Date | May 2019 | Marks available | 3 | Reference code | 19M.3.HL.TZ1.10 |
Level | Higher level | Paper | Paper 3 | Time zone | Time zone 1 |
Command term | Explain | Question number | 10 | Adapted from | N/A |
Question
The diagram shows a spherical array of phospholipid molecules enclosing a water droplet. Such structures can be used to introduce genes into plant protoplasts.
[Source: SuperManu, https://en.wikipedia.org/wiki/Liposome#/media/File:Liposome_scheme-en.svg]
Explain briefly how plant protoplasts are prepared and how vesicles can be used to introduce genes into them.
Markscheme
a. enzymatically remove wall from plant cell to make protoplast ✔
b. use liposome ✔
c. get genes of choice into the vesicle/liposome ✔
d. get protoplast to fuse with the vesicle/liposome ✔
Examiners report
This question was not answered well by most candidates. Students struggled to explain concepts like how protoplasts are made, or the role of vesicles/liposomes.