Question 19M.2.SL.TZ1.7b
| Date | May 2019 | Marks available | [Maximum mark: 4] | Reference code | 19M.2.SL.TZ1.7b |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Describe | Question number | b | Adapted from | N/A |
Describe the functions of proteins in cell membranes.
[4]
a. facilitated diffusion by channel proteins ✔
b. active transport by protein pumps
OR
protein pumps eg sodium-potassium ✔
c. cell recognition by glycoproteins/protein receptors ✔
d. communication/receptors for hormones/signal molecules ✔
e. cell adhesion ✔
f. allow up to one additional mark for AHL material ✔
A wide variety of fairly well-developed answers. Often, they did not couple a type of protein with its function or missed marks by being too general. Saying “transport proteins” was not enough. Often the terms integral and peripheral proteins were mentioned without going beyond that. Channel proteins and facilitated diffusion was most commonly given. The mistaken idea that proteins offer structural support or strengthen the cell membrane was seen repeatedly.
