ME03 - Lipid Significance Flashcards
Importance of Lipids
_fats, oils, steroids, waxes
Common Physical proprties of Lipids
Relatively insoluble in water soluble in nonpolar solvents
Important Dietary constituents
fat-soluble vitamins Micronutrients long chain omega-3 fatty acids
Where are lipids stored in the body
Adipose Tissue
Clinical Diseases that Involve Lipids
obesity, diabetes mellitus, and atherosclerosis
Classification of Lipids
- Simple lipids A. Fats- Triglycerols, Oils B. Waxes Do not have triglyceride ester of three fatty acids Fatty acid and alcohol esters 2. Complex lipids A. Phospholipids - lipid with phosphate grp Glycolipids (glycosphingolipids) - Other complex lipids - Lipoproteins 3. Precursor and derived lipids fatty acids, glycerol, steroids, other alcohols, fatty aldehydes, ketone bodies, hydrocarbons, lipid-soluble vitamins and micronutrients, and hormones
Fatty Acids are Aliphatic Carboxylic Acids, True or False
TRUE
Transport form in the plasma
Free Fatty Acids
Lipids that contain no double bonds
Saturated, Example: Acetic Acid (CH3COOH), Butyric(4) Valeric (5) Caproic (6) Lauric (12) Myristic (14) Palmitic (16) Stearic (18)
Lipids containing one or more double bonds
Unsaturated Example: Monounsaturated Polyunsaturated Eicosanoids - Eicosa (20-carbon) polyenoic fatty acids Prostanoids, Leukotrienes (LTs), Lipoxins (LXs)
Unsaturated fatty acids has a higher melting point than saturated fatty acids
TRUE
C16:0 or 16:0
Palmitic, No. of C = number of double bonds
C18:2 (9,12) w-carbon (methyl carbon)
Linoleic acid
C18:3 (9,12,15)
Linolenic acid
What are essential Lipids
Linoleic acid; Linolenic Acid (ADEK)
Essential Amino Acids needed since Linoleic and Linolenic Acid cannot be made by the human body
Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine + (Arginine for infants)
Is there such thing as an essential carbohydrates?
NO, THERE’S NONE.
Types of Geometric Isomerism
cis- If the acyl chains are on the same side of the bond (oleic acid) Double bonds in fatty acids Trans- If the acyl chains are on opposite sides (elaidic acid)
Most naturally occuring unsaturated fatty acid
Unsaturated fatty acids that have CIS-DOUBLE BONDS
Disease associated with trans and saturated fatty acids
Atherosclerosis
Trans double bonds are ____________
Unnatural. It causes decreased fluidity (Ex. Margarine)
Physical and Physiologic Properties of Fatty Acids
More saturated = More solid at body temperature Polyunsaturated= Liquid to below zero dec celsius membrane lipids| Hibernators
What are Omega 3 Faty Acids
_-linolenic (ALA) - Found in plant oils eicosapentaenoic (EPA) - found in fish oil docosahexaenoic (DHA) - found in fish and algal oils
Clinical Significance of Omega 3 Fatty Acids
anti-inflammatory effects promoting the synthesis of less inflammatory prostaglandins and leukotrienes cardiovascular disease Cancer Rheumatoid arthritis Alzheimer disease
Main storage forms of fatty acids
Triglycerides (C1 and C3 of glyceril are not identical when viewed in three dimensions)
Precursor of Phospholipids, Influence membranes and acts in Signalling
Phosphatidic Acid
Glycerophospholipids containing choline
Lecithins (phosphatidylcholine) most abundant phospholipids of the cell membrane
Why is Choline important?
Important in Nervous transmission, as acetylcholine, and as store of labile methyl groups
Phospholipid that acts as surfactant
Dipalmitoyl Lecithin contains Type II alveolar cells preventing adherence, due to surface tension, of the inner surfaces of the lungs
Clinical Significance of Dipalmitoyl lecithin as surfactant
Respiratory Distress Syndrome
Ethanolamine or serine, respectively, replaces choline
_Phosphatidylethanolamine (cephalin) and phosphatidylserine
Plays a role in apoptosis (programmed cell death)
_Phosphatidylethanolamine (cephalin) and phosphatidylserine
Found in the outer leaflet of the cell membrane lipid bilayer, lipid rafts, and myelin sheath
Sphingomyelins
Function of Sphingomyelins
Cell signaling and apoptosis
Phopholipid found only in mitochondria
Phosphatidylglycerol
Gives rise to Cardiolipin
Phosphatidylglycerol
Alterations in functions of Phosphatidylglycerol can result to
heart failure and hypothyroidism and aging
Gives rise to Lysolecithin important in the metabolism and interconversion of phospholipids found in oxidized lipoproteins
Lysophosphatidylcholine
Clinical Significance of Lysophosphatidylcholine
Atherosclerosis
Lipids with an attached carbohydrate or carbohydrate chain Widely distributed in every tissue of the body, particularly in nervous tissue; Occur partly in the outer leaflet of plasma membrane Contributes to Glycocalyx
Glycolipids
Major glycosphingolipid of brain and other nervous tissue
_Galactosylceramide
Galactosylceramide is converted to ______ which is present in high amounts in MYELIN
Sulfatide
Resembles galactosylceramide, head group is glucose rather than galactise
Glucosylceramide
Complex glycosphingolipids derived from glucosylceramide
Gangliosides
Function of Gangliosides
GM1 - Function in cell-cell recognition and communication and as receptors for hormones and bacterial toxins (cholera)
Predominant simply glycosphingoloid of extraneural tissues
Glucosylceramide
What is the precursor of Steroids
Cholesterol
Precursor of large number of employed steroids includes;
Bile Acids, Adrenocortical Hormones, Sex hormones, Vitamin D & Cardiac Glycosides
What is the precursor of Vitamin D
Ergosterol
Not steroids Related because they are synthesized, like cholesterol from Fivecarbon isoprene units Rubber, camphor, the fat-soluble vitamins A, D, E, and K, and _-carotene (provitamin A)
Polyprenoids
Polyprenoid that has Respiratory chain in mitochondria
Ubiquinone
Polyprenoid that takes part in glycoprotein synthesis
Dolichol
Auto-oxidation of lipids Responsible for rancidity of foods Damage to tissues in vivo Cancer, inflammatory diseases, atherosclerosis, and aging
Lipid Peroxidation
Molecules that have unpaired valence electrons Reactive oxygen species (ROS)
Free Radicals
Chain reaction providing continuous supply of ROS
Initiation - Propagation - Termination
2 classes of Antioxidants
- Preventive antioxidants Catalase| EDTA | DTPA | Glutathione peroxidase 2. Chain-breaking antioxidants Superoxide dismutase | vitamin E
Why are LIPIDS insoluble in water
Predominance of nonpolar (hydrocarbon) groups
Part of the molecule is hydrophobic, or water insoluble; and a part is hydrophilic, or water soluble
AMPHIPATHIC - Micelles, Liposomes