| Date | May 2009 | Marks available | 1 | Reference code | 09M.1.HL.TZ1.20 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 20 | Adapted from | N/A |
Question
Why are antibiotics effective against bacteria but not viruses?
A. Viruses can hide inside host cells.
B. Bacteria are recognized as pathogens but viruses are not.
C. The enzymes of bacteria can be inhibited by antibiotics.
D. Viruses are resistant to antibiotics.
Markscheme
C
Examiners report
Many candidates thought that antibiotics are not effective against viruses because these can hide inside the host cell, failing to acknowledge the effect of antibiotics on bacterial enzymes.
