Final answer:
Capsids are made of protein subunits called capsomeres, which are held together by non-covalent interactions rather than covalent bonds. Capsid shapes can vary, and some viruses also have an external envelope that helps them infect host cells.
Step-by-step explanation:
The statement that capsids are made of a number of capsomeres which are covalently bonded to one another is false. Capsids are indeed made up of protein subunits called capsomeres, but these subunits are not covalently bonded. Instead, they are held together through non-covalent interactions such as hydrogen bonding, ionic interactions, and protein-protein interactions. These capsomeres self-assemble to form the closely packed capsid that shields the viral nucleic acid. Capsids can have a variety of shapes, being helical, icosahedral, or more complex structures. Some viruses also have an external envelope, which is derived from portions of the host cell's membrane and can aid the virus in evading the host's immune system and facilitating attachment and entry into host cells.