DP Chemistry (last assessment 2024)
Question 19M.3.hl.TZ2.8a
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.hl.TZ2.8a |
| Level | hl | Paper | 3 | Time zone | TZ2 |
| Command term | Outline | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 1]
19M.3.hl.TZ2.8a
Heavy metals are toxic even in very low concentrations.
(a)
Outline why heavy metals are toxic.
[1]
Markscheme
Any one of:
disrupt endocrine system
OR
compete for active sites of enzymes/cellular receptors
OR
form complexes with/inhibit enzymes
OR
denature proteins
OR
change shape of active site [✔]
participate in redox reactions
OR
disturb normal redox balance «in cells» [✔]
initiate «free» radical reactions «in electron transfer» [✔]
Examiners report
The candidates seemed to have difficulty in outlining why heavy metals are toxic.
