Question

Explain why cadmium and mercury are toxic to most organisms.

Short answer

Cadmium and mercury can act as substitutes for zinc, disrupting functions controlled by zinc fingers.

Step-by-step solution

Cadmium

Chemical element cadmium has the atomic number and the letter Cd assigned to it. The two other stable metals in group —mercury and zinc—have chemical properties that are comparable to this delicate, silvery-white metal.

Explanation

Cadmium and mercury are heavy metals that belong to the same chemical family as zinc.

The zinc finger motif, which is vital for the function of many proteins, is formed by zinc, an essential cofactor. Because zinc fingers cannot work with any other ion, cadmium or mercury ions that can take the place of zinc prevent zinc fingers from functioning, rendering them hazardous.

Hence, mercury and cadmium are toxic to organisms.