The average estimated cash rent was $202 per acre on top quality land, $161 per acre on average quality land, and $124 per acre on poor quality land. This was an increase in rental rates of 2.0% for top quality land, 1.9% for average quality land, and 2.5% for poor quality land.
R-Group. In solution it is the nature of the amino acid R-groups that dictate structure-function relationships of peptides and proteins.
The carboxyl group, along with the amino group, allows amino acids to be zwitterions where both the amino group and the carboxyl group are charged. Since the carboxyl group can be deprotonated, it can impart a negative charge onto the amino acid. The carboxyl group is also key in the formation of peptide bonds.