AICE Psychology Paper 2 Practice Exam

Neurotransmitters are essential chemical messengers in the nervous system that play a crucial role in transmitting signals across synapses, which are the junctions between neurons. When an electrical impulse, or action potential, travels down a neuron and reaches the synapse, neurotransmitters are released from the presynaptic neuron into the synaptic cleft. These chemicals then bind to specific receptors on the postsynaptic neuron, allowing the signal to continue its journey through the nervous system. This process is vital for communication between neurons and underlies many aspects of mental and physical function, including mood regulation, movement, and cognitive functions.

The other options do not accurately define neurotransmitters. Hormones and neurotransmitters both influence mood, but hormones are produced by the endocrine system and have a different mode of action. Proteins that build neuron structures refer to the physical components of neurons, such as dendrites and axons, rather than the signaling chemicals. Cells that generate electrical impulses refer to neurons themselves, rather than the neurotransmitters that facilitate communication between these cells. This distinction reinforces the specific role of neurotransmitters in neuronal signaling.