Question 21N.2.HL.TZ0.b
| Date | November 2021 | Marks available | [Maximum mark: 7] | Reference code | 21N.2.HL.TZ0.b |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Explain | Question number | b | Adapted from | N/A |
Explain the production of antibodies in humans.
[7]
a. antigens stimulate antibody production;
b. antibodies produced by lymphocytes;
c. macrophages/phagocytes ingest/engulf pathogens and display antigens from them;
d. T-cells activated by binding antigen/by macrophage displaying antigen;
e. activated T-cells cause activation of B-cells;
f. mitosis/division of (activated) B-cells (to produce a clone of cells)
g. plasma cells formed from divided/activated/growing/differentiating B-cells;
h. plasma cells/plasma B-cells secrete antibodies;
i. clonal selection / plasma cells make same type of antibody/antibody specific to same antigen;
j. some activated B-cells become memory cells;
This was another question giving scope to candidates to show the breadth of their biological understanding. The best answers were impressive but given the challenging nature of the topic it isn’t surprising that there were also some very muddled accounts. The weakest candidates struggled to remember the differences between antigens, antibodies and lymphocytes.
