Date | November 2018 | Marks available | 2 | Reference code | 18N.3.SL.TZ0.18 |
Level | Standard level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
Command term | Explain | Question number | 18 | Adapted from | N/A |
Question
The image shows a section through the ileum as viewed under the light microscope.
On the diagram, label the epithelial cell layer.
Explain how the epithelial cells are adapted for absorption.
Markscheme
arrow pointing at an epithelial cell ✔
Accept a bracket label to show the epithelium epithelial cell layer
a. microvilli/brush border to increase surface area ✔
b. numerous mitochondria for energy for active transport ✔
c. have transport proteins for specific nutrients ✔
d. single layer of cells/short distance allowing for diffusion ✔
Explanation must be included for each characteristic eg: “glucose, amino acids”