POLYMERS OF LIFE OCR B A-LEVEL CHEMISTRY.

describe the general structure of amino acids

describe proteins as condensation polymers formed from amino acid monomers (including the hydrolysis of peptides)

Hydrolysis of peptides: the peptide link in proteins can be hydrolysed to release individual amino acids, peptides are secondary amides and hydrolysis can be carried out by heating with moderately concentrated acid or alkali. The breakdown of proteins is routinely carried out by boiling with moderately concentrated hydrochloric acid to hydrolyse the amide C-N bonds; this is usually catalysed by enzymes in living organisms than by acid or alkali. Paper chromatography can be used to identify the individual amino acids present in a peptide. The petite is hydrolysed under reflux and the product is compared to known samples of pure amino acids using chromatography.

describe paper chromatography

describe the primary structure of proteins

the order of amino acid residues

describe the secondary stricture of proteins

the coiling of parts of the chain into a helix or the formation of a region of a sheet.

describe the tertiary structure of proteins

the folding of a secondary structure.

explain the role of intermolecular bonds in determining the secondary and tertiary structures and hence the properties of proteins

explain the phosphate units join by condensation with deoxyribose or ribose to form the phosphate–sugar backbone in DNA and RNA

what are the four bases present in DNA and RNA join by condensation with the deoxyribose or ribose in the phosphate–sugar backbone

These bases are Adenine, Thiamine, Cytosine, and Guanine.

explain how two strands of DNA form a double-helix structure through base pairing

the significance of hydrogen bonding in the pairing of bases in DNA and relation to the replication of genetic information; how DNA encodes for RNA which codes for an amino acid sequence in a protein

describe the pharmacophore and groups that modify it, its interaction with receptor sites, the ways that species interact in three dimensions (size, shape, bond formation, orientation)

describe the shape of the rate versus substrate concentration curve for an enzyme-catalysed reaction.

describe specificity in terms of enzyme catalysis

describe temperature in terms of enzyme catalysis

continued..... Some of the tertiary structure bonds are weak dipole-dipole bonds and hydrogen bonds. These can be broken easily by raising the temperature, which causes them to vibrate more vigorously and weaken or break.

At higher temperatures, the enzyme is denatured and the activity falls.

describe pH in terms of enzyme catalysis

describe inhibition in terms of enzyme catalysis

explanation of these characteristics of enzyme catalysis in terms of a three-dimensional active site (part of the tertiary structure)

the acidic nature of carboxylic acids, and their reaction with metals, alkalis and carbonates

The salt formed is calcium ethanoate.

the acidic nature of carboxylic acids, and their reaction with metals, alkalis and carbonates (continued).

describe the acid-base properties of amino acids and their existence as zwitterions