Last time [LINK] I talked about cells and DNA and we covered some amazing facts like how many cells there are in the body (100 trillion) and how in each the human genome there are 3 billion instructions or base pairs. Amazing stuff.  This time I want to cover what DNA does. Why it the building block of all life? Again, this info is relatively new to me and some of it is probably wrong.

So DNA is sitting in the nucleus. It’s organized into chromosomes. A chromosome is essentially a big bunch of DNA. In each chromosome there are many genes and remember each gene is nothing but a string of base pairs.  There are 46 different chromosomes and they come in pairs so you get 23 in a human. They are not literally shaped as X’s and Y’s. Here’s a snap shot for a MALE:

Roughly the LONG things are X chromosomes and the short ones are Y chromosomes. So you see the last one, number 23 has 1 X and 1 Y in a male. In a female this’d be two X’s.

Each chromosome has many genes, example is chromosome 1 has roughly 4300 genes and obviously a LOT of base pairs.

Now we know everything’s made from protein. What’s protein made from? and how is protein made? Protein is a sequence of amino acids. Amino acids are a collection of nucleotides, base pairs. Remember there are 20 total. So when you take a Gene, it has the information on how to make a protein.

Imagine the DNA double helix. This thing splits down the middle and gets copied or "transcribed" into a single strand called "RNA". This strand is smaller than the DNA and can fit through the nucleus membrane and get to a thing called a "ribosome’ which is outside the nucleus but inside the cell.

The Ribosome takes this RNA and processes it, like a big piece of tape going through a cassette player and as it goes the ribosome constructs a new piece of protein which then wanders off into the rest of the body.

So you can see, the instructions are critical to making the right protein.

Next up, what happens when things go wrong?