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Explain the generation of the resting potential in neurones.

The resting potential in neurones is generated by the unequal distribution of ions across the neuronal membrane.

The resting potential is a fundamental aspect of neuron function. It refers to the electrical potential difference across the neuron's membrane when it is not transmitting any signals. This is typically around -70 millivolts (mV). The generation of this resting potential is primarily due to the unequal distribution of ions, particularly sodium (Na+) and potassium (K+), across the neuronal membrane.

The neuronal membrane is semi-permeable, meaning it allows certain ions to pass through while blocking others. It is more permeable to K+ ions than to Na+ ions due to the presence of 'leak channels'. These are protein channels that allow K+ ions to pass through the membrane more easily than Na+ ions. As a result, there is a higher concentration of K+ ions inside the neuron and a higher concentration of Na+ ions outside the neuron.

The sodium-potassium pump, a type of active transport, also plays a crucial role in maintaining this ion gradient. For every cycle, this pump uses one ATP molecule to transport three Na+ ions out of the neuron and two K+ ions into the neuron. This further contributes to the higher concentration of Na+ ions outside the neuron and K+ ions inside the neuron.

The unequal distribution of these ions creates an electrical gradient across the membrane. Because ions are charged particles, their movement across the membrane can generate an electrical potential. The inside of the neuron is negatively charged compared to the outside, creating the resting potential.

In summary, the resting potential in neurones is generated by the unequal distribution of ions across the neuronal membrane, primarily due to the selective permeability of the membrane and the action of the sodium-potassium pump. This resting potential is essential for the neuron's ability to transmit signals, as changes in this potential allow for the generation of action potentials, the neuron's method of signal transmission.

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