Final answer:
The statement that slow postsynaptic potentials are caused by the opening or closing of ion channels whereas fast postsynaptic potentials only involve the opening of ion channels is false. Both types of postsynaptic potentials involve changes in ion channel states. Therefore, correct option is b.
Step-by-step explanation:
True or False: Slow postsynaptic potentials can be caused by the opening or closing of ion channels, whereas fast postsynaptic potentials only involve the opening of ion channels. The statement is false.
While fast postsynaptic potentials, such as excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs), are typically associated with the rapid opening of ion channels, slow postsynaptic potentials can indeed be the result of both the opening and closing of ion channels.
For instance, the binding of GABA (gamma-aminobutyric acid) to its receptors on the postsynaptic neuron can lead to the opening of Cl- ion channels, resulting in an IPSP that hyperpolarizes the neuron and makes it less likely to fire an action potential.
Conversely, acetylcholine binding to receptors at a neuromuscular junction causes Na+ ion channels to open, depolarizing the neuron and creating an EPSP.
In summary, both types of postsynaptic potentials involve changes in ion channel states, not just the opening of them as implied in the statement.