| Date | May 2018 | Marks available | 6 | Reference code | 18M.3.HL.TZ1.13 |
| Level | Higher level | Paper | Paper 3 | Time zone | Time zone 1 |
| Command term | Explain | Question number | 13 | Adapted from | N/A |
Question
Explain the process of gene therapy using viral vectors.
Markscheme
a. used on genetic diseases caused by defective genes/lack of enzyme/ protein
b. viral vector (genetically) modified for (safe) use
c. virus genome is altered and missing gene/allele is introduced into virus
d. a retrovirus is used to introduce RNA and reverse transcriptase in a host cell
e. RNA is copied into DNA and introduced (permanently) into the cells genome
f. could use adenovirus/virus with DNA to introduce genetic material
g. in this technique DNA is not attached to cell genome
h. thus not replicated during host cell replication / treatment has to be repeated
i. it could be done in somatic treatment (body cells) or in sex cells (egg cells)
j. example (ie Gendicine, is an adenovirus used for treatment of head and neck cancer)
