Which of the following components of a prokaryotic operon contains the coding information for amino acids?

• A. Promoter
• B. Operator
• C. Regulator gene
• D. Structural genes

Answer: (D)

Verified step by step guidance

1. Understand the structure of a prokaryotic operon: An operon is a cluster of genes under the control of a single promoter. It typically includes a promoter, an operator, and one or more structural genes.
2. Define the role of each component: The promoter is the DNA sequence where RNA polymerase binds to initiate transcription. The operator is a regulatory sequence where repressor proteins can bind to control gene expression. The regulator gene codes for the repressor protein but is not part of the operon itself.
3. Focus on the structural genes: Structural genes are the parts of the operon that contain the coding sequences for proteins. These sequences are transcribed into mRNA and then translated into amino acids, forming functional proteins.
4. Clarify why structural genes are the correct answer: Among the listed options, only structural genes directly contain the coding information for amino acids, as they are transcribed into mRNA that specifies the amino acid sequence of proteins.
5. Conclude the reasoning: The promoter, operator, and regulator gene are involved in the regulation of gene expression, but they do not directly encode amino acids. Therefore, the structural genes are the correct answer.