Protein synthesis

Definition

Protein synthesis is the biological process in which cells generate new proteins, essential for various functions within living organisms. This process involves two main stages: transcription, where the DNA sequence is copied into messenger RNA (mRNA), and translation, where the mRNA is used as a template to build a protein by linking amino acids together. It connects the genetic information encoded in DNA to the functional molecules that carry out vital tasks in cells.

5 Must Know Facts For Your Next Test

1. Protein synthesis occurs in two main stages: transcription and translation, which together ensure the accurate production of proteins based on genetic information.
2. Transcription takes place in the nucleus, while translation occurs in the cytoplasm at the ribosomes.
3. mRNA carries the genetic code from DNA to ribosomes, where it directs the sequence of amino acids to form a protein.
4. The genetic code is read in sets of three nucleotides called codons, with each codon corresponding to a specific amino acid.
5. Initiation, elongation, and termination are key phases in the translation process, ensuring that proteins are synthesized correctly and efficiently.

Review Questions

• How do transcription and translation work together in protein synthesis?
  • Transcription and translation are two interconnected processes that facilitate protein synthesis. First, during transcription, the DNA sequence of a gene is transcribed into mRNA inside the nucleus. Once this mRNA is formed, it moves into the cytoplasm where translation occurs. In this phase, ribosomes read the mRNA sequence and translate it into a specific sequence of amino acids to create a functional protein.
• Discuss the role of ribosomes in the process of translation during protein synthesis.
  • Ribosomes play a crucial role in translation, acting as the site where mRNA is decoded to synthesize proteins. They consist of two subunits made up of ribosomal RNA (rRNA) and proteins. As the ribosome moves along the mRNA strand, it facilitates the binding of transfer RNA (tRNA) molecules, which bring specific amino acids that correspond to each codon on the mRNA. This assembly process continues until a complete polypeptide chain is formed.
• Evaluate how errors in protein synthesis can affect cellular functions and lead to disease.
  • Errors in protein synthesis can have significant consequences for cellular functions and overall health. If mistakes occur during transcription or translation, such as incorrect amino acids being incorporated into a protein or mutations affecting mRNA stability, the resulting proteins may be nonfunctional or misfolded. These dysfunctional proteins can disrupt normal cellular processes and contribute to various diseases, including genetic disorders like cystic fibrosis or conditions such as cancer, where altered protein production leads to uncontrolled cell growth.

Related terms

Transcription: The first step of protein synthesis where a specific segment of DNA is copied into mRNA.

Translation: The second step of protein synthesis where the mRNA is decoded by ribosomes to assemble amino acids into a polypeptide chain.

Ribosome:

A cellular structure composed of RNA and protein that facilitates the translation of mRNA into proteins.