Amino Acids Flashcards
What are amino acids?
Molecules with both an amino group and a carboxyl group.
Why are amino acids amphoteric?
Their amino group is basic, and the carboxyl group acidic.
What will happen to an amino acid in an environment with low pH?
The nitrogen atoms will gain a hydrogen atom and will all become poisitively charged.
What will happen to an amino acid in an environment with high pH?
The carboxyl group will lose a hydrogen atom and become negatively charged.
What is a zwitterion?
A molecule with both positively and negatively charged ends.
What is a protein?
Condensation polymers of amino acids joined by peptide links.
What is the byproduct of condensation of amino acids?
Water.
What are the conditions needed to hydrolyse a protein?
Hot aqueous 6M hydrochloric acid, under reflux for 24hrs.
What does hydrolysis of a protein do?
Break down the peptide links to produce amino acids.
How can we separate amino acids?
Using paper chromatography.
How do we carry out paper chromatography?
1) Draw a pencil line at the bottom of some chromatography paper and put a concentrated spot of the mixture onto it.
2) Dip the bottom of the paper in a solvent.
3) The amino acids will move with the solvent at different rates.
4) You can identify each amino acid by looking at how far it moves compared to the solvent.
5) Ninhydrin solution must be sprayed on the paper for amino acids to show up (turns them from colourless to purple).
Why is hydrogen bonding in proteins important?
Proteins fold and twist, and hydrogen bonds between polar groups keep them in this shape. A protein’s 3D shape it vital to how it functions, because if it acts as an enzyme, only one shape will do the job.
