A scientist grows two neurones in a laboratory. The neurones form a synapse with a gap that is 0.00000004 m wide.
Give the width of the gap in standard form.
Name the chemical released from the first neurone into the gap.
Describe what happens to this chemical after it is released and before a new electrical impulse starts in the second neurone.
The scientist also grows two pathways of neurones. The total axon length is the same in both pathways, and the axons are myelinated in the same way. Pathway P contains two synapses and pathway Q contains five synapses.
Explain which pathway will transmit an impulse sooner.
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.