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20 Cards in this Set
- Front
- Back
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What is the general formula for an alpha amino acid?
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RCH(NH₂)COOH
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When does an amino acid exist as a zwitterion?
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At the isoelectric point
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How is an amino acid's isoelectric point determined?
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By the R group on the amino acid
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How do you form a peptide (amide) linkage?
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By condensation (and subsequent condensation polymerisation) to form polypeptides and proteins.
NB: A polypeptide is one containing more than ten amino acids (normally 100-300) |
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What happens in acid hydrolysis of proteins? What is formed? What would happen in alkaline conditions?
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It is split up into its constituent amino acids. This is called 'acid-catalysed hydrolysis'. The terminal amine group (-NH₂) accepts a proton to become -NH₃⁺. Alkaline conditions form a carboxylate.
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Define optical isomerism
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Non-superimposable mirror images about an organic chiral centre: four different groups attached to a carbon atom.
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Optical and E/Z isomerism are due to different types of _______________
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stereoisomerism.
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List two polyamides
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Nylon-6,6 and Kevlar
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List two polyesters
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Terylene and Poly(lactic acid)
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What are some uses of polyesters and polyamides?
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Fibres in clothing
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Acid hydrolysis of polymers produces the constituent monomers, what about alkaline?
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The salts. CH₃COO⁻, for example.
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Which type of polymers may be photodegradable? Why?
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Polymers with the carbonyl (C=O) bond, because the bond can adsorb radiation.
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What is an example of the use of naturally biodegradable polyesters?
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Poly(lactic acid) is used in medical stitches
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How can environmental waste be minimised?
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By incorporating the C-O bond into the polymer chain.
By hydrolysing ester and amide bonds Produce polymers formed from plant feedstock (see page 25 of revision guide for ads/disads) |
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Where would condensation polymers be hydrolysed?
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Ester/amide group
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The synthesis of pharmaceuticals often requires the production of...
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a single optical isomer
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Synthetic molecules often have a _______ of optical isomers while natural production has...
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mixture
...a single optical isomers |
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Why does synthesis of a pharmaceutical that is a single optical isomer increase costs?
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There is difficulty in separating the optical isomers
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What are the benefits of separating optical isomers?
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Reduces side effects and IMPROVES PHARMACOLOGICAL ACTIVITY
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What are the ways of synthesising a pharmaceutical with a single optical isomer?
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Using enzymes or bacteria which promote STEREOSELECTIVITY
Using chemical chiral synthesis or CHIRAL CATALYSTS Use natural chiral molecules, such as L-amino acids or sugars AS STARTING MATERIALS |
