Which sequence best describes the central flow of genetic information in cells?

• A. DNA → RNA → Protein
• B. Protein → RNA → DNA
• C. RNA → DNA → Protein
• D. DNA → Protein → RNA

Answer: (A)

Genetic information flows from DNA to RNA to Protein. DNA contains genes and is transcribed into messenger RNA, which then travels to ribosomes where it is translated into a polypeptide chain with the help of tRNA. That chain folds into a functional protein. This sequence fits how cells read and use genetic information: a DNA template is copied into RNA, and the RNA's instruction is used to build proteins. The other sequences would imply directions that aren’t how gene expression works in cells, though there are exceptions like reverse transcription in some viruses. But for standard cellular processes, the path is DNA → RNA → Protein.