Phages usually have complex capsids (protein coats) composed of a polyhedral head, containing the nucleic acid (DNA or RNA), and a helical tail, through which nucleic acid is injected into the host.

• 噬菌体通常由复杂的衣壳组成一个多角体的头部，包含有核酸（DNA或RNA）和螺旋状的尾管，通过这个尾管核酸可以被注入寄主的体内。