Nitric oxide is considered a paracrine signal molecule because it
A) is slow to diffuse.
B) is produced in very small quantities.
C) is unstable, with a short half-life.
D) binds to cell surface receptors that are very plentiful.

Question

Quizplus · Accepted Answer

Nitric oxide is considered a paracrine signal molecule because it is unstable, with a short half-life. This means that it can only act locally on nearby cells before it breaks down or reacts with other molecules, making it a paracrine signal rather than an endocrine or autocrine signal that can travel longer distances.

Nitric Oxide Is Considered a Paracrine Signal Molecule Because It