Question

How do we know that mRNA exists and serves as an intermediate between information encoded in DNA and its concomitant gene product?

Accepted Answer

Understand the central dogma of molecular biology, which states that genetic information flows from DNA to RNA to protein, implying the existence of an intermediate molecule (mRNA) that carries information from DNA to the protein synthesis machinery. Examine experimental evidence such as pulse-chase experiments where cells are exposed to radioactive nucleotides for a short time (pulse) and then non-radioactive nucleotides (chase), allowing tracking of newly synthesized RNA and proteins to show that RNA appears before protein synthesis. Consider the discovery of different types of RNA, including messenger RNA (mRNA), which was identified as a transient RNA species that carries the genetic code from DNA in the nucleus to ribosomes in the cytoplasm where proteins are made. Review experiments where inhibition of RNA synthesis (using drugs like actinomycin D) leads to a halt in protein synthesis, indicating that RNA is necessary as an intermediate for protein production. Analyze the molecular characteristics of mRNA, such as its sequence complementarity to DNA and its ability to be translated by ribosomes, confirming its role as the intermediate between DNA and protein.

How do we know that mRNA exists and serves as an intermediate between information encoded in DNA and its concomitant gene product?

주요 개념

Central Dogma of Molecular Biology

Experimental Evidence for mRNA

Transcription and Translation Processes