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Lipids: they're function and biological significance

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Lipids: they're function and biological significance Lipids are biological molecules and are insoluble in aqueous solutions but are soluble in organic solvents. Specific lipids have a physiological importance to humans; they have three major functions; serving as structural components of biological membranes, act as vitamins and hormones, provide energy storage (triaculglycerols). Lipids are made up of the elements carbon, hydrogen and oxygen. Lipids can exist as fats, oils and waxes. Fat and oils are similar in structure as they are triglycerides, however, they physically differ at room temperature fats are solid and oils liquid. Their differences in property are what help contribute to its significance in life. A triglyceride consists of fatty acid chains which are attached to a glycerol molecule; fatty acids are chains of carbon atoms, the first carbon atom is attached to an OOH group resulting in a carboxylic group (COOH). The normal length of the chain is roughly 14 to 22 carbons long, with the most common chains being between 16 and 18 carbons long. Triglycerides can occur with two types of bonding. Saturated triglycerides have no double bonds between the carbon and the hydrogen. ...read more.


This is due to fat conducting heat very slowly; consequently having a layer under the skin insulates metabolic heat in. Oils are a major energy store in seeds and industrially are extracted for human use. The bonds between the fatty acid chains are what make them different. The three fatty acids could be identical or not, a fatty acid may have single bonds making it a saturated lipid. These are more commonly known as fats and are solid at room temperature. Lipids can also occur as waxes or steroids depending on the structure of the lipid as well as the amount of fatty acids and glycerol's. Triglycerides consist of 3 fatty acid chains and 1 glycerol molecule; this is the resultant of a condensation reaction. They appear to be macromolecules due to the hydrophobic behaviour resulting in the small molecules clumping together. Lipids are also significant in electrical insulation within humans. The myelin sheath around the axons of neutrons act as electrical insulators to the cells' plasma membrane ensuring the nerve impulse can pass down the axon. Phospholipids are important within cells and have a similar structure to triglycerides. ...read more.


Oestrogen requires lipids for its formation, as do other substances such as plant growth hormones. Cholesterol, however, as is widely known can be harmful in excess and can form atherosclerosis (a condition in which fatty material is deposited along the walls of arteries. This fatty material thickens, hardens, and may eventually block the arteries). Just as other lipids cholesterol is insoluble so is carried to sites where it is metabolised or stored via the blood plasma combined wit soluble proteins. Waxes are, finally, the other form of lipids. They are esters formed from a fatty acid and a complex alcohol. These are produced by plants and help to limit water loss through evaporation, as form a waxy cuticle. Wax is secreted by insects for the same role on the outer surface of their cuticle. Bees use wax in the honeycomb cells they build for rearing their larvae and storing honey. Conclusively lipids are highly significant in many life processes. The creation of lipids allows both plant and animal life to carry out vital functions in order to maintain life. Without lipids our bodies would be polluted from cells being invaded by substances that shouldn't enter and thus is an extremely important component for the sustenance of life. ?? ?? ?? ?? Keshan Bolaky ...read more.

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