which are 💡esters of fatty acids with 💡glycerol.
Fats
These are fats in the 💡liquid state.
Oils
These are simple lipids which are 💡esters of fatty acids with 💡higher molecular weight monohydric alcohols.
Waxes
These are 💡esters of fatty acids containing groups in addition to an 💡alcohol and 💡one or more fatty acids.
Complex lipids
Lipids containing, in addition to fatty acids and an alcohol, a 💡phosphoric acid residue.
Phospholipids
It is an alcohol present in many 💡phospholipids.
GLYCEROL
It is an alcohol present in 💡spingophospholipids.
SPHINGOSINE
Lipids containing a 💡fatty acid, 💡sphingosine, and 💡carbohydrate.
Glycolipids (glycosphingolipids)
Examples of neutral lipids:
Acylglycerols (glycerides)
Cholesterol
Cholesteryl esters
These are 💡aliphatic carboxylic acids
They occur in the body mainly as esters in natural fats and oils
Fatty Acids
These are 💡unesterified form and a 💡transport form in the plasma.
Free Fatty Acids
Fatty acids that occur in natural fats usually contain an __.
Even number of carbon atoms
It is a term when the fatty acid chain contains 💡no double bonds.
SATURATED FATTY ACIDS
It is a term when the fatty acid chain contains 💡one or more double bonds.
UNSATURATED FATTY ACIDS
Saturated fatty acids ends in?
-anoic
Unsaturated fatty acids with double bonds ends in?
-enoic
Carbon atoms are numbered from the (1)__ (carbon no. 1). The carbon atoms adjacent to the carboxyl carbon (nos. 2, 3, and 4) are also known as the (2)__, respectively, and the terminal methyl carbon is known as the (3)__.
(1) Carboxyl carbon
(2) α, β, and γ carbons
(3) ω- or n-carbon
It is use for indicating the 💡number and 💡position of the double bonds
Δ
Fatty acids containing 💡one double bond
Monounsaturated
Fatty acids containing 💡two or more double bonds
Polyunsaturated
These fatty acids are derived from 💡eicosa (20-carbon) polyenoic fatty acids.
Eicosanoids
They are synthesized 💡in vivo by 💡cyclization of the center of the carbon chain of 20-carbon (eicosanoic) polyunsaturated fatty acids (eg, arachidonic acid) to form a cyclopentane ring
Prostaglandins
They have the 💡cyclopentane ring interrupted with an oxygen atom 💡(oxane ring)
Thromboxanes
It is a saturated fatty acid with 💡2 carbon atoms
Acetic acid
It is a saturated fatty acid with 💡4 carbon atoms
Butyric Acid
It is a saturated fatty acid with 💡5 carbon atoms
Valeric Acid
It is a saturated fatty acid with 💡6 carbon atoms
Caproic Acid
It is a saturated fatty acid with 💡12 carbon atoms
Lauric Acid
It is a saturated fatty acid with 💡14 carbon atoms
Myristic Acid
It is a saturated fatty acid with 💡16 carbon atoms
Palmitic Acid
It is a saturated fatty acid with 💡18 carbon atoms
Stearic Acid
Most naturally occurring unsaturated fatty acids have? __.
Cis double bonds
The carbon chains of saturated fatty acids form a (1)__ when extended at (2)__. At (3)__, some bonds rotate, causing (4)__, which explains why biomembranes become thinner with increases in temperature.
(1) Zigzag pattern
(2) Low temperatures
(3) Higher temperatures
(4) Chain shortening
These are present in certain foods, arising as a 💡by-product of the saturation of fatty acids during 💡hydrogenation, or 💡“hardening,” of natural oils in the manufacture of margarine.
Trans fatty acids
It is the 💡trans isomer of oleic acid.
Elaidic acid
A triacylglycerol containing three saturated fatty acids of 12 carbons or more is (1)__ at body temperature, whereas if the fatty acid residues are polyunsaturated, it is (2)__ to below 0°C.
(1) Solid
(2) Liquid
Give examples of omega-3-fatty acids:
Alpha-linolenic (ALA)
Eicosapentaenoic (EPA)
Docosahexaenoic (DHA)
These are fatty acids that have 💡anti-inflammatory effects, perhaps due to their effects in promoting the synthesis of less inflammatory prostaglandins and leukotrienes as compared to ω6 fatty acids
Long chain ω3 fatty acids
It is a long chain ω3 fatty acid found in 💡plant oils.
Alpha-linolenic (ALA)
It is a long chain ω3 fatty acid found in 💡fish oils
Eicosapentaenoic (EPA)
It is a long chain ω3 fatty acid found in 💡fish and algal oils
Docosahexaenoic (DHA)
These are esters of the 💡trihydric alcohol glycerol and fatty acids.
These are the 💡main storage forms of fatty acids.
Triacylglycerols (Triglycerides)
The __of glycerol are not identical when viewed in three dimensions.
Carbons 1 and 3
Glycerol is always phosphorylated on (1)__ by (2)__ to give (3)__ and not glycerol-1-phosphate
(1) sn-3
(2) Glycerol kinase
(3) Glycerol-3-phosphate
These are 💡derivatives of phosphatidic acid, in which the 💡phosphate is esterified with one OH group of glycerol and the other two OH groups are esterified to two long chain fatty acids (glycerophospholipids).
Phospholipids
These are the 💡main lipid constituents of membranes.
Phospholipids
It is important as an 💡intermediate in the synthesis of triacylglycerols as well as phosphoglycerols but is not found in any great quantity in tissues.
Phosphatidic acid
Glycerophospholipids containing choline which are the 💡most abundant phospholipids of the cell membrane and 💡represent a large proportion of the body’s store of choline.
Phosphatidylcholines (Lecithins)
-
Choline
-
Acetylcholine
It is a very effective 💡surface-active agent and a 💡major constituent of the surfactant preventing adherence, due to surface tension, of the inner surfaces of the lungs.
Dipalmitoyl lecithin
💡Absence of dipalmitoyl lecithin from the lungs of premature infants causes?
Respiratory Distress Syndrome
-
Phosphatidylethanolamine (cephalin)
It plays a role in 💡apoptosis (programmed cell death)
Phosphatidylserine
These are found in the 💡outer leaflet of the cell membrane lipid bilayer and are particularly abundant in specialized areas of the plasma membrane known as 💡lipid rafts.
They are also found in large quantities in the 💡myelin sheath that surrounds nerve fibers.
They are believed to play a role in 💡cell signaling and in 💡apoptosis.
Sphingomyelins
It is the combination of 💡sphingosine plus fatty acid which is a structure also found in the glycosphingolipids
Ceramide
These are 💡phosphorylated phosphatidylinositols which are a minor components of cell membranes, but play an important part in 💡cell signaling and 💡membrane trafficking.
Phosphoinositides
It is a 💡precursor of second messengers.
Phosphatidylinositol
It is the 💡major lipid of mitochondrial membranes.
It is only found in the 💡mitochondria and is essential for the mitochondrial function.
Cardiolipin
These are 💡intermediate in the metabolism of phosphoglycerols
Lysophospholipids
It is found in 💡oxidized lipoproteins and has been implicated in some of their effects in promoting 💡atherosclerosis.
Lysophosphatidylcholine (lysolecithin)
These compounds constitute as much as 10% to 30% of the phospholipids of brain and heart.
They resemble phosphatidylethanolamine but possess an 💡ether link on the sn-1 carbon instead of the ester link found in acylglycerols.
Plasmalogens
These are lipids with an attached 💡carbohydrate or carbohydrate chain.
They are widely distributed in every tissue of the body, particularly in 💡nervous tissue such as brain.
Glycolipids
Gycolipids occur particularly in the outer leaflet of the plasma membrane, where they contribute to (1)__ which form the (2)__.
(1) Cell surface carbohydrates
(2) Glycocalyx
It is the 💡major glycolipids found in animal tissues
They contain 💡ceramide and 💡one or more sugars.
Glycosphingolipids
It is a 💡major glycosphingolipid of brain and other nervous tissue, found in relatively low amounts elsewhere.
Galactosylceramide
It is a 💡galactosylceremide with a 💡sulfo group attached to the O in the three position of galactose and is present in high amounts in myelin.
Sulfogalactosylceramide (sulfatide)
It resembles galactosylceramide, but the head group is glucose rather than galactose.
It is the predominant simple glycosphingolipid of 💡extraneural tissues, also occurring in the brain in small amounts.
Glucosylceramide
These are complex glycosphingolipids derived fro glucosylceramide that contain in addition one or more molecules of 💡sialic acid.
These are present in nervous tissues in high concentration.
Gangliosides
It is the 💡principal sialic acid found in human tissues.
Neuraminic Acid
Functions of gangliosides:
- Cell-cell recognition and communication
2. Receptors for hormones and bacterial toxins (e.g. cholera toxin)
It is the simplest ganglioside found in tissues which contains ceramide, one molecule of glucose, one molecule of galactose, and one molecule of NeuAc.
GM3
It is a 💡precursor of a large number of equally important steroids that include the bile acids, adrenocortical hormones, sex hormones, vitamin D, and cardiac glycosides.
Cholesterol
It is widely distributed in all cells of the body but particularly in nervous tissue.
It is a 💡major constituent of the plasma membrane and of plasma lipoproteins
Cholesterol
It a form of cholesterol where the💡 hydroxyl group on position 3 is 💡esterified with a long-chain fatty acid.
Cholesteryl ester
-
Ergosterol
It is a polyprenoids which participates in the 💡respiratory chain in mitochondria.
Ubiquinone
It is a polyprenoids which is a long-chain alcohol that takes part in glycoprotein synthesis by transferring carbohydrate residues to asparagine residues of the polypeptide (s
Dolichol
Lipid peroxidation is a source of?
These are molecules that have 💡unpaired valence electrons, making them highly reactive
Free radicals
-
Peroxidation (auto-oxidation)
These are 💡produced during peroxide formation from fatty acids containing methylene-interrupted double bonds, that is, those found in the naturally occurring polyunsaturated fatty acids
Reactive Oxygen Species (ROS)
It is a chain reaction providing a continuous supply of ROS that initiate further peroxidation and thus has potentially devastating effects.
Lipid peroxidation
It is use to 💡control and reduce lipid peroxidation, both humans in their activities and nature
Antioxidants
These are examples of antioxidants that are used as food additives.
Propylgallate Butylated hydroxyanisole (BHA), Butylated hydroxytoluene (BHT)
These are naturally occurring antioxidants:
Vitamin E (Tocopherol)
Urate
Vitamin C
2 classes of antioxidants:
(1) Preventive antioxidants
(2) Chain-breaking antioxidants
It is a class of antioxidant which 💡reduce the rate of chain initiation.
EXAMPLES: catalase, peroxidases
Preventive antioxidants
It is a class of antioxidant which 💡interfere with chain propagation.
Chain-breaking antioxidants
It is the 💡principal chain-breaking antioxidants in vivo.
It acts in the aqueous phase to trap superoxide free radicals ( O2 ) urate, and vitamin E, which acts in the lipid phase to trap ROO• radicals .
Superoxide dismutase
When a critical concentration of these lipids is present in an aqueous medium, they form __.
Micelles
These may be formed by 💡sonicating an amphipathic lipid in an aqueous medium.
Liposomes
Clinical use of liposomes;
- Carriers of drug in the circulation.
- Used for gene transfer into vascular cells.
- Carriers for topical and transdermal delivery of drugs and cosmetics.
These are much larger particles, formed usually by nonpolar lipids in an aqueous medium.
These are stabilized by emulsifying agents such as amphipathic lipids (eg, phosphatidylcholine), which form a surface layer separating the main bulk of the nonpolar material from the aqueous phase
Emulsions
