Polymers of life Flashcards
Amino acids can exist as Zwitterions. What is a zwitterion?
Where the overall charge of the molecule is zero / neutral but both a positive and negative charge exist on different parts of the molecule.
A Zwitterion can only exist at an amino acids…..?
Isoelectric point.
What is an isoelectric point ?
The pH where the overall charge on the molecule is neutral / zero.
If the conditions are more acidic than the isoelectric point, what happens ?
The NH2 group is protonated to NH3+.
If the conditions are at the isoelectric point, what happens?
Zwitterion is formed.
If the conditions are more alkaline / basic than the isoelectric point, what happens ?
COOH will lose it’s proton to form COO-.
What are proteins?
Condensation polymers of amino acids.
What are the monomers in proteins joined by?
Peptide links / bonds.
The product of two peptides / amino acids polymerising is called:
Dipeptide.
What is condensed out when amino acids join to make a polymer?
H20 ( water ).
What is the peptide bond / link in dipeptides formed between ?
The C on the COOH of one amino acid and the N on the NH2 of another amino acid.
What are the conditions required to perform hydrolysis on a protein to reform it’s original amino acids ?
Hot aqueous Hydrochloric acid of concentration 6mol/dm3, heated under reflux for 24 hours, which produces ammonium salts of the acids that then need to be neutralised using a base.
How many different levels of structure do proteins have and what are they ?
3 : primary, secondary and tertiary.
What is the primary structure of a protein?
The sequence of amino acids / polypeptide chain.
