Download B3a Worksheet 3: DNA

Worksheet B1e 3
Drugs
1. Name two types of class B drugs.
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2. Why do you think new drugs have to be tested before they are licensed for use as
medicines?
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3. What are hallucinogens?
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4. Explain how (a) depressants and (b) stimulants work.
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5. Cannabis is a ‘class B’ drug. Here are some facts about cannabis:
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may cause mental illness.
does not seem to cause major social problems.
has a higher tar content than tobacco.
is a very effective painkiller.
affects the heart in a similar way to the effects of exercise.
may be a ‘gateway’ drug to more harmful substances.
is less addictive than tobacco or alcohol.
can interfere with the body’s control of blood pressure.
Give three reasons why some people think that cannabis should be reclassified as a
‘class A’ drug.
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Worksheet B1e 3 continued
6. Give three reasons why some people think cannabis should not be classified as an
illegal drug.
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7. An investigation was carried out into the link between smoking cannabis and heroin
addiction.
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Six young rats were given a small dose of the active ingredient in cannabis every
three days.
The dose given was equivalent to a teenage human smoking one cannabis ‘joint’.
Another six rats of the same age did not receive the cannabis ingredient.
After eight weeks, both groups of rats were fitted with catheters (tubes) so that
they could administer heroin to themselves by pushing a lever.
All the rats began to administer heroin frequently and then stabilised their dose.
The ones that had been given cannabis stabilised at a much higher dose than those
in the control group.
Evaluate this investigation: consider the reliability, validity and usefulness of the study.
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