What is the central dogma of molecular biology?

• A. DNA is transcribed into RNA, which is translated into protein
• B. Protein is transcribed into RNA, then DNA
• C. RNA is replicated into DNA and then transcribed into protein
• D. RNA is translated into DNA, then protein

Answer: (A)

Information flows from DNA to RNA to protein. In transcription, a gene in DNA is used as a template to synthesize messenger RNA. The mRNA then travels to a ribosome, where translation reads its codons and assembles the corresponding amino acids to form a protein. This sequence—DNA to RNA to protein—explains how genetic information is expressed, which is why this option is the best description of the central dogma. The other statements mix up the order or skip the RNA step; for example, translating RNA into DNA or using proteins to produce DNA runs counter to the standard flow. There are special cases like reverse transcription in some viruses, but they are exceptions rather than the rule and don’t redefine the general flow. Replication of DNA is about copying genetic material for cell division and isn’t part of the gene-expression pathway.