Study the diagram of a synapse above. Label the following structures: A (Synaptic vesicle), B (Synaptic cleft), C (Receptor protein).

Describe how an impulse is transmitted across a synapse. [6 marks]

Explain why there is a delay when signals cross a synapse. [2 marks]

State what happens to neurotransmitter molecules after they have transmitted the signal. [2 marks]

Suggest why some drugs affect synaptic transmission. [3 marks]

Explain how synapses ensure one-way transmission of nerve impulses. [4 marks]

A student investigates reaction time using a ruler drop test. The ruler is dropped and caught. Suggest why there is always a minimum reaction time, even for the fastest person. [3 marks]

Describe how you would use the ruler drop test to investigate the effect of caffeine on reaction time. Include variables and safety. [5 marks]

A neurotoxin prevents vesicles from releasing neurotransmitters. Predict the effect on nerve transmission. [2 marks]

Explain why synapses allow more complex responses than a simple reflex arc. [3 marks]