Botulinum toxin is a substance that can cause paralysis in humans. The effects of the toxin are due to the blocking of a signaling molecule that is necessary for communication between nerve cells. The toxin most likely interferes with the normal functioning of a
(1) chromosome
(2) DNA molecule
(3) receptor (4) digestive hormone
This is a question from the Living Environment Regent test January 2018.
We should first define all of the answer choices to be able to eliminate and come up with the correct answer. Chromosome functions to carry the genetic information and contains DNA molecules. DNA molecules are the basic building blocks of chromosomes that serve to carry the genetic information. Receptor is a molecule on the surface of cells that receives signals from the extracellular environment and leads to the changes in the function of the cell. Receptors do not respond to all signals but rather to the signals that are specific to them. That is how signals traveling in our body have an effect only on specific organs and tissues. Digestive hormone is a signal that is passes to digestive system that influences it's digestive functions.
The question is talking about a toxin that results in the blocking of a signaling molecule and therefore leads to the absence of communication between nerve cells. The toxin will most likely interfere with choice 3, receptor, since if it binds to the receptor and does not allow the actual signaling molecule to bind, it prevents the signaling molecule from sending its message forward to the receptor.
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