Question

Draw an. ionized version of an amino acid and label the major parts(N terminus, C-terminus, alpha-carbon, backbone) of the molecule.

Specifically describe how an amino acid is affected by different pH’s (<7, 7, >7).

Which form is most common and why/how is that important for cell function/survivability?

Answer 1

The carbon to which carboxyl group is attached is called alpha carbon. The amino group is called the N terminus while carboxyl group end is called the C terminus.

The R group( side chain) is different in different amino acids.

When dissolved in water (at ph7/ neutral pH) it exists as zwitter ion as dipolar ion. It has both positive and negative charge. A zwitter ion can act as both acid and base. So, it is a amphoteric molecule. At low pH ( less than 7) the carboxyl group accepts a proton so overall charge become positive due to charge on the amino group. Similarly, at higher pH the amino group loses a proton and become uncharged, this overall charge becomes negative.