Lesson 3.8.2.3.1

3.8.2.3.1 Gene expression and cancer Quiz: AQA Biology, Unit 8

20 questions

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Lesson 3.8.2.3.1, Gene expression and cancer: 20 multiple choice questions for the AQA Biology (7402), Unit 8: The control of gene expression, written with Revision Ninja.

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The 20 questions

  1. A benign tumour is best described as one that:

    • Is always caused by a virus
    • Remains localised and does not invade surrounding tissue
    • Invades surrounding tissue and spreads to other organs
    • Disappears spontaneously after a few weeks
  2. A malignant tumour is characterised by:

    • Being made of cells that have all become tumour suppressors
    • Stopping all cell division permanently
    • Invading surrounding tissue and possibly spreading to other parts of the body
    • Remaining in one place with no change in cell division
  3. What is the normal role of tumour suppressor genes?

    • They normally slow or stop cell division, so loss of their function can promote cancer
    • They normally increase cell division rapidly in all tissues, so that the body can repair damage quickly and cancer is prevented
    • They normally break down the cell membrane to release nutrients, so their loss allows cells to take in more glucose and grow faster
    • They normally make new blood vessels only in tissues that are growing, so their loss stops the tumour from getting a blood supply
  4. What is the normal role of oncogenes when they are not mutated or overactive?

    • They break down tumour suppressor genes
    • They promote cell division as part of normal growth control
    • They carry the genetic code for ribosomes
    • They always stop cell division
  5. Abnormal methylation of a tumour suppressor gene tends to:

    • Duplicate the gene in every cell
    • Increase the amount of suppressor protein made
    • Change the codon sequence of the gene
    • Switch the gene off so less suppressor protein is made
  6. Increased oestrogen concentrations are linked to the development of:

    • All forms of skin cancer
    • Only blood cancers
    • Some breast cancers
    • Only lung cancers caused by smoking
  7. An oncogene is most likely formed when:

    • A cell becomes a totipotent stem cell
    • A normal growth-promoting gene is mutated or overexpressed
    • A tumour suppressor gene is lost from every cell
    • A cell loses its nucleus during division
  8. One tumour suppressor allele is inactivated and the second copy is lost in a cell. What is the most likely effect?

    • The cell stops making any proteins, so it can no longer carry out its normal functions and dies within a few hours of the mutation
    • The cell becomes a pluripotent stem cell that can form any tissue, so the cell is able to repair the damaged body tissue quickly
    • The cell's DNA is copied more slowly during each division, which gives the body extra time to repair errors before they accumulate
    • Loss of normal control of cell division, increasing the risk of cancer
  9. A study shows that higher oestrogen levels are correlated with more breast cancers. Which interpretation is best?

    • The correlation shows that breast cancer has no link to hormones, because hormone levels are found to be unrelated to any cancer risk
    • The correlation suggests a link but does not on its own prove that oestrogen causes the cancers
    • The correlation shows that oestrogen is a type of tumour suppressor, since higher oestrogen always reduces the number of cells that divide
    • The correlation proves that oestrogen directly causes all breast cancers
  10. A drug blocks the activity of an overactive oncogene protein. What is the most likely effect on tumour cells?

    • Increased cell division because more oncogene is made
    • Reduced cell division in the tumour cells
    • Faster metastasis to other organs
    • Increased methylation of all tumour suppressor genes
  11. Which feature best distinguishes malignant tumours from benign tumours?

    • Benign tumours always spread through the blood to distant organs, where they then form new tumours in the liver and lungs
    • Malignant tumours invade surrounding tissue and may spread to other parts of the body
    • Malignant tumours are always smaller than benign tumours, because their cells divide more slowly
    • Malignant tumours never contain mutated cells, since the growth is driven by normal cells that are reacting to the surrounding environment
  12. Which evidence best supports a causal link between an environmental factor and a cancer?

    • A consistent correlation across large studies together with a plausible biological mechanism
    • A belief among patients that the factor is harmful, which is widely held and so provides good evidence that the factor is the cause
    • A correlation that was observed only once in a small sample of patients, which is enough to show that the factor causes the cancer
    • A single case in which one person developed the cancer after exposure to the factor
  13. A demethylating drug is used on a tumour. Why might this help?

    • It destroys all oncogene mRNA in the tumour cells, which removes every growth signal in the tumour and makes it stop dividing at once
    • It increases the methylation of all tumour suppressor genes in the tumour, so that the suppressor proteins are made in larger amounts
    • It makes the tumour cells totipotent so they stop dividing and then differentiate into normal cells of the surrounding tissue
    • It may restore expression of tumour suppressor genes that were silenced by methylation
  14. Which of these is a tumour suppressor gene?

    • Ras, an oncogene
    • A gene encoding a growth factor receptor
    • p53
    • Myc, an oncogene
  15. How many cell divisions starting from one cell give about one million cells?

    • 6
    • 100
    • 20
    • 10
  16. Why must researchers be cautious about correlations between environmental factors and cancers?

    • Environmental factors never affect cancer risk
    • Cancers occur only in people who have no environmental exposure
    • Many factors vary together, so controlled evidence is needed to establish cause
    • Correlations always show direct causation
  17. How does activation of an oncogene differ from loss of a tumour suppressor?

    • Both give a loss of function that stops cell division, so the tumour cells stop growing and the tumour is kept small and benign
    • Oncogene activation stops division while tumour suppressor loss increases division, so the two changes act in opposite directions
    • Both give a gain of function that stops cell division, so the tumour cells gain extra control over their own growth and shrink
    • Oncogene activation gives a gain of function, while tumour suppressor loss gives a loss of function, both promoting division
  18. A tumour shows methylation of a tumour suppressor gene. What is the likely consequence?

    • The gene is silenced, so less suppressor protein is made and the tumour may grow unchecked
    • The tumour becomes benign because its genes are unmethylated, so the cells lose their ability to divide and stop invading tissue
    • The gene is overexpressed, so the tumour makes large amounts of suppressor protein and stops growing within a few cell cycles
    • The gene's DNA sequence is replaced with that of an oncogene, which permanently changes the base order in every cell of the tumour
  19. How could an understanding of oncogenes and tumour suppressor genes help treat cancer?

    • It allows the tumour cells to be converted into harmless stem cells in a single step, with no risk of any further growth at all
    • It proves that all cancers are inherited through the germ line without any environmental cause, so treatment is never needed for the cancer
    • Drugs can target overactive oncogene products or restore tumour suppressor activity to reduce abnormal growth
    • It allows doctors to remove all genes from the tumour cells surgically, so that no cell in the patient's body can divide again in future
  20. Why are both copies of a tumour suppressor gene usually inactivated before cancer develops?

    • A single copy always produces too much suppressor protein, which then blocks all cell division and so stops the tumour from ever forming
    • Tumour suppressor genes exist only in a single copy in each cell, so one inactivated allele is enough to remove all control of division
    • Tumour suppressor genes are only active after both copies are removed, so their activity increases once the cell has lost both alleles
    • Cells normally carry two working copies, so both must be lost before control of division is removed

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