Protein synthesis

Definition

Protein synthesis is the biological process in which cells generate new proteins based on the genetic information encoded in DNA. This process involves two main stages: transcription, where DNA is converted into messenger RNA (mRNA), and translation, where ribosomes use the mRNA to assemble amino acids into a polypeptide chain, ultimately forming functional proteins that play critical roles in the cell.

5 Must Know Facts For Your Next Test

1. Protein synthesis starts with transcription in the nucleus, where specific segments of DNA are transcribed into mRNA.
2. After transcription, mRNA travels from the nucleus to the cytoplasm, where ribosomes read the mRNA sequence during translation.
3. Each set of three nucleotides on mRNA, called a codon, corresponds to a specific amino acid or stop signal during protein synthesis.
4. Transfer RNA (tRNA) molecules bring amino acids to the ribosome and match them to the correct codon on the mRNA.
5. Post-translational modifications may occur after translation, which can affect protein folding, stability, and activity.

Review Questions

• How do transcription and translation work together in the process of protein synthesis?
  • Transcription and translation are two key steps in protein synthesis that work together seamlessly. First, during transcription, DNA is transcribed into messenger RNA (mRNA) in the nucleus. The mRNA then moves to the cytoplasm, where translation occurs; ribosomes read the mRNA sequence and assemble amino acids into a polypeptide chain according to the codons present in the mRNA. This collaboration ensures that genetic information is accurately converted into functional proteins.
• Discuss the role of ribosomes in protein synthesis and why they are essential for cellular function.
  • Ribosomes play a crucial role in protein synthesis as they are the sites where translation occurs. They consist of ribosomal RNA (rRNA) and proteins, forming a complex that facilitates the decoding of mRNA into a specific sequence of amino acids. Ribosomes are essential for cellular function because they produce proteins that are vital for numerous biological processes, including enzyme activity, structural support, and signaling pathways. Without ribosomes, cells would be unable to synthesize proteins necessary for life.
• Evaluate the impact of errors during protein synthesis and how they can affect cellular function.
  • Errors during protein synthesis can lead to incorrect amino acid sequences in proteins, potentially resulting in dysfunctional or nonfunctional proteins. These mistakes may arise from mutations in DNA affecting transcription or misreading of codons during translation. Such errors can disrupt critical cellular functions, leading to diseases or developmental issues. Understanding these impacts highlights the importance of accuracy in protein synthesis and mechanisms cells have in place for error-checking and correction.

Related terms

DNA:

Deoxyribonucleic acid, the molecule that carries the genetic instructions for the development, functioning, growth, and reproduction of all known organisms.

RNA: Ribonucleic acid, a nucleic acid involved in various biological roles, primarily as a messenger carrying instructions from DNA for controlling the synthesis of proteins.

ribosome: A complex molecular machine found within all living cells that assembles proteins by translating messenger RNA (mRNA) sequences into polypeptide chains.