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Exam questions · Biology · Defence Against Disease

Discovery and Development of Drugs

  • 7 exam questions
  • 17 marks
  • 8 quick checks
  1. 1 State [1 mark]

    Name the plant from which the heart drug digitalis originates.

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    Model answer

    Foxglove.

    Mark scheme

    • Foxglove — 1 mark
  2. 2 State [2 marks]

    State what is meant by the toxicity and the efficacy of a drug.

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    Model answer

    Toxicity is how harmful the drug is. Efficacy is how well the drug works.

    Mark scheme

    • Toxicity: harmful effects — 1 mark
    • Efficacy: how well it works — 1 mark
  3. 3 Describe [2 marks]

    Describe what happens in preclinical testing of a new drug.

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    Model answer

    The drug is tested in a laboratory on cells and tissues, and then on live animals, to see if it is safe and effective.

    Mark scheme

    • Tested on cells and tissues — 1 mark
    • Tested on live animals — 1 mark
  4. 4 Explain [2 marks]

    Explain why very low doses of a drug are given at the start of a clinical trial.

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    Model answer

    The drug may be harmful to people. A low dose reduces the risk of serious side effects while its safety is checked.

    Mark scheme

    • The drug may be harmful — 1 mark
    • A low dose reduces the risk — 1 mark
  5. 5 Explain [3 marks]

    Explain why some patients in a clinical trial are given a placebo.

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    Model answer

    A placebo contains no drug. Patients may feel better just because they believe they are being treated. Comparing the group that has the drug with the group that has the placebo shows whether the drug itself has an effect.

    Mark scheme

    • A placebo has no drug — 1 mark
    • Patients may feel better just by believing — 1 mark
    • Comparison shows the effect of the drug — 1 mark
  6. 6 Explain [3 marks]

    Explain why clinical trials are double-blind.

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    Model answer

    Neither the patients nor the doctors know who is receiving the drug and who is receiving the placebo. This stops the patients' or doctors' expectations changing how the patients report their symptoms or how the doctors judge the results, so the results are not biased.

    Mark scheme

    • Neither patients nor doctors know — 1 mark
    • Expectations could affect the results — 1 mark
    • Results are less biased — 1 mark
  7. 7 Explain [4 marks]

    Explain why the results of a clinical trial are not accepted until they have been through peer review.

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    Model answer

    Other scientists in the same field check the methods and the conclusions of the trial for mistakes or bias. This stops false or careless claims being accepted. The work can also be repeated by other scientists to see if they get the same results, which makes the findings more reliable.

    Mark scheme

    • Checked by other scientists — 1 mark
    • Looks for mistakes or bias — 1 mark
    • Stops false claims — 1 mark
    • Results can be repeated — 1 mark

Quick check

  1. 1

    Which painkiller originates from willow?

    1. AAspirin
    2. BDigitalis
    3. CPenicillin
    4. DParacetamol
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    A: Aspirin

    Aspirin originates from the bark of the willow tree.

  2. 2

    Who discovered penicillin?

    1. ALouis Pasteur
    2. BCharles Darwin
    3. CAlexander Fleming
    4. DEdward Jenner
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    C: Alexander Fleming

    Alexander Fleming discovered penicillin from the Penicillium mould.

  3. 3

    What is a placebo?

    1. AA very strong drug
    2. BA treatment containing no drug
    3. CA type of antibiotic
    4. DA vaccine
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    B: A treatment containing no drug

    A placebo is a dummy treatment that contains no active drug.

  4. 4

    Where are drugs first tested?

    1. AIn patients
    2. BIn healthy volunteers
    3. CIn hospitals
    4. DIn the laboratory on cells, tissues and animals
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    D: In the laboratory on cells, tissues and animals

    Preclinical testing uses cells, tissues and live animals in the laboratory.

  5. 5

    What does efficacy mean?

    1. AHow well a drug works
    2. BHow harmful a drug is
    3. CHow much of a drug to give
    4. DHow much a drug costs
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    A: How well a drug works

    Efficacy is how well a drug works.

  6. 6

    In a double-blind trial, who does not know who has the drug?

    1. AOnly the patients
    2. BOnly the doctors
    3. CBoth the patients and the doctors
    4. DNobody does at any time
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    C: Both the patients and the doctors

    Neither the patients nor the doctors know, which prevents bias.

  7. 7

    What is the purpose of peer review?

    1. ATo advertise the drug
    2. BTo check the work before it is published
    3. CTo give the drug to patients
    4. DTo choose the dose
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    B: To check the work before it is published

    Other scientists check the work for mistakes before it is published.

  8. 8

    Why are the first trials in healthy volunteers done at a very low dose?

    1. ATo make the drug cheaper
    2. BTo test efficacy only
    3. CTo find the best dose
    4. DTo check it is safe
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    D: To check it is safe

    The drug might be harmful, so the lowest safe dose is used first to check safety.