The mammalian sperm cell consists of a head, a midpiece and a tail. The head contains the nucleus with densely coiled chromatin fibres, surrounded anteriorly by an acrosome, which contains enzymes used for penetrating the female egg.
DNA is a negatively charged component so the amino acids most probably to combine with the DNA are going to exhibit a positive charge at pH 7. Thus, the likely amino acids would be Arginine, Histidine, and Lysine.
There are three amino acids, which possess basic side chains at neutral pH. These are lysine, arginine, and histidine. Their side chains comprise nitrogen and bear a resemblance to ammonia that is a base. Their pKa values are high enough that they seem to combine with protons, thus, attaining a positive charge in the process.
A Polypeptide chain is a sequence of amino acids that is the foundation for the basic structure of a protein