AP BIOLOGY

Detailed explanation-1: -Prions are an aggregate of proteins that have folded incorrectly. They are transmissible and cannot be broken down by our cells and therefore usually lead to the death of the cell. In Creutzfeldt-Jakob disease, a protein found in the brain called PrP misfolds and forms PrP-sc.

Detailed explanation-2: -Prions represent a group of proteins with a unique capacity to fold into different conformations. One isoform is rich in beta-pleated sheets and can aggregate into amyloid that may be pathogenic. This abnormal form propagates itself by imposing its confirmation on the homologous normal host cell protein.

Detailed explanation-3: -The abnormal folding of the prion proteins leads to brain damage and the characteristic signs and symptoms of the disease. Prion diseases are usually rapidly progressive and always fatal.

Detailed explanation-4: -The misfolding and aggregation of the human prion protein (PrP) is associated with a number of fatal neurodegenerative disorders designated as transmissible spongiform encephalopathies (TSEs), including Kuru, Creutzfeldt–Jakob disease, fatal familial insomnia, and mad cow disease (1).

Detailed explanation-5: -Prion proteins are normally found in all mammalian brains, but it is believed that altered forms of these proteins fold abnormally as a result of a mutations; as a result the proteins encoded by the mutant genes have distorted shapes, and they are not broken down normally.