Proteins Flashcards
What is the general structure of an amino acid?
R group above
H2N—— C —— COOH
H atom below
How many amino acids are there?
20
What is the amine group?
NH2
What is the carboxyl group?
COOH
What makes amino acids different from each other?
Different R group
Outline the biuret test
protein test
1. Sample in a test tube with equal volume of NaOH
2. Add dilute copper sulfate and mix.
Positive result = blue—>purple
What is the primary structure of a protein?
Sequence of amino acids in a polypeptide chain.
Determined by sequence of bases in genes.
It determines the shape and function of the protein.
What is the secondary structure of a protein?
Polypeptide chain coils into an alpha helix or folds into a beta pleated sheet.
Hydrogen bonds are formed between amine and carboxyl groups.
What is the tertiary structure of a protein?
Structures of the secondary structure fold or coil more forming a 3D shape.
Held in place by hydrogen bonds, ionic bonds and disulfide bridges.
What is the quaternary structure of a protein?
Multiple different polypeptide chains joined together.
Can have non protein groups
e.g. Haemoglobin is associated with Fe2+
What is the name of the bond between two amino acids and where does this form?
-Condensation reaction occurs
-Peptide bond forms between carboxyl and amine
What is the equation to calculate pH?
pH = - log [H+]
