The signal finally triggers a specific cellular activity, such as gene expression or enzyme activation. Types of Signaling: Autocrine: A cell targets itself.
Nearby cells are targeted (e.g., neurotransmitters). signaling
The receptor triggers a relay of intracellular molecules, often called a signaling cascade (e.g., using G-proteins or kinases). The signal finally triggers a specific cellular activity,
Long-distance signaling via the bloodstream (e.g., hormones). often called a signaling cascade (e.g.