State two ways in which viruses are different from bacteria.

Describe two ways in which antiviral drugs work.

bacteria are a single cell / viruses are not cellular;

bacteria have cell walls/nuclei / viruses have no nucleus/cell wall;

bacteria larger than viruses / viruses smaller than bacteria;

viruses need host cell to reproduce / viruses take over another cell;

bacteria are organisms/living / bacteria metabolise/can grow/feed/excrete /

viruses are not living / viruses do not metabolise/grow/feed/excrete;

Allow “bacteria have both DNA and RNA / viruses have either RNA or DNA only (but not both)”.

alter cell’s genetic material;

block enzyme activity within host cell;

(changes cell membrane so that it) inhibits virus entry/bonding to cell;

prevents virus from leaving cell (after reproduction);

becomes part of DNA of virus / alters virus / blocks enzyme (polymerase) which builds DNA;

prevents virus from using cell to multiply/reproduce/replicate / prevents virus from using cell’s metabolism;

This question proved to be a life-line for candidates with a strong knowledge of biology and in both parts many candidates scored full marks. Many candidates gave overly lengthy answers here and more concise answers could easily have been given such as bacteria are larger than viruses and bacteria have cell walls unlike viruses in part (a).

This question proved to be a life-line for candidates with a strong knowledge of biology and in both parts many candidates scored full marks. Many candidates gave overly lengthy answers here and more concise answers could easily have been given such as bacteria are larger than viruses and bacteria have cell walls unlike viruses in part (a).