Lecture 06

• What types of RNA are involved in protein synthesis?

  mRNA, rRNA, tRNA
• How do mRNA, rRNA, and tRNA regulate protein synthesis?

  They facilitate the translation process
• Where does translation occur in a cell?

  In the cytoplasm
• What is the role of ribosomes in protein synthesis?

  They assemble amino acids into proteins

  
• What is the function of the smaller subunit of the ribosome?

  Detects mRNA that needs translation

  
• What does the larger subunit of the ribosome do?

  Catalyses formation of peptide bonds

  
• What are the binding sites for tRNA on the ribosome?

  E, P, and A sites

  
• What is the primary structure of tRNA?

  Nucleotide sequence

  
• What shape does the secondary structure of tRNA take?

  Cloverleaf shape

  
• What is the tertiary structure of tRNA?

  L shape formed by 3D folding

  
• What is the role of the anticodon in tRNA?

  Pairs with the codon in mRNA

  
• How does the codon-anticodon pairing work?

  5’ base of codon pairs with 3’ base of anticodon
• What is required for loading tRNA with an amino acid?

  Aminoacyl tRNA synthetase

  
• What checks the anticodon-codon interaction on the ribosome?

  The ribosome itself
• What is the role of rRNA in the ribosome?

  Provides enzymatic activity for peptide bond formation

  
• What initiates translation in eukaryotes?

  Small subunit binds to 5’ CAP of mRNA

  
• What happens after the small subunit binds to the mRNA in eukaryotic initiation?

  It moves to the first AUG in the P site

  
• What occurs during the elongation phase of translation?

  Amino acids are added to the polypeptide chain

  
• What are the stop codons in translation?

  UGA, UAA, UAG

  
• What happens when a stop codon is reached during translation?

  No tRNA enters, release factors enter

  
• What are post-translational modifications?

  Changes made to proteins after synthesis

  
• How are inhibitors of protein or RNA synthesis useful?

  They act as antibiotics
• What is the role of molecular chaperones?

  Assist in protein folding

  
• What is the function of the proteasome?

  Degrades unneeded or damaged proteins
• What is the summary of the translation process?

  • Multiple types of RNA regulate protein synthesis (mRNA, rRNA, tRNA)
  • Translation occurs in the cytoplasm on ribosomes
  • mRNA nucleotide sequence is read in codons
  • Each codon corresponds to one amino acid
  • The genetic code defines amino acid-codon correspondence
  • Regulation affects protein concentration through synthesis and degradation rates