OCR GCSE Biology Practice Exam 2025 – Comprehensive All-in-One Guide to Exam Success

Releasing transmitter chemicals at a synapse is crucial for the transmission of signals between neurons. These chemicals, known as neurotransmitters, are released from the presynaptic neuron and cross the synaptic cleft to bind to specific receptors on the postsynaptic neuron. This binding is what triggers the generation of new electrical impulses in the adjacent neuron.

When neurotransmitters bind to their corresponding receptors, they can cause ion channels to open or close, leading to changes in the membrane potential of the postsynaptic neuron. If the change is sufficient, it can initiate an action potential, thus continuing the signaling process down the neural pathway. This transmission is essential for the communication within the nervous system, allowing for complex functions such as reflexes, thoughts, and movements.

The process does not create a gap in signaling nor does it slow down transmission; instead, it facilitates the rapid exchange of information between neurons. While enhancing the connection between neurons can be a longer-term effect of repeated signaling, the immediate action of transmitter chemicals is primarily to trigger new electrical impulses.