1. (a) Complete the diagram showing the basic chemical structure of an amino acid - Leaving Cert Home Economics - Question 1 - 2004

To complete the diagram of an amino acid, we need to include the following components around the central carbon (C):

1. Attach a hydrogen atom (H) to the central carbon.
2. Attach a carboxyl group (-COOH) to the central carbon.
3. Attach an amino group (-NH2) to the central carbon.
4. Attach a side chain (R) which varies among different amino acids.

The completed structure should look like this:

    H
    |
  R-C-COOH
    |
   NH2

This structure represents the general form of an amino acid, consisting of a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable side chain.