Final answer:
A gene is a sequence of DNA nucleotides that codes for polypeptide chains or RNA molecules, and is transcribed into mRNA which is then translated into protein at the ribosome.
Step-by-step explanation:
The correct answer to the question is c) Gene. A gene is a sequence of DNA nucleotides that is transcribed into RNA. Based on the genetic information within a gene, either at least one polypeptide may be produced, which will contribute to a protein's structure and function, or an RNA molecule may be produced that has other roles within the cell. During transcription, a gene's DNA sequence is copied into mRNA, which then travels to the ribosome, where it is translated into a chain of amino acids forming a polypeptide. Each three-nucleotide sequence on the mRNA, known as a codon, corresponds to a specific amino acid.
The genetic code consists of the DNA alphabet (A, T, C, G), the RNA alphabet (A, U, C, G), and the polypeptide alphabet (20 amino acids). The process by which a gene is turned 'on' to be transcribed into mRNA, which is then translated to produce a polypeptide chain at the ribosome, represents the central dogma of molecular biology illustrating the flow of genetic information: from DNA, to RNA, to protein.