Summary Cell biology; chemical components of cells- Amino acids Review

Chemical components of cells: Amino acids

Amino acids are the building blocks of proteins

Structure of amino acid:

Amino terminus is a primary amide = N bonded to single C

Peptide bond has a secondary amide = N bonded to two C

Groups are available to accept and donate H bonds

Amides are organic N bound to carbonylm amines organic but
related to ammonia



Amide: N adajacent to a carbonyl, sexondary because only one H attached to the nitrogen

Condensation reaction in the ribosome – taking away water




20 common amino acids non-polar ‘R’ groups:

• Relatively unreactive side chains (no H-bonding)
• Hydrophobic side chains
• π-π stacking of aromatic rings
• Aromatic ring dipole can interact with polar groups

20 common amino acids polar ‘R’ groups:

• Reactive side chains
• Hydrophilic side chains
• Accept/donate H-bonds

20 common amino acids Charged ‘R’ groups:

• Salt bridges
• H-bonding
• Hydrophilic
• At physiological pH His not likely to be protonated
but may be dependent on local environment

Delocalised electrons generate weak charge in aromatic side chains