Topic 4: Amino Acids

Question 1

Difference between alpha and beta amino acid

Answer 1

In alpha amino acids, the amino and carboxyl group are bonded to the alpha carbon, while in beta amino acids, the carboxyl is bonded to the alpha carbon, and the amino group is one carbon away, on the beta carbon

Question 2

All mnemonics used for amino acids

Answer 2

Glaciers in Alaska Valianty Locate Isolated Prowlers (Non-polar/hydrophobic amino acids): Glycine, alanine, valine, leucine, isoleucine, proline

Ppl go to alaska because the aroma of fine pine and yellow timber are worth the tryp
(3/4 of the aromatic amino acids), weird single letter codes: Phenylaniline, tyrosine and tryptophan

Alcohol is a serious threat
(2 alcohol amino acids): Serine and threonine

Basically, his kid always returned
(3 basic amino acids, weird single letter code for last two): Histidine (also aromatic), Lysine, Arginine

Methodically check the path for sulfur
(2 sulfur amino acids): Methionine and Cysteine)

As peter digested the glue, his stomach became acidic
(2 acidic amino acids, weird single letter codes): Apartic acid/aspartame and glulatmic acid/glutamate

As peter digested the glue, his stomach become acidic (just reusing it because the last two are amide analogues of aspartic acid and glutamic acid)
(2 amide amino acids: Asparagine and glutamine)

Question 3

Important properties of amino acids

Answer 3

Polymerize
Contain acid-base properties
Varied structure and functionality
Chiral
Zwitterions
High melting points

Question 4

Define the pI

Answer 4

The pH where the zwitterion dominates in solution, where the majority of molecules in solution have no net charge

Question 5

How to calculate pI of an amino acid

Answer 5

Draw a number line of the pH scale and using a table of pkas for the ionizable groups, find the pKa where the amino acid would exist as a zwitterion, while drawing the structures of the amino acid at the other pKas , and take the average its neutral pKa the side chain pKa