IB DP Biology Option A: Neurobiology and behaviour (AHL) : A.5 Neuropharmacology SL Paper 3

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Question

Compare the effects of cocaine and THC.

[4]
a.

State one other example of an excitatory and an inhibitory psychoactive drug.

Excitatory drug:  ……………………………………………..

Inhibitory drug:  ……………………………………………..

[2]
b.
Answer/Explanation

Markscheme

Answers do not need to be in a table format.

 

a.

a. excitatory drug: nicotine / amphetamines/ other drug;
b. inhibitory drug: benzodiazepines / alcohol / other drug;

b.

Question

List two examples of excitatory psychoactive drugs.

[1]
a.

Outline the possible effects of excitatory drugs on mood and behaviour.

[2]
b.

Discuss the causes of addiction to cocaine.

[3]
c.
Answer/Explanation

Markscheme

nicotine;
cocaine;
amphetamines;
ecstasy;
Award [1] for any two. Consider the first two only, if there are more.

a.

a. increases arousal/alertness;
b. feelings of excitement/euphoria;
c. aggressive behaviour;
d. loss of judgement/self-control;
e. social withdrawal/depression/dysfunction;
f. loss of appetite;

b.

a. peer pressure / cultural traditions;
b. inherited / genetic predisposition;
c. social problems / trauma;
d. passed from mother to newborn/when breast feeding;
e. many stimulate synapses with dopamine as a transmitter / blocks re-uptake of dopamine;
f. pleasurable effects of dopamine/euphoria/regular use may lead to addiction;
g. increasingly large/more regular doses needed for effect;

c.

Question

State two effects that presynaptic neurons can have on postsynaptic transmission.

1.  …………………………………………………….
2.  …………………………………………………….

[1]
a (ii).

Suggest causes of addiction to drugs.

[3]
c.
Answer/Explanation

Markscheme

excite and inhibit (both needed)

a (ii).

a. dopamine stimulates brain’s reward system/pathways / addiction requires dopamine excess in brain;
b. inhibitory drugs/benzodiazepines/alcohol/drugs decrease neuron activity that inhibits dopamine release so brain becomes addicted;
c. excitatory drugs/cocaine/amphetamines/nicotine block removal of dopamine stimulating brain (reward system);
d. genetic component involved;
e. genetic tendency for addiction influenced by social factor/example of social factor (eg peer pressure, poverty, social deprivation, trauma, mental health problem/culture);

c.

Question

The diagram below shows a synapse where the neurotransmitter is dopamine and some of the processes that take place during nerve transmission.

Explain the effect of cocaine on neurotransmission at a synapse.

Answer/Explanation

Markscheme

a. dopamine initiates depolarization of post-synaptic membrane;
b. cocaine binds to (transporter) carrier proteins/proteins in pre-synaptic membrane;
c. cocaine blocks reabsorption (of dopamine);
d. cocaine causes dopamine build up in synaptic cleft/space;
e. so stimulus continues/cocaine is excitatory;

Question

List two examples of inhibitory psychoactive drugs.

1.

2.

Answer/Explanation

Markscheme

benzodiazepines;

alcohol;

tetrahydrocannabinol / THC / marijuana;

Do not accept brand names.

DateMay 2011Marks available3Reference code11M.3.SL.TZ1.15
LevelStandard levelPaperPaper 3Time zoneTime zone 1
Command termExplainQuestion number15Adapted fromN/A

Question

Explain the effects of psychoactive drugs on synaptic transmission.

Answer/Explanation

Markscheme

psychoactive drugs may increase or decrease transmission (to the post-synaptic membrane);
may increase the release/delay the breakdown/interfere with storage/uptake/reabsorption of neurotransmitters;
may mimic the action of neurotransmitters;
inhibitory drugs may reduce the effect of excitatory neurotransmitters / increase the effect/release of inhibitory neurotransmitters;
inhibitory drugs can hyperpolarize the post-synaptic neuron;

Question

State one example of an excitatory and one example of an inhibitory psychoactive drug.

Excitatory: …………………………………………………..

Inhibitory: …………………………………………………..

[2]
a.

Discuss causes of addiction.

[3]
c.
Answer/Explanation

Markscheme

excitatory: cocaine / nicotine / amphetamines;
inhibitory: benzodiazepines / alcohol / THC;
Accept other suitable examples.

 

a.

addictive drugs trigger secretion of dopamine which causes feelings of pleasure/ well-being/reward / users become dependent on feelings;
genetic predisposition is most common with addiction to alcohol;
social factors affect the incidence of addiction;
it is not certain that a person who is genetically predisposed will develop addiction when exposed to the drug / OWTTE;
although many drugs are (potentially) addictive, not every user becomes an addict;

named social factors which must be explained:
e.g. cultural traditions / peer pressure;
social deprivation / traumatic life experiences / mental problems;

c.

Question

Explain the effects of cocaine in terms of action at synapses in the brain.

Answer/Explanation

Markscheme

cocaine affects synapses using dopamine as neurotransmitter;
cocaine attaches to dopamine receptors on presynaptic membrane;
blocks dopamine transporters/prevents re-uptake / causes dopamine to persist in the synaptic cleft;
amplifies synaptic transmission / is an excitatory psychoactive drug / causes constant stimulation of postsynaptic neuron;
dopamine builds up in the synapse contributing to euphoria/pleasurable effects;

Question

Distinguish between innate and learned behaviour.

[1]
a.

Outline the role of inheritance and learning in the development of birdsong in young birds.

[2]
b.

Explain the effects of cocaine on mood and behaviour.

[2]
c.
Answer/Explanation

Markscheme

innate behaviour develops independently of the environmental context/genetically
inherited and learned behaviour develops as a result of experience / OWTTE

a.

young birds learn birdsong from parents/other adults;
young birds removed from parents capable of own song;
basic song template may be inherited;
learned birdsong is louder/richer;

b.

(cocaine causes) dopamine build up in synapses / continuous neurotransmitter presence;
increased energy/alertness/feeling of euphoria/pleasure;
user becomes isolated/suspicious/less productive / alienates family and friends;
cocaine addiction/use may lead to crime/robbery to buy cocaine;

c.

Question

Explain the effects of tetrahydrocannabinol (THC) in terms of its action at synapses in the brain.

Answer/Explanation

Markscheme

THC binds to cannabinoid receptor;
blocks release of (excitatory) neurotransmitter;
therefore it is inhibitory;
euphoria/anxiety/short-term memory loss/impaired coordination/pain relief;
extended use leading to social dysfunction/addiction;

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