Protein synthesis

• What is the process of protein synthesis primarily about?

  The making of proteins from polypeptide chains
• Where does the first stage of protein synthesis occur?

  Inside the nucleus
• What is transcription in the context of protein synthesis?

  It is the process where a gene is copied into mRNA
• What is the role of mRNA in protein synthesis?

  To carry the genetic information from DNA to the ribosome
• Why can't DNA leave the nucleus during protein synthesis?

  Because DNA is too big to fit through nuclear pores
• What is the first step of transcription?

  To create a copy of the gene of interest on the DNA
• What enzyme is used to unwind the DNA double helix during transcription?

  DNA helicase
• What happens to the RNA nucleotides during transcription?

  They align opposite their complementary base pairs on the exposed DNA strand
• What is the term for the initial form of mRNA before modifications?

  Pre-mRNA
• What is splicing in the context of mRNA processing?

  It is the removal of introns from pre-mRNA
• What are introns?

  Sequences of bases in DNA that do not code for amino acids
• What is the role of a spliceosome?

  To remove introns from pre-mRNA
• What happens to the mRNA after splicing?

  It consists only of exons and is ready to leave the nucleus
• What is the second stage of protein synthesis called?

  Translation
• What occurs during translation?

  The polypeptide chain is created from mRNA and tRNA
• What is the start codon in mRNA?

  The first three bases at the start of the sequence
• What is the function of tRNA during translation?

  To bring specific amino acids that match the codons on the mRNA
• How does the ribosome facilitate translation?

  It holds the mRNA and tRNA in place
• What is created when two amino acids join together?

  A peptide bond
• What is required to create a peptide bond between amino acids?

  An enzyme and ATP
• What happens when the ribosome reaches a stop codon?

  The ribosome detaches from the mRNA, ending translation
• What is the final product of translation?

  A finished polypeptide chain
• Where does the polypeptide chain go after translation?

  To the Golgi body for folding and modifications
• What are the key steps in protein synthesis?

  1. Transcription: DNA is copied into mRNA in the nucleus.
  2. mRNA processing: Introns are spliced out, and exons are joined.
  3. Translation: mRNA is translated into a polypeptide chain at the ribosome.
• What are the roles of introns and exons in protein synthesis?

  • Introns: Non-coding regions removed during mRNA processing.
  • Exons: Coding regions that remain in the final mRNA.
• What is the significance of the start and stop codons in translation?

  • Start codon: Signals the beginning of translation.
  • Stop codon: Signals the end of translation and causes ribosome detachment.
• What is the role of ATP in protein synthesis?

  • Provides energy for the formation of peptide bonds during translation.
• How does the ribosome function during translation?

  • Holds mRNA and tRNA in place.
  • Facilitates the joining of amino acids to form a polypeptide chain.