This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Amino acid which lacks chirality: 
Select and explain. 
A. Lysine, B. Leucine, C. Histidine, D. Glycine
D: Glycine
Answer: D: Glycine 
Explanation: All amino acids except glycine have four different groups attached to the alpha carbon. As a result, all amino acids have at least one asymmetric center (the alpha carbon). We call a compound with such an arrangement 'chiral. ' The two chiral forms of amino acids are called 'D' and 'L'.
The general formula for an amino acid is: