Transcript:

So, in chemistry, there is this thing called chirality. So chirality means you can make a molecule that is right-handed, and then you can make a molecule that is exactly the same molecule except with left-handed but no amount of rotation can superimpose these two. This means that these two molecules are compositionally identical but structurally different. They are called... This property is called chirality. So when you synthesize these molecules in the lab, some of them are left-handed, some of them are right-handed except in life. Life is predominantly homochiral, which means of all the amino acids if you take, the large majority—in fact, 19 of the 20 primary amino acids—are left-handed. Naturally made sugar, sugar that is made biologically, is right-handed. DNA molecule, the beta version which is the most prominent, is a right-handed spiral. There are other versions of this. There's the A-DNA and there's the Z-DNA. The Z-DNA is a left-handed spiral. Even in life, we have chirality. All screws are right-handed threaded. You don't see a left-handed threaded screw. Righty tighty, lefty loosey. Chirality is important.