Are biogenic amine neurotransmitters such as dopamine considered to be proteins?

• A. No, they are small molecules derived from amino acids, not proteins.
• B. No, they are lipids.
• C. Yes, all neurotransmitters are proteins.
• D. Yes, they are short-chain proteins.

Answer: (A)

Verified step by step guidance

1. Understand the term 'biogenic amine neurotransmitters': These are small molecules derived from amino acids that act as chemical messengers in the nervous system. Examples include dopamine, serotonin, and norepinephrine.
2. Clarify the distinction between proteins and small molecules: Proteins are large, complex molecules made up of chains of amino acids linked by peptide bonds, whereas small molecules like biogenic amines are derived from single amino acids and are much smaller in size.
3. Examine dopamine specifically: Dopamine is synthesized from the amino acid tyrosine through enzymatic reactions. It is not a protein but a small molecule derived from an amino acid.
4. Eliminate incorrect options: 'No, they are lipids' is incorrect because biogenic amines are not lipids. 'Yes, all neurotransmitters are proteins' is incorrect because not all neurotransmitters are proteins; some are small molecules like dopamine. 'Yes, they are short-chain proteins' is incorrect because dopamine is not a protein at all.
5. Conclude with the correct answer: Biogenic amine neurotransmitters like dopamine are small molecules derived from amino acids, not proteins.