Biological Systems MCAT Practice Exam

Which process is characterized by the formation of the neural tube from the ectoderm?

1. Gastrulation

2. Neurulation

3. Fertilization

4. Implantation

The correct answer is: Neurulation

The formation of the neural tube from the ectoderm is a key developmental process known as neurulation. This occurs after gastrulation, during which the three primary germ layers—ectoderm, mesoderm, and endoderm—are formed. Neurulation specifically involves the folding and closure of the neural plate, which is derived from the ectoderm, to create the neural tube. The neural tube eventually develops into the central nervous system, which includes the brain and spinal cord. Gastrulation is a prior event that lays the groundwork for neurulation by establishing the body plan and germ layers, but it does not involve the formation of the neural tube itself. Fertilization is the process of combining sperm and egg to form a zygote, while implantation refers to the embedding of the fertilized egg into the uterine wall. Neither fertilization nor implantation involves the development of the neural structures. Thus, the process uniquely associated with the formation of the neural tube from the ectoderm is neurulation, making it the correct answer.