MCAT Biochemistry

• Has an amino group and an carboxly group 
• -Nh2 -COOH
• 20 proteinogenic

A sequence of 3 nucleotide that form a unit of genetic code in DNA or RNa molecules.

The metabolic process by which the body expels excess nitrogen.

haveing four different groups attached to it.

h is the fr group and it is the only achiral amino acids

• all amino acids in eurklaryotes like you and I are like you and I are L-amino aids. L for living.
• Thus the aminogroup is drawn on the left for a fisher projection

This is the only L-amino acid with an R absolute configuration

non aromatic. can be a ring structure but cannot have alternating double bonds like the typical aromatic ring

• kinky amino acid 
• forms a five-membered ring with the amino group
• limited flexibility and which limits where it can appear in a protein

• The ph at which half of the the molecules in a species is protonated and the other half is deprotonated
• [HA]=[A-]

• when the ph is lower than the pKa the species tend to to be protanted for the majority 
• and vice versa

• acid ionization constant 
• this measures the strength of an acid

• Histidine 
• Aspartic acid
• and serine

having the characteristics of both an acid and a base

• like a detergent:
• has both hydrophobic and hydrophillic groups.

• ionizable groups tend to be protonated in acid environment and deprotonated in basic environments.
• thus low ph means that the ionizable group is protonated and at high pH it is deprotonated.