Question

Most signal molecules ('primary messenger'):

A. Diffuse through the membrane and bind to a receptor in the cytoplasm
B. Bind to the membrane receptors and transmit information across a membrane without traveling the membrane
C. Enter the cell via receptor-mediated endocytosis
D. A and C
E. A, B, and C

Answer 1

Answer and Explanation: The correct answer is B. The majority of the primary messengers are ligands that bind to cell-surface (membrane) receptors. Such ligands are unable to penetrate through the cell membrane due to their polar or hydrophilic structure