The mammalian sperm is covered by the plasma membrane all over . It is composed of the  parts
(i) Head - It consists of a haploid nucleus which is covered anteriorly by a cap called acrosome. The acrosome has many enzyme with helps the sperm to digest the wall around egg and fertilize it.
(ii) Neck forms the juncture between head and the middle piece.
(iii) Middle piece contains numerous mitochondria which provide energy for the motility of sperm.
(iv)Tail is the posterior-most part of sperm.