Final answer:
DNA (Deoxyribonucleic Acid) carries the genetic instructions for how to build a specific polypeptide. It is transcribed into messenger RNA (mRNA), which then translates these instructions during protein synthesis. This embodies the central dogma of molecular biology: DNA → RNA → Protein.
Step-by-step explanation:
Which Molecule Carries Genetic Instructions for Polypeptide Synthesis?
The molecule that carries the genetic instructions for how to build a specific polypeptide is DNA (Deoxyribonucleic Acid). DNA holds the genetic code that is transcribed to messenger RNA (mRNA), which is then used to synthesize polypeptides during protein synthesis. This process is a fundamental concept known as the central dogma of molecular biology, which can be summarized as DNA → RNA → Protein. Each gene in the DNA molecule corresponds to a specific polypeptide chain, with the genetic code represented in a sequence of nucleotide bases. The information encoded in the DNA sequence is transcribed into mRNA, which then travels from the nucleus to the ribosomes, where the instructions are translated into the amino acid sequence of a polypeptide.
Despite the critical role of mRNA in protein synthesis, it is important to note that it is DNA that contains the inherited genetic material and the instructions for making all the proteins in an organism. It is the segment of DNA that carries the codes for making specific polypeptides, while mRNA is merely the messenger that conveys this genetic information from the DNA to the ribosome during protein synthesis.