OCR GCSE Biology Practice Exam 2025 – Comprehensive All-in-One Guide to Exam Success

The production of a protein occurs after the ribosomes have read the complete gene. Ribosomes are the cellular machinery responsible for translating messenger RNA (mRNA) into a polypeptide chain, which eventually folds into a functional protein. This process involves reading the genetic code carried by mRNA, translating the sequence of nucleotide bases into a specific sequence of amino acids, which then links together to form a protein.

Understanding this process is crucial because it illustrates the central dogma of molecular biology: DNA is transcribed into RNA, and RNA is translated into protein. Therefore, once the ribosomes complete reading the gene, they synthesize a protein, fulfilling a critical role in cell function and maintaining life processes.

The other options would not be produced directly as a result of the ribosomes reading the gene. RNA is involved in the process but is not the final product of translation. Free amino acids are the building blocks used during protein synthesis but are not the end product. DNA is the genetic material itself and is not produced during the translation of mRNA by ribosomes.