Refer to the treatments listed below to answer the following questions.
You isolate an infectious substance that is capable of causing disease in plants, but you do not
know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods
at your disposal that you can use to analyze the substance in order to determine the nature of the
I. treating the substance with nucleases that destroy all nucleic acids and then determining
whether it is still infectious
II. filtering the substance to remove all elements smaller than what can be easily seen under
a light microscope
III. culturing the substance by itself on nutritive medium, away from any plant cells
IV. treating the sample with proteases that digest all proteins and then determining whether it
is still infectious
23) Which treatment could definitively determine whether or not the component is a viroid?
E) first II and then III