the side chain for valine is classified as a
Valine Valine (symbol Val or V[3]) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain isopropyl group, making it a non-polar aliphatic amino acid. It is essential in humans, meaning the body cannot synthesize it: it must be obtained from the diet. Human dietary sources are foods that contain protein, such as meats, dairy products, soy products, beans and legumes. In the genetic code it is encoded by all codons starting with GU, namely GUU, GUC, GUA, and GUG.
Flank (anatomy) The flank or latus is the side of the body between the rib cage and the iliac bone of the hip (below the rib cage and above the ilium).[1]