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How does an incoming PrPsc molecule multiply itself inside the body?
AIt is copied by a host RNA polymerase
BIt splits in two like a bacterial cell
CIt binds PrPc and converts it to PrPsc
DIt orders ribosomes to make more PrPsc
Answer & Solution
Correct answer: C. It binds PrPc and converts it to PrPsc
1. The prion protein PrP exists in two forms, the normal PrPc and the infectious PrPsc.
2. Once introduced into the body, the PrPsc inside the prion binds to PrPc.
3. Binding converts that normal molecule into the infectious form.
4. Each new PrPsc can convert another PrPc, so the amount rises exponentially and the protein aggregates.
5. PrPsc is folded abnormally, and that shape is directly responsible for the brain lesions.
6. No polymerase and no ribosome is involved, since the prion carries no gene of its own, which rules out two options.
7. Splitting in two is cell division, and a protein particle cannot divide, so that option is not possible.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 21 "Viruses", section 21.4 Other Acellular Entities: Prions and Viroids_
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