Chemicals

Light

Vibrations

Gravity

Sound

Ligands usually make covalent bonds with their receptors.

It is possible for a receptor to bind more than one ligand.

The receptor for a ligand may either be on the cell's surface or inside the cytoplasm.

Binding of a ligand always turns on the protein to which it is bound.

Ligands are usually proteins.

Substrates, inhibitors, activators, and neurotransmitters

Substrates, inhibitors, activators, and tracers

Substrates, inhibitors, neurotransmitters, and tracers

Substrates, activators, neurotransmitters, and tracers

Inhibitors, activators, neurotransmitters, and tracers

Integral membrane proteins

Calcium ions

Steroids

Neurotransmitters

Inhibitors