I understand that prions are folded proteins that cause infectious diseases in the brains of mammals.
**Some questions on top of the **
1. So don’t eat mammal brains in case of prions – does this mean all mammals have prions in their brains?
2. If I ate a mammal brain and got a prion disease, is it possible that that mammal doesn’t have the disease?
3. Is it the prions themselves that are infectious, or the diseases they cause that are?
4. How do the prions cause the diseases?
In: Biology
Proteins are sequences of smaller chemical blocks (called “amino acids”). The order of these blocks matters a LOT, because they can interact with each other in a lot of special, and VERY complicated, ways. These interactions define how the protein “folds” once it is made. The way a protein is folded is what causes that protein to do the chemical things it does. (This is also why cooking causes proteins to break down: you add enough energy to partly un-fold the proteins.)
Sometimes, proteins can fold incorrectly, which makes them not work right anymore. Usually, this doesn’t matter and the creature’s body will just break the defective protein down to build something else. Unfortunately, in very rare cases, some proteins fold wrong and it causes problems–the new way it’s folded up does bad things to the cells it’s in. Prions are proteins that have a special, *extremely* bad wrong folding, which doesn’t just cause problems by itself–it actually can make OTHER copies of that protein *change* into the wrong version.
When this happens to an essential protein, it can destroy cells and ruin organs. It just happens to be the case that one particular prion is a protein that is essential for brain cells to have the structure they need. The prion version of that protein breaks that structure. When you look at the brain tissue under a microscope, it looks like it’s full of holes. This is why the official name for “mad cow disease” is “bovine spongiform encephalopathy” — literally “sponge-like cow brain disease.”
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