History of immune system
At one point one cell swallowed another but did not devour it. Instead, these two cells started arguably the most successful partnership on Earth. The “inside cell” that we know as mitochondria today, specialized in making energy available for the host, while the “outside cell” offered protection and delivered free food. This enabled the new cell to grow in complexity and become more sophisticated.
Being ‘alive’
Something ‘alive’:
- has a metabolism. So it takes up nutrients from the outside and gets rid of internal garbage.
- It also responds to stimuli.
- And it grows, and can make more of itself.
Cells
Cell is the smallest unit of life.
Cell contains proteins, and organelles like nucleus.
Proteins consist of amino acids. The amount of possible proteus is crazy. There is a subset of useful ones though (around one in a million to billion), which we also don’t understand yet.
The way your cells know how to order/chain these amino acids to make proteins, is DNA. Since there are so many possibilities, there needs to be a recipe book for proteins. This is your personal DNA! You are a unique protein recipe book!
1% of your DNA is made up of sequences that are building manuals for proteins. These are called Genes. The rest is regulating which proteins are built when and how, and how many of them at which time.
The process of protein building in the body
The process inside a cell: special proteins read the information on the DNA string and convert it. This conversion is to Messenger RNA
mRNA is the language that our DNA uses to communicate orders
Then, the mRNA molecule is transported from the nucleus of the cell to another organelle. Namely to the protein production machinery called the Ribosome.
In here, the mRNA molecule is read and translated into amino acids that are then put together in the order inscribed into it.
Out comes a protein!
So: DNA is basically a bunch of code, with sections called genes, that are a protein-building and regulation manual for your cellular machinery. And this translates into all the features that are ‘you’.
Note that red blood cells (around 80% of your cells) don’t have a nucleus, but are filled with oxygen. So don’t contain DNA :)