DP Chemistry (last assessment 2024)
Question 23M.3.HL.TZ1.18
| Date | May 2023 | Marks available | [Maximum mark: 4] | Reference code | 23M.3.HL.TZ1.18 |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Explain, Suggest | Question number | 18 | Adapted from | N/A |
18.
[Maximum mark: 4]
23M.3.HL.TZ1.18
Many illnesses are caused by bacteria and viruses.
(a)
Explain two ways antiviral medications prevent the replication of viruses.
[2]
Markscheme
Any two of:
«bind to receptors to» prevent virus entering cell ✓
alter genetic material of cell/cytoplasm «to prevent replication» ✓
block enzyme activity in cell «to prevent replication» ✓
prevent virus leaving cell «by inhibiting viral enzyme/neuraminidase» ✓
(b)
Bacterial infections are treated using antibiotics such as penicillin. Suggest how penicillin can be modified and the reasons for the modification.
[2]
Markscheme
side chain modified ✓
overcome antibiotic resistance/ penicillinase ineffective ✓
Accept R group instead of side chain.
Accept increase the stability of penicillin in GIT/gastrointestinal tract for M2.