[Campbell Biology P.428] According to the text, once an mRNA encoding a particular protein r... | Practice Question

According to the text, once an mRNA encoding a particular protein reaches the cytoplasm, which of the following mechanisms can regulate the amount of the active protein in the cell? Select all that apply

  • A: Processing of eukaryotic polypeptides into functional molecules (e.g., pro-insulin cleavage)
  • B: Chemical modifications of proteins (e.g., addition of phosphate groups)
  • C: Transport of proteins to target destinations
  • D: Selective degradation of proteins (e.g., via ubiquitin-proteasome system)
  • E: Transcription factor binding to promoter regions

Explanation

The section 'Protein Processing and Degradation' describes 'the final opportunities for controlling gene expression occur after translation'. These include: 1. Eukaryotic polypeptides being processed e.g., pro-insulin cleavage Option A . 2. Many proteins undergoing chemical modifications e.g., phosphate groups Option B . 3. Cell-surface proteins and many others being transported to target destinations Option C . 4. Selective degradation of proteins e.g., ubiquitin-proteasome system Option D . Option E, transcription factor binding, is a pre-translational control mechanism.