Answer:
The answer to the question: What effect will the decreased iron availability have on the production of diphteria toxin, would be, A: The lack of co-repressor binding to DtxR will lead to a loss of repression and an increase in the production of toxin.
Explanation:
Diphteria is a very serious disease that is caused by the gram-negative bacteria Corynebacterium Diphtheriae, which attacks the upper respiratory tract, especially the throat, and causes a thick lining to form, complicating the normal respiratory function. In order to accomplish such a feat, this bacteria produces a toxin that attacks human cells. But the toxin will not be produced if there is a high availability of iron in the area where the bacteria intends to infect, because if that is the case, then iron will work as a co-repressor with DtxR to prevent the expression of the bacterial gene that codes for the toxin. A co-repressor means that iron will work as a coadjuvant for DtxR and will not allow the genes of the bacteria to produce the toxin. In the case of this question, the answer is A because we have a lack of iron availability, which means that DtxR will not be enough to stop the toxin from being produced.