Polymers, Proteins and Amino acids

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Amino acids

They are mostly chiral which means that they will rotate plane polarised light as they form to enatiometers which are nonsuperimposable mirror images of one another.The results is optically inactive as it will be a racemic mixture of the 2 isomers.

They are able have very high melting points because they are able to transfer electrons around the molecule to forma zwitterion ( an ion with two opposite charges , but has no overall charge) this leads to the formation of very strong ionic forces leading to the high metlting temperature.

With Nihydrin and a little heating amino acids chage colour to form purple/blue spots on a thin layar chromotography  sample sheet. Amino acids are the monomers of protiens whichare long chains of polypepetide which may have further layers of organisation such as secondary beta pleated sheets or alpha helixes , 3D structure in the form of tertiary structure and quarternanry structure which is the formation of complexed proteins which have more than one chain of amino aicds in tertiary structure. 

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Polymers can be formed in 2 ways addtion or condensation. Condensation is the removal of a small molecule such as H2O or HCl whereas addition involves the breaking of a double bond in an alkene to form a polymer.

Polymers have a number of uses such as drinks bottles and fleeces or bags that can be dossolved when put in washing machienes  so infected chlothing can be washed- this is how liqitabs work for washing machienes as well because the polymer is water soluble due to the high number of OH groups present.The one down side is that polyesters and non biodegradeable - there is no a natural enzyme that is able to break this type of bond.

Polymers can formed from diols, dicarboxylic acids and diacyl chlorides, and diamines too! These would all work by condensation reactions.

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More on Amino aicds

Amino acids are amphoteric this means that they can acts as buffers ( they do this in the blood). In a solution of Aicd amino aicds will form A positive ion ( NH3+) and in basic solutions they will form  a negative ion ( COO-) Only at the isoelectric point will the zwitterion be present in solution.

Amino aicds which are all together in a solution can all be seprated by thin layer chromatography  they are clolourless so to find where the Amino acid has gone to the sheets will be sprayed with ninhydrin to turn the amino aicds purple. To identify the Amino aicds all you need to do is wok out the Rf value. Thin layer chromatography works to indenfy amino acids because they have different attractions to the mobile phase ( the solvent) and the stationary phase which in this case is a powdered solid of silica gel.

Protein decomposition

This s done by refluxing in HCl to form positive ions and thn adding water to form the amino acids and H3O+

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