Question

The prion hypothesis claims that a disease can be transmitted by an agent that contains

Answer 1

Prions are infectious proteinaceous particles that do not contain DNA or RNA. They can cause disease when the normal prion protein is misfolded into a denatured form. The rogue protein can induce more misfolding, leading to the production of more rogue proteins.

Step-by-step explanation:

Prions are infectious proteinaceous particles that are not viruses and do not contain nucleic acid. They are typically transmitted by exposure to and ingestion of infected nervous system tissues, tissue transplants, blood transfusions, or contaminated fomites. Prion proteins are normally found in a healthy brain tissue in a form called PrPC. However, if this protein is misfolded into a denatured form (Prpsc), it can cause disease. Although the exact function of PrPC is not currently understood, the protein folds into mostly alpha helices and binds copper. The rogue protein, on the other hand, folds predominantly into beta-pleated sheets and is resistant to proteolysis. In addition, Prpsc can induce PrPC to become misfolded and produce more rogue protein (Figure 26.18).

Answer 2

The prion hypothesis claims that a disease can be transmitted by an agent that contains misfolded proteins.

Step-by-step explanation:

The prion hypothesis is a groundbreaking concept in the field of molecular biology and neurology. According to this hypothesis, infectious agents responsible for certain diseases are not viruses or bacteria but rather misfolded proteins. Unlike traditional infectious agents, prions lack genetic material like DNA or RNA.

Instead, they are composed of abnormal isoforms of a normal cellular protein, typically a protein called PrP (prion protein). The misfolded PrP induces the conversion of normal PrP into its misfolded form, leading to the accumulation of these aberrant proteins in the brain.

The key mechanism behind the prion hypothesis is the ability of misfolded proteins to induce the misfolding of normal proteins through a template-assisted process. This results in the formation of aggregates and fibrils, leading to neurodegenerative diseases.

Examples of prion diseases include Creutzfeldt-Jakob disease (CJD) in humans and bovine spongiform encephalopathy (BSE or "mad cow disease") in cattle. The infectious nature of prions challenges conventional ideas about the transmission of diseases, as they lack genetic material and operate solely through protein-protein interactions.

In summary, the prion hypothesis proposes that diseases can be transmitted by misfolded proteins, challenging the traditional understanding of infectious agents. The ability of misfolded proteins to induce the misfolding of normal proteins highlights the unique and unconventional nature of prion diseases in the realm of infectious pathology.