Polypeptides (proteins) Flashcards
what is a polypeptide
a chain of amino acids
what two functional groups do amino acid monomers contain
amino and carboxyl group
How many different R groups are there
20
what is a dipeptide
2 amino acids
how is a dipeptide formed
a condensation reaction forms a peptide bond between the carboxyl group of one amino acid and the amine group of another. A water molecule is released in this reaction.
what reagent tests for protein
Biuret
what is biuret reagent
a solution of dilute sodium hydroxide and copper sulfate
what is the primary structure
the order/structure of amino acids (R-groups) in a polypeptide chain
what determines the primary structure
the order of nucleotides in a gene
what is the secondary structure
when hydrogen bonding between peptide bonds creates localised folding
what two structures can protein chains fold to
alpha helix, beta-plated sheet
where can the hydrogen bonds be found in protein folding
between the C=O and the H-N
name four types of amino R groups
-Ionic
-Cysteine (S)
-Hydrogen bonding (OH)
-Hydrophobic interactions (CH3)
what bonds do Cysteine R groups form and whats its name
Strong covalent bonds, called a disulphide bridge
what is tertiary structure
the precise 3D shape of a single polypeptide, stabilised by R-group interactions
