Two human neurones grown in a laboratory communicate across a synapse. The receiving neurone has just produced an electrical impulse, and neurotransmitter molecules are still present in the synaptic gap.
What happens when the signal has been transmitted across the synapse?
the neurotransmitter remains in the gap and repeatedly stimulates the receiving neurone
the neurotransmitter is broken down or reabsorbed, preventing continuous stimulation
the neurotransmitter permanently attaches to the receiving neurone and blocks later signals
the neurotransmitter becomes an electrical impulse while it remains inside the gap
111 exam-style questions on Edexcel GCSE Biology 2.3 The nervous system and brain, covering 2.3.1 Structures and functions of the brain, 2.3.2 Imaging brain function with scanning, 2.3.3 Limitations in treating nervous system damage, 2.3.4 Neurones and impulse transmission, and 2.3.5 Structure and function of a reflex arc. Each one has a worked solution and a mark scheme showing where the marks go.