Chapter 3: Amino Acids

Hydroxyl properties

polar

Methyl Properties

non-polar

Carbonyl properties

polar

Carboxyl properties

acidic (releases H)

Amino properties

basic (accepts H)

Phosphate properties

acidic (releases H)

Sulfhyryl properties

polar

Each amino acid has four things…

amino group, carboxyl group, hydrogen, side chain (R-group)

Amino acids exist in the ___ and ___ forms

L and D

In acidic conditions, free amino acids are

both groups protonated

In neutral conditions, free amino acids are

dipolar ions (zwitterions)

In basic conditions, free amino acids are

both groups deprotonated

Non-polar R groups means that…

the amino acid is hydrophobic

Neutral R groups mean that…

the amino acid is polar with an unevenly distributed charge

Positively charged R groups mean that…

the amino acid is positively charged

Negatively charged R groups mean that…

the amino acid is negatively charged

Amino acids with hydrocarbon side chains are

hydrophobic

Amino acids with electronegative side chains are

polar

Amino acids with a negative charge have

acidic side chains

Positively charged amino acids have

basic side chains