2018_Cancer_MCQ_QP+MS

2018 Cancer MCQ 2018 / H2 / ACJC PRELIM / P1 Q171Elephants have been found to be strangely resistant, though not immune, to cancer. They are four times less likely to develop cancer as compared to humans. Elephants have 40 copies of the p53 gene while humans only have two. In addition, three genes which code for DNA repair proteins have found to be very active.What do these observations suggest?AAll DNA mutations in the elephant are repaired.BWhen elephants develop cancer, it is due to environmental causative factors such as excessive exposure to UV light.CThe occurrence of cancer is due to the p53 oncogene, which stimulates the cell to divide rapidly, bypassing the cell cycle checkpoints.DThere is large amount of p53 proteins in an elephant cell which prevent cells with mutations from moving past the cell cycle checkpoints. 2018 / H2 / AJC PRELIM / P1 Q182mRNA was isolated from a normal individual and a patient suffering from cancer. The mRNA was allowed to hybridise with the p53 DNA gene sequence. The schematic diagram shows the results of the hybridisation process under the electron microscope. Which of the following could be a possible explanation why the patient is suffering from cancer?AA point mutation had occurred in the intron leading to the failure to excise one intron, resulting in a longer dysfunctional protein being produced.BGene amplification had occurred leading to the multiple copies of a trinucleotide repeat in an intron, hence causing splice site to be misread due to frameshift

mutation, resulting in a longer dysfunctional protein being produced.CA point mutation had occurred in the intron leading to the failure to excise one exon, resulting in a hyperactive protein being produced. DA point mutation had occurred leading to the failure of spliceosome to recognise splice sites, causing the excision of the wrong intron, resulting in a degradation-resistant protein being produced.2018 / H2 / DHS PRELIM / P1 Q83Which of the following statements about cancer are TRUE?1.Oncogenes and tumor suppressor genes can both be detected by introducing fragmented DNA from cancer cells into suitable cell lines and isolating colonies that display cancerous properties2.Individuals who inherit one inactive copy of tumour suppressor gene are more likely to develop cancer than individuals with two non-mutant copies3.Viruses and other infectious agents play no role in human cancers4.In the cellular regulatory pathways that control cell growth and proliferation, the products of oncogenes are inhibitory components and the products of tumour suppressor genes are stimulatory components5.When analysed, cancer cells are often found to have only one mutation in a regulatory pathway that controls cell proliferationA1 and 2B2 and 3C3 and 5D1, 2 and 4

2018 / H2 / IJC PRELIM / P1 Q184The diagram below illustrates the development of colorectal cancer. Which of these statements can be inferred from this multistep model of carcinogenesis?1Cells whose APC and β-ca