Question 19M.2.HL.TZ2.2b.ii
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.2.HL.TZ2.2b.ii |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Suggest | Question number | b.ii | Adapted from | N/A |
DNA methylation has a critical role in gene regulation by affecting transcription. Samples were taken from two colon cancer tumours (T1 and T2) and two normal colon samples (N1 and N2). A particular gene was implicated as a possible cause of cancer. The promoter of this gene was cloned (A–J). The data show the DNA methylation patterns from these samples. The numbers (32–269) represent different markers in the promoter.
[Source: Philipp Schatz, Dimo Dietrich & Matthias Schuster. Rapid analysis of CpG methylation patterns using RNase T1
cleavage and MALDI-TOF. Nucleic Acids Research (2004) 32 (21): e167, doi:10.1093/nar/gnh165.
Reproduced by permission of Oxford University Press]
Suggest a way methylation may affect tumour cell genes.
[1]
a. «DNA» methylation may inhibit transcription of genes that would prevent cancer/tumor formation ✔
b. «DNA» methylation may increase mitosis/cell division leading to tumor formation ✔
Do not accept discussion of histone methylation.
Students lacked the understanding of epigenetics necessary to make reasonable suggestions.
