1.4.1 Proteins Flashcards
Describe an amino acid
A central carbon with a single Hydrogen, an amine group, a carboxyl group, an R side chain. The twenty amino acids that are common in all organisms differ only in their R side group.
A condensation reaction between amino acids results in…
A condensation reaction between two amino acids forms a peptide bond.
Dipeptides are formed by the condensation of two amino acids.
Polypeptides are formed by the condensation of many amino acids.
Water is eliminated with each condensation reaction, through the loss of a hydrogen from the amine group of one amino acid, and the OH of the carboxyl of the other amino acid.
Primary structure of a protein…
Sequence of amino acids joined by peptide bonds.
Secondary structure of a protein…
Hydrogen bonding between NH (group of one amino acid) and C=O (group) of another, forming β pleated sheets / α helix.
Tertiary structure of a protein…
Tertiary structure is 3-D folding due to hydrogen bonding and ionic / disulfide bonds between R groups.
Quaternary structure of a protein…
Quaternary structure is two or more polypeptide chains together in the same functional protein
Describe a biochemical test to confirm the presence of protein in a solution.
1. Add biuret (reagent);
Accept sodium hydroxide (solution) and copper sulphate (solution)
2. (Positive result) purple/lilac/violet /mauve;
Ignore references to heating
