Messenger RNA

Definition

Messenger RNA (mRNA) is a type of RNA that carries genetic information from DNA to the ribosomes, where proteins are synthesized. It plays a crucial role in the process of transcription and translation, serving as a template for protein synthesis. mRNA is synthesized during transcription and is essential for conveying the instructions encoded in the DNA to ensure proper gene expression.

5 Must Know Facts For Your Next Test

1. mRNA is synthesized in the nucleus during transcription, where it is created as a complementary strand to the DNA template.
2. Once synthesized, mRNA undergoes processing, including capping and polyadenylation, before it exits the nucleus to reach the ribosomes in the cytoplasm.
3. mRNA has a specific sequence of codons that dictate the order of amino acids in a protein, making it crucial for determining protein structure and function.
4. The lifespan of mRNA molecules varies, influencing how much protein is produced; some mRNAs are rapidly degraded while others can last for hours or days.
5. Mutations in mRNA can lead to the production of malfunctioning proteins, which can result in various diseases or disorders.

Review Questions

• How does messenger RNA contribute to the flow of genetic information from DNA to proteins?
  • Messenger RNA plays a vital role in conveying genetic information by acting as an intermediary between DNA and proteins. During transcription, mRNA is synthesized using DNA as a template, capturing the genetic code needed for protein production. After processing, mRNA leaves the nucleus and travels to ribosomes where translation occurs, ultimately leading to the synthesis of proteins based on the sequence of codons present in the mRNA.
• Discuss the steps involved in the processing of messenger RNA after its synthesis and before translation.
  • After messenger RNA is synthesized in the nucleus, it undergoes several key processing steps before it can be translated. These include 5' capping, where a modified guanine nucleotide is added to the beginning of the mRNA for stability and recognition by ribosomes. Next, polyadenylation occurs, where a tail of adenine nucleotides is added to the 3' end. Finally, splicing removes non-coding regions (introns) and joins together coding regions (exons), creating a mature mRNA molecule that can exit the nucleus and be translated into protein.
• Evaluate how mutations in messenger RNA can impact protein synthesis and cellular function.
  • Mutations in messenger RNA can lead to significant changes in protein synthesis and overall cellular function. For instance, if a mutation alters a codon within mRNA, it may lead to an incorrect amino acid being incorporated into a protein, potentially disrupting its structure and function. In some cases, mutations can introduce premature stop codons, resulting in truncated proteins that may be nonfunctional or harmful. Such changes can contribute to various diseases or disorders by affecting cellular processes critical for maintaining health.

Related terms

Transcription: The process by which the information in a segment of DNA is copied into messenger RNA.

Translation: The process by which the sequence of nucleotides in messenger RNA is used to synthesize a specific protein.

Ribosome: The molecular machine that facilitates the translation of messenger RNA into proteins, composed of ribosomal RNA and proteins.