MRNA

Definition

mRNA, or messenger RNA, is a single-stranded nucleic acid that carries genetic information from DNA to the ribosome, where proteins are synthesized. This process, known as transcription and translation, is crucial for cellular function as mRNA serves as a template that dictates the amino acid sequence of proteins, which are essential for various cellular processes and functions.

5 Must Know Facts For Your Next Test

1. mRNA is synthesized in the nucleus during transcription, where a specific segment of DNA is copied into a complementary RNA strand.
2. After synthesis, mRNA undergoes processing, which includes capping, polyadenylation, and splicing to create a mature mRNA molecule ready for translation.
3. mRNA has a relatively short lifespan in the cell, which allows for precise regulation of gene expression based on the cell's needs.
4. Each mRNA molecule corresponds to a specific gene and contains codons, sequences of three nucleotides that specify which amino acids will be added during protein synthesis.
5. Mutations in mRNA can lead to the production of faulty proteins, which may result in various diseases and disorders affecting cellular function.

Review Questions

• How does mRNA play a role in the process of protein synthesis within the cell?
  • mRNA serves as the intermediary between DNA and protein synthesis. It is transcribed from DNA in the nucleus and carries genetic information to the ribosome, where it guides the assembly of amino acids into proteins. The ribosome reads the codons on the mRNA, using tRNA to bring in the appropriate amino acids, ensuring that proteins are synthesized accurately according to genetic instructions.
• What are the key steps involved in the processing of mRNA after it is synthesized from DNA?
  • After mRNA is synthesized through transcription, it undergoes several crucial processing steps before it can be translated into protein. These steps include adding a 5' cap and a poly-A tail to protect the mRNA from degradation and facilitate its export from the nucleus. Additionally, introns are spliced out, leaving only exons, which are coding sequences that will be used during translation. This maturation process ensures that only functional mRNA is translated into proteins.
• Evaluate the impact of mutations in mRNA on protein synthesis and cellular function.
  • Mutations in mRNA can have significant consequences for protein synthesis and overall cellular function. Such mutations may alter codons in ways that change amino acids in the resulting protein or even introduce premature stop codons. This can lead to dysfunctional proteins that do not perform their intended roles within the cell or disrupt normal cellular processes. The resulting imbalance or malfunction can contribute to various diseases, highlighting the importance of accurate mRNA transcription and processing.

Related terms

DNA: Deoxyribonucleic acid, the molecule that carries the genetic instructions for life in all living organisms.

Ribosome: A cellular structure composed of RNA and proteins that facilitates the translation of mRNA into a polypeptide chain, ultimately forming proteins.

tRNA: Transfer RNA, a type of RNA that transports amino acids to the ribosome during protein synthesis according to the sequence specified by the mRNA.