Messenger RNA

Definition

Messenger RNA (mRNA) is a single-stranded molecule that carries genetic information from DNA to the ribosome, where proteins are synthesized. It serves as an intermediary between the genetic code stored in DNA and the amino acids that make up proteins, playing a crucial role in the process of gene expression.

5 Must Know Facts For Your Next Test

1. mRNA is synthesized during transcription, where RNA polymerase reads the DNA template and produces a complementary RNA strand.
2. The mRNA molecule is processed before it can be translated, which includes capping, polyadenylation, and splicing to remove introns.
3. Each mRNA molecule has a sequence of codons that correspond to specific amino acids, determining the protein that will be produced.
4. In eukaryotic cells, mRNA must exit the nucleus to reach the ribosomes in the cytoplasm for translation.
5. The lifespan of mRNA varies; some mRNA molecules are rapidly degraded while others are stable and can be translated multiple times.

Review Questions

• How does messenger RNA contribute to gene expression and what steps are involved from transcription to translation?
  • Messenger RNA plays a critical role in gene expression by acting as the carrier of genetic information from DNA to ribosomes. The process begins with transcription, where mRNA is synthesized from a DNA template. After mRNA is produced, it undergoes processing to become mature mRNA, which includes capping, polyadenylation, and splicing. Once processed, mRNA is transported out of the nucleus to ribosomes, where translation occurs, converting the mRNA sequence into a specific protein.
• What are the key differences between prokaryotic and eukaryotic messenger RNA processing?
  • In prokaryotes, messenger RNA is typically transcribed and immediately used for translation without extensive processing. Eukaryotic messenger RNA undergoes several modifications after transcription; it includes a 5' cap added for stability and recognition by ribosomes, a poly-A tail at the 3' end to protect against degradation, and splicing to remove non-coding sequences (introns) while keeping coding sequences (exons). These processes help ensure that only mature mRNA is translated into proteins in eukaryotic cells.
• Evaluate the significance of messenger RNA's role in biotechnology and genetic engineering.
  • Messenger RNA is fundamental in biotechnology and genetic engineering as it serves as a template for synthesizing proteins, including therapeutic proteins. By manipulating mRNA through techniques like in vitro transcription or employing messenger RNA vaccines, scientists can control protein expression for various applications. This ability to design specific mRNAs allows for targeted treatments in medicine and advancements in research, showcasing how crucial mRNA is in modern biological sciences and its potential in innovative therapies.

Related terms

Transcription: The process by which genetic information encoded in DNA is copied into messenger RNA.

Ribosome: A cellular structure that facilitates the translation of messenger RNA into a protein by reading the sequence of codons.

Translation:

The process in which the sequence of nucleotides in messenger RNA is translated into a specific sequence of amino acids to form a protein.