A Primer on Genetic Circuits
The Central Dogma of Genetics

Adapted from BioNinja

DNA

Almost each one your cells contains DNA, which is just a long string of molecules called nucleotides that look like this:

Adapted from Wikipedia

There are 4 types of nucleotides that make up DNA, each one characterized by its nitrogenous base component: adenosine, thymine, cytosine, and guanine — aka A, T, C, and G.

These bases come in binding (or complementary) pairs — A will only bind with T, C with G.

A specific sequence of these nucleotides is called a gene. Genes are kind of like commands for a computer; they tell the cell what protein to make.

RNA

RNA is very similar to DNA — except it’s only one stranded and it contains uracil nucleotides instead of thymine. RNA can also form more complicated machinery like ribosomes, which we’ll bring up later.

An enzyme (basically a molecular machine) called RNA polymerase will ‘read’ a gene nucleotide by nucleotide.

While it does this, it collects free complementary nucleotides to string together a strand of messenger RNA, or mRNA — sort of like making an inverse copy.

Proteins

Proteins are big molecules that perform some kind of function. They’re made up of smaller molecules called amino acids, which look like this:

From Sielc | “R” isn’t an element, but is a placeholder for various other types of molecular structures.

Amino acid sequences are very specific, and they’re determined by genes. RNA machines called ribosomes will read the nucleotide sequence of mRNA and use it to string AAs together into a strand (aka a polypeptide).

How? Every amino acid corresponds to one or more three-nucleotide sequence s— aka a codon.

Amino acids will interact with one another, all while being influenced by their chemical environment. This leads to the polypeptide folding into a 3-D structure — a protein. Proteins can fight viruses, induce movement, turn other proteins on or off. If you can control proteins, you can control the cell.
['Murto Hilali']
['Biology', 'Science', 'Technology', 'Podcast', 'Genetics']