Role of Lipids PDF

BASC102A: The Role of Lipids **FATS (LIPIDS OR ETHER EXTRACT)** General: A. Made up (by % MW of C (77%), H (12%) and O (11%) B. Insoluble in water but soluble in organic solvents such as ether, benzene and chloroform. C. Fat will yield **[2.25 times more energy]** than carbohydrates or prote...

BASC102A: The Role of Lipids **FATS (LIPIDS OR ETHER EXTRACT)** General: A. Made up (by % MW of C (77%), H (12%) and O (11%) B. Insoluble in water but soluble in organic solvents such as ether, benzene and chloroform. C. Fat will yield **[2.25 times more energy]** than carbohydrates or proteins. D. They are compound that yield fatty acids and glycerol when hydrolyzed. **Functions:** **Deficiency and Abnormalities** **Classification of Lipids** A. Simple lipids- triglycerides (fats and oils) B. Compound lipids- glycolipids, lipoproteins, phospholipids C. Non-glycerol-based lipids- cholesterol, vitamin D, pigments Give 2 Examples Of A Lipid Fatty Acid - Basic constituents of other lipids - Consists of C atoms (2-24 C's) chain with a COOH at the end - Fatty acids don't accumulate in cells. They are quickly converted into glycerides.  Glycerides - made up of fatty acids + glycerol - can be monoglycerides (rare) with one fatty acid; diglycerides (common in membrane lipids) with two fatty acids; or triglycerides (common in fat deposits, adipocytes or fat cells) with three fatty acids. **Saturated Vs. Unsaturated FA** - [Saturated fatty acids-] are those fatty acids wherein all the carbon skeleton are filled up with hydrogen. - [Unsaturated fatty acids-] are those fatty acids wherein not all carbon skeleton are filled with hydrogen, it contained double bond. Chemically these are not stable products and cause rancidity. To make these fatty acids stable on storage, the carbon is being filled up with either hydrogen or halogen. **Hydrogenation** -- is the filling up of hydrogen at the double bond. **Halogenation**- is the filling of halogen at the double bond such halogen as iodine, chlorine or bromine. Difference Between Saturated and Unsaturated Fats \| Compare the \...  The following suffixes are used to describe the degree of unsaturation: **Rancidity-** This is the oxidation(decomposition) primarily of unsaturated fatty acids resulting in disagreeable flavors and odors. This process occurs slowly and spontaneously, and may be accelerated by light, heat, and certain minerals. It can be prevented through proper storage and addition of BHA (butylated hydroxyanisole). **Hydrogenation(Hardening)-**This process adds hydrogen to the double bonds of unsaturated fatty acids. The result of hydrogenation is harder fat because of adding hydrogen increases the melting temperature.. This improves the keeping qualities of vegetable shortenings **Essential Fatty Acids** Cannot be synthesized by the animal or at least not in sufficient amount to prevent pathological effects and hence must be supplied: - Linoleic (C18:2) and Linolenic (C18:3) apparently cannot be synthesized by animal tissue, or at least not in sufficient amount to prevent pathological changes and must be supplied in the diet. - Arachidonic acid (C20:4) can be synthesized from C18:2, and therefore is required in the diet only if C18:2 is absent **Omega 3 Fatty Acids** Found in fish oils and seed oils (highest in linseed oil) **Triglycerides** Made up of fatty acids and glycerol (some other alcohol) bound together by ester bond What are triglycerides **Triglycerides (Fat vs. Oil)** - Stored fat accumulates as triglyceride. Excess can deposit as plaque in arteries. - **Animal Fat-** saturated triglyceride. Solid at room temperature (bacon, fat, lard, butter) - **Plant Fat (Oil)-** unsaturated triglyceride. Liquid at room temperature -- oils (olive oil, peanut oil, safflower oil, etc) Coconut fat (found in the white coconut meat) is one the few animal fats to be solid rather than oil.  **Phospholipids** - Consists of glycerol with long chain FA and Phosphoric acid, and nitrogen base. - Essential component of animal cell membrane and lipid transport in plasma, and for digestion of fats. Phospholipid --- Structure & Function - Expii **Steroids** - Still hydrocarbon, but instead of being linear molecules, these include ring-shaped molecules. - Include cholesterol, testosterone (male sex hormone),estrogen and progesterone (female sex hormones). - Used in animals as hormones (chemical signals), also in membrane structure.