True about prions is
**Core Concept**
Prions are infectious proteins that cause fatal neurodegenerative diseases in animals, including humans. They are unique in that they are the only infectious agents that do not contain nucleic acids (DNA or RNA). Prions propagate by transmitting their misfolded protein structure to normal proteins, leading to a chain reaction of misfolding.
**Why the Correct Answer is Right**
The correct answer is related to the mechanism of prion transmission. Prions are highly resistant to heat, radiation, and chemicals, which makes them difficult to inactivate. They can withstand temperatures up to 300°C (572°F) for an extended period and can survive for years in the environment. This resistance is due to their unique protein structure, which allows them to maintain their infectious properties even in the absence of nucleic acids.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the unique characteristics of prions. While prions are indeed infectious, this option does not capture their distinctiveness from other infectious agents.
**Option B:** This option is incorrect because it is not a recognized property of prions. Prions do not have a known function in normal cellular processes, and their transmission is not related to their supposed function.
**Option C:** This option is incorrect because it is not a characteristic of prions. Prions are not viruses, and they do not contain nucleic acids.
**Option D:** This option is incorrect because it is not a property of prions. While prions can cause disease, this option does not accurately describe their unique characteristics.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that prions are the only infectious agents that can be transmitted without nucleic acids. This makes them unique and difficult to diagnose, as standard microbiological tests will not detect them. Prion diseases, such as Creutzfeldt-Jakob disease, are often fatal and have a long incubation period.
**Correct Answer: C. Prions are infectious proteins that do not contain nucleic acids.**