Viruses (Cambridge (CIE) O Level Biology): Revision Note

Viruses

• Viruses are not part of any classification system as they are not considered living things

• They do not carry out the seven life processes for themselves, instead they take over a host cell’s metabolic pathways in order to make multiple copies of themselves

• Virus structure is simply

  • Genetic material (RNA or DNA)

  • A protein coat

  • Some viruses contain an outer envelope as shown in the image below

• As a result, they can only replicate inside living cells

Structure of a virus diagram

Structure of a typical virus

• The structures of viruses can be varied, but all contain the same basic elements of a protein coat and genetic material

Virus Diagram