[Campbell Biology P.433] According to Figure 18.18, which of the following statements accura... | Practice Question

According to Figure 18.18, which of the following statements accurately describes the role of MyoD protein in muscle cell development?

  • A: MyoD protein is primarily responsible for turning off the myoD gene after determination is complete.
  • B: MyoD acts as a transcription factor that activates its own gene and other muscle-specific genes, as well as genes that block the cell cycle.
  • C: MyoD protein directly fuses myoblasts into mature muscle fibers.
  • D: MyoD protein is only involved in the initial determination phase and has no role in the subsequent differentiation process.

Explanation

This question tests the understanding of the dual role of MyoD protein as a master regulatory transcription factor. It initiates determination by activating its own gene feedback loop and drives differentiation by activating other muscle-specific genes and genes that arrest the cell cycle, leading to myoblast fusion and muscle fiber formation.