*Polymers and Life

• Peptide bonds are formed between the N and C on an amino acid that releases a H2O molecule to form a dipeptide
• When acid hydrolysis occurs the NH2 becomes NH3+ as it accepts a proton and acts as a base
• A dislufide bond is when two S-H groups bond to form S-S and lose 2 hydrogens
• Nucleotides are formed by one sugar, a nitrogenous base and a phosphate group. DNA has a deoxyribose sugar and RNA has a ribose sugar
• Guanine and Cytosine form 3 hydrogen bonds while Adenine and Thymine form two hydrogen bonds
• A pharmacophore is the part of a molecule that has a particular pharmecutical or biological function
• Rf values = distance travelled by component/distance travelled by solvent front
• Carboxylic acids are weak and therefore react with bases in neutralisation reactions to produce a salt

  e.g. CH3COOH + NaOH -> CH3COONa + H2O
• metal + carboxylic acid -> salt + hydrogen
• metal carbonate + carboxylic acid -> salt + carbon dioxide + water
• Zwitterions are a molecule that contains two functional groups that can behave as either acids or bases, like amino acids
• Amino acids are zwitterions as the amine group can have a positive charge (NH3+) and the carboxyl group can have a negative charge (COO-)
• Acyl chlorides have a functional group COCl and the suffic -oyl chloride
• Nylon is a polymer made from a diamine and dicarboxylic acids or by a diamine and diacyl chloride joined by amide linkages
• Nylon 6,6 is 6 carbons on both the amine and carboxylic acid/acyl chloide
• Nylon 6,10 is 6 carbon amine and 10 carboxylicacid/acyl chloride
• Nylon 6 is made of one monomer which contains both the amine and carboxylic acid/acyl chloride that's 6 carbons long
• Hydrolysis of esters is the reverse to esterification and uses water to split the molecule
• Ester hydrolysis can occur in acidic conditions which contains an aqueous acid and heat to produce carboxylic acid and alcohol
• Ester hydrolysis can occur in alkaline conditions which contains an aqueous alkali and heat to produce a carboxylate salt and an alcohol
• Acyl chloride reactions:

  • x + alcohol -> ester
  • x + ammonia -> amide
  • x + amines -> N-substituted amide
• Acyl chlorides react via nucleophilic addition-elimination reactions as the addition of a nucleophile leads to elimination of a product
• Acyl chloride nucleophili addition-elimination reaction:

  1. C=O bond donates pair of electrons to O so carbocation is formed
  2. NH3 lone pair attracted and bonds with the carbocation
  3. H on NH3 donates electron to NH2 and is released, chloride atom accepts electron from carbon to become chloride ion
  4. Oxygen donates electron to carbon to reform double bond
  5. HCl is waste product
• Condensation polymerisation is formed when monomer contains functional group that's involved in bonding and releases small molecules
• A chiral carbon is a carbon that is bonded to four different groups and no symmetry
• Chrial carbons lead to two possible isomers that are non-superimposable (optical isomers)
• The two different isomers are called enantiomers and are unique due to their effect on plane of polarised light as each enantiomer rotates plane polarised light in different directions