If you coil the wire around and around, it will make the magnetic force stronger, but it will still be pretty weak. ... The strength of an electromagnet can be increased by increasing the number of loops of wire around the iron core and by increasing the current or voltage.
Answer:
A presynaptic neuron knows when and how much of a certain neurotransmitter it has to release into the synapse by the frequency of the action potential.
Explanation:
Two nuerons connect to each other through synapse. When an action potential, or nerve impulse, arrives at the axon terminal, it activates voltage-gated calcium channels in the cell membrane, then the calcium which is present in hi highconcentration outside the neuron than inside, rushes into the cell. The Calcium then allows synaptic vesicles to fuse with the axon terminal membrane, releasing neurotransmitter into the synaptic cleft.
The nuerotransmitter than binds to the receptors at the post-synaptic cleft and causes the opening or closing of the channels, hence, depolarizing or hyperpolarizing the cells.This can produce a change in the membrane potential—voltage across the membrane of the receiving cell.
A phospholipid bilayer or lipid bilayer is a double layer of lipids in a cell membrane which has a hydrophobic and a hydrophilic part.
Hydrophobic - expelled by water
Hydrophilic - attracted to water
The layers form the cell membrane which means that it's functions are the same as the functions of a cell membrane, and are critic to the cells functioning.
Hope it helped,
BioTeacher101