DP Biology (last assessment 2024)

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Question 20N.3.HL.TZ0.9

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Date November 2020 Marks available [Maximum mark: 6] Reference code 20N.3.HL.TZ0.9
Level HL Paper 3 Time zone TZ0
Command term Explain Question number 9 Adapted from N/A
9.
[Maximum mark: 6]
20N.3.HL.TZ0.9

Explain how psychoactive drugs affect the nervous system.

[6]

Markscheme

a. psychoactive drugs act upon the central nervous system/alter brain function;

b. psychoactive drugs are addictive;

Stimulants:
c. increase postsynaptic transmission;

d. mimic the stimulation provided by the sympathetic nervous system
OR
mimic action of natural stimulating neurotransmitters e.g. acetylcholine;

e. example: e.g. nicotine/cocaine/amphetamine;

Sedatives:
f. decrease postsynaptic transmission;

g. mimic inhibition (of the parasympathetic nervous system)
OR
mimic action of natural inhibiting neurotransmitters e.g. dopamine;

h. example: e.g. benzodiazepines/alcohol/tetrahydrocannabinol (THC);

Examiners report

Most candidates displayed a considerable knowledge about psychoactive drugs, but only the strongest candidates could provide focused answers and sufficient detailed mechanisms for both stimulants and sedatives on synapses.

Syllabus sections