IRC highlights!

Well, ribosomes (the cellular machine that, via translation, makes a tangible product out of lines of code) produce a polypeptide according to the mRNA sequence that got fed through them.

The polypeptide is a chain of amino acids, and amino acids are just molecules. Different points in the chain have different dangly bits, different regions that repel or attract and generally restrict the polypeptide from scrunching up however the fuck it pleases.

The specific chemical/atomic/molecular properties of the polypeptide chain (similar properties that cause water and oil to not mix unless you add soap) will dictate how it folds up, kind of like how:

are the exact lines you fold in a sheet of paper to produce a cup which Actually Holds Real Water. Put seven creases in different positions on the paper and you're either going to get something Less Good At Holding Water, something which Can't Hold Water For Shit, or maybe even something That Does Something Really Good That Isn't Holding Water*.

To distort the metaphor somewhat for the sake of scientific clarity, imagine photocopying something 3-dimensional (butt, face, artfully arranged collection of office stationery) then folding along the lines on the resulting 2-dimensional printout. Most of the time, according to your rules (in the photocopier metaphor, artistic license and consistent decisions about what constitutes a "fold line"; in gene expression, chemical/physical properties like activation energy/hydrophilic or -phobic regions), you're just going to get crumpled-up bullshit. Photocopy a cup and you're not going to get a piece of paper that intuitively folds into a cup.


*Obviously, in origami, the order in which you make the creases is just as important - this applies somewhat to proteins too; many "organelles" in the cell (chiefly the golgi bodies, and the rough and smooth endoplasmic reticulums) act as micro-"climates" that make certain amino acids in the chain more or less disposed to repel/attract, or certain regions to end up on the "inside" or "outside" of the resulting molecule.