| Date | November 2013 | Marks available | 1 | Reference code | 13N.1.HL.TZ0.36 |
| Level | Higher level | Paper | Paper 1 | Time zone | TZ0 |
| Command term | Question number | 36 | Adapted from | N/A |
Question
How are B-cells activated?
A. An antibody binds to a B-cell which is activated by a helper T-cell.
B. An antigen binds to a B-cell which is activated by a helper T-cell.
C. An unattached antigen binds to a helper T-cell which activates the B-cell.
D. An antibody binds to a plasma cell which is activated by a helper T-cell.
Markscheme
B
Examiners report
This raised a few comments on the G2 forms. The correct answer of B was only given by half the number of the candidates who gave the incorrect answer of C. It was decided that the wording was perhaps too subtle and in the end both B and C were deemed worthy of the mark.
