3 ms·

In the way that molecules are so fast that they go past each other frequently, making global effects possible to arise from small perturbations.

acjohnson55 5y ago
One thing that comes to mind is prions, which cause diseases like mad cow and CJD. "Prions are misfolded proteins with the ability to transmit their misfolded shape onto normal variants of the same protein." https://en.m.wikipedia.org/wiki/Prion https://en.m.wikipedia.org/wiki/Prion
- icoder 5y ago
  I think you and parent came up with a possibly better example than the one in the article quoted by the grandparent comment, more so than it being a clarification of how single DNA mutations ripple out to be big problems.
gus_massa 5y ago
That's incorrect. Molecules collide when they are close enough. (There is a small probability of tunneling, but it's really small.) Small perturbations in a crystal are call "defects" https://en.wikipedia.org/wiki/Crystallographic_defect https://en.wikipedia.org/wiki/Crystallographic_defect and they are quite stable, and don't move too much. The effect is very local. The defects in DNA can have a huge effect if they are in an (un)lucky spot, and they are completely unrelated to material science.
- trutannus 5y ago
  Basically, insofar as the perturbation does not impact more than the local lattice structure (sometimes just a few NM across), the overall lattice (therefore properties) will be rather unaffected. I know pure crystals will often have embedded impurities (ie: precursor residues in the product). The impact for the DNA change is that DNA is used to create downstream materials, whereas materials are generally used because of their properties directly. As long as a defect does not impact to a great extent the general properties of the material, it is irrelevant. In terms of movement inside a lattice structure, the only real movement is vibrational and rotational movement, so global effects because of particles moving about has far lower influence.
- DrJokepu 5y ago
  Depends on the type of defect. Dislocations can move around quite a bit and they do affect the structural integrity of the material. This is why if you bend a fork, you will never be able to fully unbend it (without heat treatment), there will always be a S-shaped bend it it.
- kragen 5y ago
  an iron whisker with a single crystal defect in it has dramatically different macroscopic properties, especially tensile strength, from an iron whisker without a single crystal defect.

acjohnson55 5y ago

One thing that comes to mind is prions, which cause diseases like mad cow and CJD. "Prions are misfolded proteins with the ability to transmit their misfolded shape onto normal variants of the same protein." https://en.m.wikipedia.org/wiki/Prion https://en.m.wikipedia.org/wiki/Prion

icoder 5y ago
I think you and parent came up with a possibly better example than the one in the article quoted by the grandparent comment, more so than it being a clarification of how single DNA mutations ripple out to be big problems.

gus_massa 5y ago

That's incorrect. Molecules collide when they are close enough. (There is a small probability of tunneling, but it's really small.) Small perturbations in a crystal are call "defects" https://en.wikipedia.org/wiki/Crystallographic_defect https://en.wikipedia.org/wiki/Crystallographic_defect and they are quite stable, and don't move too much. The effect is very local. The defects in DNA can have a huge effect if they are in an (un)lucky spot, and they are completely unrelated to material science.

trutannus 5y ago
Basically, insofar as the perturbation does not impact more than the local lattice structure (sometimes just a few NM across), the overall lattice (therefore properties) will be rather unaffected. I know pure crystals will often have embedded impurities (ie: precursor residues in the product). The impact for the DNA change is that DNA is used to create downstream materials, whereas materials are generally used because of their properties directly. As long as a defect does not impact to a great extent the general properties of the material, it is irrelevant. In terms of movement inside a lattice structure, the only real movement is vibrational and rotational movement, so global effects because of particles moving about has far lower influence.
DrJokepu 5y ago
Depends on the type of defect. Dislocations can move around quite a bit and they do affect the structural integrity of the material. This is why if you bend a fork, you will never be able to fully unbend it (without heat treatment), there will always be a S-shaped bend it it.
kragen 5y ago
an iron whisker with a single crystal defect in it has dramatically different macroscopic properties, especially tensile strength, from an iron whisker without a single crystal defect.