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.
About 9 amino acids have non-polar R-groups and are relatively hydrophobic. Another 6 amino acids have strongly polar R-groups which readily attract water molecules. These are hydrophilic amino acids. The remainder, about 5 amino acids, have R-groups which can ionize. At normal cellular pH's these R-groups become electrically charged, making them even more hydrophilic than the polar amino acids. Any of the 20 different amino acids can occur in any position along a polypeptide chain.