| Date | November 2017 | Marks available | 3 | Reference code | 17N.3.SL.TZ0.09 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Explain | Question number | 09 | Adapted from | N/A |
Question
Tobacco mosaic virus (TMV) was used as a vector in the development of a new process for Hepatitis B vaccine production.
[Source: Scholthof, K-B.G. 2000. Tobacco mosaic virus. The Plant Health Instructor. DOI: 10.1094/PHI-I-2000-1010-01. Updated 2005. © 2018 The American Phytopathological Society. All rights reserved.]
State the role of a vector in biotechnology.
Explain how the Hepatitis B vaccine is produced using TMV.
State the importance of marker genes in genetic modification.
Markscheme
carries/transfers genetic material into a cell
a. TMV contains RNA/is a retrovirus
b. gene of hepatitis B «virus» codes for antigen
OR
hepatitis B «virus» has a gene that induces an immune response
c. «antigen» fuses to capsid gene for TMV
d. two fused genes enter/infect the plant cells «using the virus as a vector»
e. mice fed with infected plants produce antibodies against hepatitis B
f. antibodies are extracted from mouse serum/blood
Allow other mammal
[Max 3 Marks]
marker genes show the «target» gene has been inserted
