Crop Handout LEC 4 Lipids Structure and Function PDF

Far Eastern University Institute of Arts and Sciences Department of Mathematics MTY1107 and BIO1105 Lecture Module 4 LIPIDS STRUCTURE AND FUNCTION Oil droplet...

Far Eastern University Institute of Arts and Sciences Department of Mathematics MTY1107 and BIO1105 Lecture Module 4 LIPIDS STRUCTURE AND FUNCTION Oil droplets in water. The observed colors are due to light interference. RETRIEVED: https://www.photocrowd.com/ photos/bubbling-over-1120146.abd106648/  Far Eastern University LEC 4 MODULE OUTLINE Institute of Arts and Sciences Department of Mathematics - Chemistry 1. Overview of Lipids 5. Signalling Lipids What are Lipids? Eicosanoids Classification of Lipids Prostaglandins Thromboxanes 2. Structural Features of Lipids Leukotrienes 3. Storage Lipids Steroids Triacylglycerol Cholesterol 4. Structural Lipids Phospholipids Glycerophospholipids Sphingolipids Glycolipids Glycosphingolipids Galactolipids  Far Eastern University LEC 4 OVERVIEW OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Lipids substances of biological origin which are insoluble in water. unlike other biomolecules, they are not polymeric Their biological roles can be generally subdivided into three: Energy Storage Structural Components Cell Signalling Adipocytes in breast tissue Lipid bilayer Cortisol  Far Eastern University LEC 4 OVERVIEW OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Classification of Lipids lipids are usually classified according to their biological function Each lipid classification also has common structural features  Far Eastern University LEC 4 Institute of Arts and Sciences Department of Mathematics - Chemistry Structural Features of Lipids Fatty Acids Glycerol Sphingosine  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids are carboxylic acids with The Common Biological Fatty Acids hydrocarbon chains from 4 to 36 Carbon long in higher plants and animals, the most common are C 16 and C 18 can either be saturated or unsaturated their physical properties are dependent on the length of hydrocarbon chain and the degree of unsaturation  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Saturated Fatty Acids unbranched Palmitic acid fully saturated with H atoms has a higher melting point highly flexible molecules Stearic acid Unsaturated Fatty Acids contains one or more double bonds can either be cis or trans (mostly are cis) has a lower melting point Oleic acid majority of biological fatty acids Explain the difference in melting points  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Nomenclature of Fatty Acids Steps in the Systematic (IUPAC) Naming of Fatty Acids 1) Assign C-1 to the carboxyl carbon 2) Assign C-2 as the ɑ-Carbon 3) From C-1, count the total number of C atoms in the hydrocarbon chain 18 Carbons = Octadeca- 4) For every double bond, indicate the locant number as well as if it is cis or trans cis-9-Octadecenoic acid  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Nomenclature of Fatty Acids Steps in Naming Using the 𝚫-x Notation (Obsolete) 1) Assign C-1 to the carboxyl carbon 2) Assign C-2 as the ɑ-Carbon 3) From C-1, count the total number of C atoms in the hydrocarbon chain 18 4) To take into account the position of the double bond(s), indicate the overall number of double bonds (1), followed by 𝚫 , and lastly, the locant number (9) of the double bond(s) in superscript 9 18:1𝚫  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Nomenclature of Fatty Acids Steps in Naming Using the 𝝎-x or n-x* Notation 1) Assign C-1 (𝛚/n) to the methyl terminal end Carbon 2) From C-1, count the total number of C atoms in the hydrocarbon chain 20 3) From C-1, indicate the locant number of the first double bond 3 4) After the total number of C atoms, combine (𝛚/n) with the locant number of the first double bond 20:𝛚-3 or 20:n-3 *IUPAC recommends the use of the “n” instead of the “𝝎” symbol  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Nomenclature of Fatty Acids Give the systematic name, 𝚫-x name, and the 𝝎-x name for the following: Are there any 𝝎-3 and 𝝎-6 fatty acids?  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Physical Properties of Fatty Acids The physical properties of fatty acids depend on the Length and Degree of Unsaturation of the hydrocarbon chain. The longer the length and the lower the degree of unsaturation of the hydrocarbon chain, the more insoluble the fatty acid is in water. Foods high in saturated fatty acids include animal fats, while most plant oils such as olive oil, are high in unsaturated fatty acids. Why are foods that are high in saturated fatty acids said to be unhealthy?  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Physical Properties of Fatty Acids cis-Fatty Acids v. trans-Fatty Acids During the industrial processing of oils, cis unsaturated fatty acids are partially hydrogenated cis double bond at C-9 to to produce more saturated fatty acids. Since the molecules of saturated fatty acids can Hydrogenation pack closely together and become solid, oils high in saturated fats are much more stable and resistant to becoming rancid. However, some of the fatty acids are isomerized to trans unsaturated fatty acids which have been trans double bond at C-9 found to have negative health effects in humans.  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Physical Properties of Fatty Acids cis-Fatty Acids v. trans-Fatty Acids Trans fatty acids have been shown to cause the following Trans fatty acid content of common fast food items adverse health effects in humans: Increase in low-density lipoprotein in the Liver; Coronary Heart disease Cancer Diabetes  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Fatty Acids Linoleic acid (𝝎-6) and ɑ-Linoleic acid (𝝎-3) are termed Physical Properties of Fatty Acids as essential fatty acids because the human body is incapable of synthesizing them and must be obtained The Essential Fatty Acids: 𝝎-6 and 𝝎-3 through the diet. Linoleic acid (𝝎-6) is the precursor of Arachidonic acid (slide 30). ɑ-Linoleic acid (𝝎-3) is the precursor of Docosahexaenoic acid (DHA), an important component of the human Brain.  Far Eastern University LEC 4 STRUCTURAL FEATURES OF LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Glycerol naturally occuring alcohol Glycerol. Drawn in condensed structural formula (left) and bond line structure (right) forms the backbone of triacylglycerols Sphingosine an 18-Carbon amino alcohol forms the backbone of sphingolipids Sphingosine. Drawn in condensed structural formula (left) and bond line structure (right)  Far Eastern University LEC 4 Institute of Arts and Sciences Department of Mathematics - Chemistry Storage Lipids Triacylglycerols Waxes  Far Eastern University LEC 4 STORAGE LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Triacylglycerols also called triglycerides or fats the most abundant class of lipids, as they serve as energy stores in animals, namely in adipocytes Consists of a Glycerol esterified to three fatty acid residues Simple Triacylglycerol Mixed Triacylglycerol  Far Eastern University LEC 4 STORAGE LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Triacylglycerols Reactions of Triacylglycerols Hydrogenation In slide 13, you learned that in the industrial processing of oils rich in unsaturated fatty acids, the reduction of double bonds is done to convert them to solid, saturated fatty acids. This is usually done in the large scale using Hydrogen gas over a catalyst (Pt or Pd). Identify the fatty acid composition of the triacylglycerols above  Far Eastern University LEC 4 STORAGE LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Triacylglycerols Reactions of Triacylglycerols Saponification Saponification or the process of making soap from fats or oils, is one of the oldest chemical reactions known to humans Fats or Oils are reacted with a base to form a surfactant (soap) in a hydrolysis reaction. What is a surfactant?  Far Eastern University LEC 4 STORAGE LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Waxes esters of fatty acids and alcohols The fatty acids in waxes are usually saturated The alcohols in waxes can be saturated The General Formula of a Wax or unsaturated Waxes are highly insoluble in water Lanolin is Carnauba wax, usually used as isolated from the a base for Carnauba palm pharmacuetical tree, is used as products floor and (Olay®) automobile wax Draw the line-bond structure for Stearyl palmitate and Triacontanol palmitate  Far Eastern University LEC 4 Institute of Arts and Sciences Department of Mathematics - Chemistry Structural Lipids Phospholipids Glycolipids  Far Eastern University LEC 4 STRUCTURAL LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Phospholipids Glycerophospholipids also called phosphoglycerides the major lipid component of animal biological membranes are amphipilic molecules glycerophospholipids have X glycerol as their backbone Phosphatidic acid. The – X refers to different polar “head” groups esterified to the compound molecule most glycerophospholipids Amphipilic have phosphatidic acid as – molecules which have both a the parent compound polar and non-polar part  Far Eastern University LEC 4 STRUCTURAL LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Phospholipids Glycerophospholipids X The Derivatives of Phosphatidic Acid Phosphatidic acid Name of – X Structure of – X Glycerophospholipid Choline Phosphatidylcholine Ethylamine Phosphatidylethanolamine  Far Eastern University LEC 4 STRUCTURAL LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Phospholipids Glycerophospholipids X The Derivatives of Phosphatidic Acid Phosphatidic acid Name of – X Structure of – X Glycerophospholipid Serine Phosphatidylserine myo-Inositol Phosphatidylinositol  Far Eastern University LEC 4 STRUCTURAL LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Phospholipids Sphingolipids Class of lipids which is also, usually found in biological membranes In contrast with glycerophospholipids, sphingolipids have sphingosine Sphingosine. The amine as their backbone molecule (highlighted in yellow) of sphingosine can be replaced with other groups. Sphingosine is synthesized by the body by reacting palmitoyl-CoA with an amino acid. What amino acid does the head group resembles?  Far Eastern University LEC 4 STRUCTURAL LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Phospholipids Sphingolipids The Derivatives of Sphingosine Choline Sphingosine Ceramide Sphingomyelin Ceramides Choline make up sphingomyelins approximately are usually found 30-40% of the in the cell lipids found in membranes of skin cells tissues in the nervous system  Far Eastern University LEC 4 STRUCTURAL LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Glycolipids Glycosphingolipids Class of lipids which is found in the Ceramide outer plasma membrane Consists of a ceramide (fatty acid residue) connected to one or more carbohydrate residues Plays important roles in cellular adhesion, cellular recognition, and cell signalling  Far Eastern University LEC 4 STRUCTURAL LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Glycolipids Glycosphingolipids The Derivatives of Ceramide Ceramide Cerebroside Gangliosides ceramides with a ceramides with monosaccharide oligosaccharides attached attached found in the used in cellular membranes of signalling and nerve cells recognition.  Far Eastern University LEC 4 STRUCTURAL LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Glycolipids Galactolipids also called Sulfolipids the major lipid component of plant cell Makes up approximately 70-80% of plant lipids in chloroplasts Gangliosides  Far Eastern University LEC 4 Institute of Arts and Sciences Department of Mathematics - Chemistry Signalling Lipids Eicosanoids Steroids  Far Eastern University LEC 4 SIGNALLING LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Eicosanoids Eicosanoids are paracrine hormones Paracrine Hormones – hormones that act only on so-called because all of them are derived from nearby cells or organs Arachidonic acid (a 20-Carbon polyunsaturated fatty acid) Eicosanoids can be classified into three: Eicosanoids are mediators of Prostaglandins, Thromboxanes, and Leukotrienes the following: inflammation fever and pain progression or termination of pregnancy regulation of blood pressure menstruation Arachidonic acid (as Arachidonate) (IUPAC Name: cis-, cis-, cis-, cis-5,8,11,14-Icosatetraenoic acid)  Far Eastern University LEC 4 SIGNALLING LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Eicosanoids Prostaglandins Leukotrienes have a 5-Carbon ring produced by immunocompetent found in almost all tissues of cells such as leukocytes, mast cells, basophils, eosinophils, & the human body. Thromboxanes neutrophils. plays a variety of functions, have a 6-Carbon ring including but not limited to: produced by platelets. plays a vital role in the pro-inflammatory effects contraction and relaxation of the contraction and relaxation plays a vital role in blood clot smooth muscles of the Lungs. of smooth muscles formation regulation of the sleep- Explain how Eicosanoids are affected by Non- wake cycle. Steroidal Anti-Inflammatory Drugs (NSAIDs)  Far Eastern University LEC 4 SIGNALLING LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Steroids Steroids are a large, terpene- Terpenes based class of lipids. – unsaturated hydrocarbons formed by linking two or All steroids have a common more isoprene (right) units. structural motif consisting of four (4) rings fused together. The most common steroid and the precursor of all animal steroids is Cholesterol Cholesterol As with most other lipids, cholesterol is amphipathic, with a polar head group (–OH) and a non-polar body (steroid nucleus). Steroid derivatives will be further discussed in LEC Module 6 Hormones  Far Eastern University LEC 4 SIGNALLING LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Steroids Cholesterol Cholesterol is synthesized by all animal cells from Acetyl-CoA Cholesterol Cholesterol is an important component of animal cell plasma membrane as it regulates the fluidity of the membrane. Cholesterol is also a vital part of blood lipoproteins and is the precursor of all sex and steroid hormones. Aside from being a signalling lipid, cholesterol also functions as a A computer model of a structural lipid in the epidermis of realistic lipid bilayer the Skin.  Far Eastern University LEC 4 SIGNALLING LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Steroids Cholesterol While essential to survival, excess cholesterol can cause advserse health effects. Cholesterol Since cholesterol is naturally synthesized by the body, healthcare professionals recommend to limit the consumption of cholesterol, “as much as possible” Hypercholesterolemia or excess cholesterol have been shown to lead to increase risk of Heart attack, Stroke, and Cancer. Gallstones are almost pure cholesterol Xanthelasma are cholesterol deposits around the face  Far Eastern University LEC 4 SIGNALLING LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Steroids Cholesterol Lipoproteins: The Carriers of Cholesterol Lipoproteins are molecules whose primary function is to transport cholesterol, triacylglycerols, and other hydrophilic biomolecules. Lipoproteins can be classified into four (4) types: 1. High-Density Lipoprotein (HDL) 2. Low-Density Lipoprotein (LDL) 3. Very Low-Density Lipoprotein (VLDL) A diagram of a 4. Chylomicrons Low-Density Lipoprotein (LDL)  Far Eastern University LEC 4 SIGNALLING LIPIDS Institute of Arts and Sciences Department of Mathematics - Chemistry Steroids Cholesterol Lipoproteins: The Carriers of Cholesterol Composition and Properties of Human Lipoproteins Based on the given compositions, which of the following can be classified as “Bad Cholesterol”?