Structure and Function of Lipids

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  • Topic: Cholesterol, Fatty acid, Fat
  • Pages : 2 (806 words )
  • Download(s) : 168
  • Published : May 8, 2013
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Lipids are made up of carbon, hydrogen and oxygen (phospholipids also contain phosphate) and are found in a wide variety of organisms from bacteria to eukaryotes where they perform a wide variety of useful functions. This essay will expand on these functions to describe the role of lipids. There are several types of lipid including triglycerides, steroids, waxes and phospholipids. Triglycerides are made up of three fatty acids combined with glycerol by an ester linkage meaning they are predominantly hydrophobic. They are combined in a condensation reaction where water is released. Phospholipids and similar except one of the fatty acid tails is replaced by a charged phosphate group. This means phospholipids are made up of two parts as the phosphate head is hydrophilic while the tail is hydrophobic. This mean it is polar so when placed in water they position themselves so as the tail is as far away from the water as possible and the head is as close to the water as possible. However the distinct similarity between these two types of lipid is that they both have fatty acids chains that can either be saturated (carbon carbon single bonds) or unsaturated (at least 1 carbon -carbon double bond) Due to the chains without a double bond being able to pack more closely together they have a higher melting point than unsaturated fats. Steroids however have a different structure and are cyclic lipids with various side groups.  Cholesterol is an example of a steroid. It is important in the cell membrane as it stabilises it ensuring it does not become to like a fluid. If this were the case they would become too permeable to certain substances. However at the same time it prevents it becoming too rigid so cholesterol helps to prevent the cell membrane to maintain the correct consistency. However cholesterol is not the only lipid important for the plasma membrane, phospholipids are also essential. Due to their hydrophobic tails and hydrophilic heads they from a bilayer with the...
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