2. Proteins Flashcards
What are proteins made of?
Amino acids are monomers from which polymer proteins are made.
What groups does an amino acid contain?
Amine group (NH3) , a carboxyl group (COOH) and R ( representing a variable group.
How are dipeptides formed?
By condensation of two amino acids between one amine and one carboxyl group forming a peptide bond.
What are polypeptides?
Polypeptides are polymers formed by the condensation of many amino acids joined together by peptide bonds.
What is the primary structure of a protein?
The number and sequence of amino acids in a polypeptide chain formed by peptide bonds
What is the secondary structure of a protein?
Formed by hydrogen bonding between the carboxyl and amino groups in the peptide backbone of amino acids forming alpha helixes and beta pleated sheets
What is the tertiary structure?
Further folding , Formed by the interaction between the R group on amino acids which form hydrophobic interactions, ionic bonding, hydrogen bonding and disulphide bonding.
What is the quaternary structure of protein?
Proteins which contain more than one polypeptide chain
What is the test for protein?
Biuret reagent. Change to purple/lilac
How do proteins usually function?
Usually function due to the shape of their active sites which are complementary to the structure of another molecule
How is the tertiary structure of a protein determined?
Sequence of amino acids in a primary structure
Position of R group
Formation of hydrogen and ionic bond.
How can you separate proteins using paper chromatography?
Set up with spot of unknown amino acid placed on line. Lower into solvent. Diff amino acids have diff solubility so travel diff distances depending on charge and size. Dry and spray with ninhydrin solution, compare to known standards.
How are proteins/ amino acids separated using gel electrophoresis?
seperate based on size/mass and charge of protein.
What are example of quaternary structure?
Antibodies (4 amino acids held by disulphide bonds) and haemoglobin.
What are disulphide bridges?
Bonds between 2 sulfars in amino acids and are similar to covalent bonds.
