FactReactorYou Are Made Of One Chirality
Watch on YouTubeHold up both hands. They are the same shape built twice, and they will never stack, because one is simply the mirror of the other.
That refusal goes all the way down. Molecules are handed too. A mirror twin has every atom in the same place and every bond the same length, and it still will not overlay on the original.
Your body picked one side and only ever builds on that side. Every protein you have ever made was assembled from left-handed pieces, and your ribosome will not accept the other one.
Which means half of all possible chemistry is food you can look at, smell, even taste, and never actually use. Mirror sugar still tastes sweet, because the sweet sensor on your tongue cannot tell the two apart. Your tongue is fooled. Your metabolism is not - your body gets almost nothing out of it.
A mirrored copy of you would sit down at a full table and slowly starve, because nothing on it would fit.
Now hold up both hands.
Sources:
https://en.wikipedia.org/wiki/Homochirality
https://en.wikipedia.org/wiki/L-Glucose
https://en.wikipedia.org/wiki/Carvone
Clarification
One correction before somebody else makes it, because it is a first-year chemistry fact: it is NOT true that every molecule in you is left-handed. D-amino acids are real and they are in you - D-alanine and D-glutamate in bacterial cell walls, D-amino acids acting as signalling molecules in your brain. The airtight version is the one the video actually says: every *protein* you have ever built was assembled from the left-handed set, because your ribosome will not take the other one. Narrower, and stranger.