What are two types of receptors that help transmit signals across the cell membrane?

Ionotropic and metabotropic. Ionotropic is when the substance binds to the receptor, it causes the protein to change shape, opening thr channel for specific ions. Metabotropic is the second messenger model, where the substance binds, then activates certain enzymes and causes something to happen. E.g. Insulin might bind to receptors on the liver, activating an enzyme, causing glucose to be converted to glycogen (glycogenesis).