Questions: Graded potentials result from the opening of leakage channels ligand-gated channels voltage-gated channels ATP pumps

The answer is the second one: ligand-gated channels.

Explanation for each option:

1. Leakage channels: These channels are always open and allow ions to move across the membrane according to their concentration gradient. They do not typically result in graded potentials, as they are not responsive to specific stimuli.

2. Ligand-gated channels: These channels open in response to the binding of a chemical messenger (ligand), such as a neurotransmitter. The opening of ligand-gated channels can cause changes in the membrane potential, leading to graded potentials. Therefore, this is the correct answer.

3. Voltage-gated channels: These channels open in response to changes in membrane potential and are primarily involved in the generation and propagation of action potentials, not graded potentials.

4. ATP pumps: These are active transport mechanisms that use ATP to move ions against their concentration gradient. They do not directly result in graded potentials.

In summary, graded potentials result from the opening of ligand-gated channels.