Whats an Amino Acid?

Notes:

An amino acid is a building block of protein, and contains a carboxyl group, alpha carbon, and amino group. It is important to note that every time you see "R", it is referencing a variable "placeholder" for an amino acid group that is attached. 

Additionally, how they are depicted in terms of charge is how they would exist at pH of 7. Due to the bodies differing microenviornments, amino acids exist in vatious charged states throughout the body and cell. 

Amino acids also have a tendency to interact in different spaces depending on their "R" group. Some examples of polar vs nonpolar amino acids are shown above. As you can see, the amino acids on the left are nonpolar and consequently will be hydrophobic. Due to the folding capabilities of proteins, these amino acid residues will be found on the interior of a protein rather than the outside as it does not want to interact with an aqueous solution.