[Campbell Biology P.1111] Based on the Spemann-Mangold experiment, which of the following sta... | Practice Question

Based on the Spemann-Mangold experiment, which of the following statements best describes the function of the dorsal lip of the blastopore?

  • A: It functions as a pluripotent stem cell source that directly differentiates into all parts of a secondary embryo.
  • B: It is primarily responsible for inhibiting neural tube formation in the developing embryo.
  • C: It acts as an "organizer" by inducing surrounding cells to change their developmental fate, partially through inactivating BMP-4, which allows the formation of dorsal structures like the notochord and neural tube.
  • D: It secretes Fibroblast Growth Factor (FGF) to promote the proximal-distal outgrowth of limb buds.

Explanation

The Spemann-Mangold experiment demonstrated that the dorsal lip of the blastopore acts as an "organizer" that induces surrounding tissues to form structures they wouldn't normally form, such as a secondary notochord and neural tube, leading to a twinned embryo. The text further explains that this function involves inactivating BMP-4 on the dorsal side, allowing for dorsal structure formation.