Bacteriophage's Morphology

1) All phage's have a nucleic acid core covered by a protein coat or capsid. The capsid is made up of  morphology subunits called CAPSOMERES. The capsomeres consist of number of protein subunits or molecules called PROMOTERS.
2) Bacterial viruses may be grouped into 6 morphological types :-
  A: This most complex type has a hexagonal head, a rigid tail with a contractile sheath and tail fibres
  B: Similar to A, this type has a hexagonal head however it lacks a contractile sheath, its tail is flexibly and it may or may not have tail fibres.
  C: This type is characterized by a hexagonal head and a tail shorter than the head. The tail has no contractile sheath and may or may not have tail fibres.
  D: This type has a head made up of large capsomeres but has no tail.
  E: This type has a head made up of small capsomeres but has no tail.
  F: This type is failamentous.
 3) Type A,B and C show a morphological unique to bacteria phage's. The morphological types in group D and E are found in plants and animals.
The filamentous form of group F is found in some plant viruses.
 4) Pleomorphic viruses were recently discovered to have a lipid- containing envelop have no detectable capsid and posses double-Stranded DNA.