Question 18M.2.SL.TZ2.5b
| Date | May 2018 | Marks available | [Maximum mark: 4] | Reference code | 18M.2.SL.TZ2.5b |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Describe | Question number | b | Adapted from | N/A |
Every cell is surrounded by a cell surface membrane which regulates the movement of materials into and out of the cell.
Describe the processes involved in absorbing different nutrients across the cell membrane of villus epithelium cells lining the small intestine.
[4]
a. «simple» diffusion of nutrients along/down a concentration gradient
b. example of simple diffusion, eg: fatty acids
c. facilitated diffusion of nutrients involves movement through channel proteins
d. example of nutrient for facilitated diffusion eg: fructose
e. active transport of nutrients against a concentration gradient / involving protein pumps
f. example of active transport, eg: (iron) ions/glucose/amino acids
g. endocytosis / by means of vesicles
h. example of nutrient for endocytosis, eg: cholesterol in lipoprotein particles
