Which one of the following statements is correct?
- APrions are the smallest free-living cells
- BThe cell wall of Mycoplasmas is made up of amino sugars
- CViroids consist of a single stranded RNA moleculeCorrect
- DRickettsia’s lack cell wall
Explanation
Option C is correct because viroids are infectious agents that are even smaller than viruses and consist solely of a short, circular, single stranded RNA molecule without a protein coat.
The other options are incorrect for the following reasons: Prions are not cells but are infectious misfolded proteins that do not contain genetic material. Mycoplasmas are unique because they completely lack a cell wall, making them resistant to many antibiotics. Rickettsias are a group of bacteria that do possess a true cell wall, similar to other gram negative bacteria.
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