DP Biology (last assessment 2024)
Question 18M.2.SL.TZ2.a
Date | May 2018 | Marks available | [Maximum mark: 4] | Reference code | 18M.2.SL.TZ2.a |
Level | SL | Paper | 2 | Time zone | TZ2 |
Command term | Draw | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 4]
18M.2.SL.TZ2.a
Every cell is surrounded by a cell surface membrane which regulates the movement of materials into and out of the cell.
Draw an annotated diagram of the fluid mosaic model of membrane structure.
[4]
Markscheme
a. phospholipid bilayer – with head and tails
b. hydrophilic/phosphate/polar heads AND hydrophobic/hydrocarbon/fattyacid/non-polar tails labelled. Both needed.
c. integral/intrinsic protein – embedded in the phospholipid bilayer
d. protein channel – integral protein showing clear channel/pore
e. peripheral/extrinsic protein – on the surface
f. glycoprotein with carbohydrate attached
g. cholesterol – shown embedded in bilayer
Award [1] for each structure clearly drawn and correctly labelled.
