EasyBiologyHigh School (11–12)Diversity of Living Organisms › Viruses, Viroids and PrionsNumericalBoard Exam
Nine viruses are listed with their genetic material…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Nine viruses are listed with their genetic material. Poliovirus, measles virus, rabies virus, dengue virus and rotavirus have RNA. Hepatitis B virus, chickenpox virus, adenovirus and phage T4 have DNA. How many have RNA, and how many have DNA? Can one virus have both?
Need a reminder? The key ideaShow
Viruses, viroids and prions are not in the five kingdoms. A virus is an obligate parasite: DNA or RNA, never both, inside a protein capsid. Ivanowsky (1892) found that the cause of tobacco mosaic passed through a bacterial filter; Beijerinck (1898) called it Contagium vivum fluidum; Stanley (1935) crystallised the virus. Diener (1971) found the viroid, free RNA with no coat. A prion is an abnormally folded protein (BSE, CJD).
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. RNA. Poliovirus, measles, rabies, dengue and rotavirus: .
Step 2. DNA. Hepatitis B, chickenpox, adenovirus and phage T4: .
Step 3. Both? No. A virus has either DNA or RNA, never both.
Answer: RNA viruses and DNA viruses; never both in one virus.
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