| Date | May 2012 | Marks available | 1 | Reference code | 12M.1.HL.TZ1.30 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Outline | Question number | 30 | Adapted from | N/A |
Question
What occurs during the light-independent reactions of photosynthesis?
A. ATP is produced.
B. Ribose reacts with carbon dioxide to form glucose.
C. Energy for the cycle is provided by the light-dependent reaction.
D. Darkness stimulates the conversion of glucose to starch.
Markscheme
C
Examiners report
Question 30 was answered relatively poorly. Many thought that ATP is produced during the light independent reactions of photosynthesis, perhaps through misreading the question as light dependent reactions. Even more candidates thought that ribose reacts with carbon dioxide during the light independent reactions. Perhaps these candidates were thinking that the abbreviation RuBP means ribose bisphosphate, rather than ribulose bisphosphate. In assessment statement 8.2.5, the name of this chemical is given in full in the teachers‟ note and the abbreviation in parentheses, so the full name should be taught. Abbreviations of chemical names can be very ambiguous and in most cases Higher Level students should be familiar with the full name, not just the abbreviation.
