G. An explanation of the Genetic Code: DNA is a two-stranded molecule. Each strand is a polynucleotide composed of A (adenosine), T (thymidine), C (cytidine), and G (guanosine) residues polymerized by dehydration synthesis in linear chains with specific sequences.
Note: There are more than two types of epinephrine receptors on smooth muscle cells, so epinephrine may affect smooth muscle in other tissues in other ways. (There are subtypes of alpha and subtypes of beta.) * Details of how PLC generates IP3 are on handout 12A. We will go over this later.
Production of epinephrine. 1  Epinephrine is produced specifically in the adrenal medulla, where the amino acid tyrosine is transformed through a series of reactions to norepinephrine. An enzyme known as phenylethanolamine N-methyltransferase, which is found in the chromaffin cells of the adrenal medulla, catalyzes the methylation of norepinephrine to epinephrine.