Final answer:
The statement that S-adenosylmethionine (AdoMet, or SAM) is a methyl group donor in numerous metabolic reactions is True. As a key methylating agent in biological systems, SAM is essential in synthesizing amino acids, including the conversion of noradrenaline to adrenaline, and in nucleotide metabolism.
Step-by-step explanation:
S-adenosylmethionine (abbreviated AdoMet or SAM) is indeed a methyl group donor in numerous metabolic reactions, making the statement True. SAM is synthesized from ATP and methionine by the action of the enzyme methionine adenosyltransferase. This molecule plays a critical role in the synthesis of amino acids and nucleotide metabolism, serving as a methylating agent to facilitate various biochemical reactions. For instance, SAM is used to convert noradrenaline to adrenaline by transferring a methyl group in a process known as transmethylation. Similarly, in the synthesis of cysteine, an essential amino acid, methionine is first converted to SAM, which then participates in a series of reactions culminating in the production of cysteine. The biological importance of SAM as a methyl donor accentuates its central role in the complex network of metabolic pathways.