Q47.2-2CC. - Campbell Biology

Question

WHAT IF? Predict what would happen if, just before neural tube formation, you treated frog embryos with a drug that enters all the cells of the embryo and blocks the function of microfilaments.

Step-by-Step Solution

Answer

When the embryo of a frog is treated before neural tube formation, it can hinder the functioning of the microtubules. The contractions of the microtubules would reduce, and hence the size of one side of the cell would reduce. 

Due to this, hinge functions and bending of the neural tube would not occur; thus, the neural tube does not form.

Step 1: Neurulation

Neurulation is a process during the development of the frog embryo in which the mesodermal cells in the dorsal region give rise to the notochord. The mesodermal cells also produce signaling molecules that initiate the neural plate synthesis from the ectoderm that covers the notochord.

Step 2: Neural tube formation in frogs

The neural plate changes its structure through inward folding to produce the neural tube that extends from the anterior end to the posterior end of the frog. As the development proceeds, this neural tube gives rise to the brain and the spinal cord.

Step 3:Effects of drugs on neural tube formation

When drugs are administered into the embryo of the frog before the neural tube is formed, it can block the functioning of the microfilaments. The contractions of the microtubules reduce significantly, and therefore, the folding of the neural plate does not occur, and the neural tube does not form.