DNA also known as deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. It’s a bunch of atoms stuck together. In the case of DNA, these atoms combined to form the shape of a long spiralling ladder. If you ever studied biology, you probably heard that DNA acts as a blueprint or recipe for living thing, but how? How on earth can a mere molecule act as a blueprint for something as complex and wonderful as a tree a dog or a dinosaur? To help answer that question let’s first take a quick look at amino acids.
Amino acids are tiny little chemicals inside our bodies that are so important. They’re often referred to as the building blocks of life. There are about twenty different kinds each with their own unique shape. The cool thing about them is they can be attached to each other kind of like Legos to produce an endless variety of larger particles called proteins. Amino acids make up proteins, proteins along with other chemicals combined to form living cells, cells make up tissues, tissues make up organs. And organs, when they’re all put together and functioning of course, combined to form living creatures like you and me.
These proteins that make up our bodies, and keep in mind there’s millions of different kinds of proteins, they each have to be formed in the perfect shape in order to function. If they are the wrong shape they usually won’t work, that’s where DNA comes in. DNA does a lot of interesting things some of which we don’t fully understand, but one of its main and most well understood functions is to tell amino acids how to line up and form themselves into the perfect protein shapes. In theory if the right proteins are built at the right time and in the right place, everything else from cells to organs to entire creatures will come out just fine.
A single strand of DNA is extremely long millions of letters long. It spends most of its life coiled up like a noodle living inside the nucleus or the centrepiece of a cell. Amino acids however live outside the nucleus in what’s called the cytoplasm to help DNA interact with the cytoplasm and convert those amino acids into proteins. Special chemicals inside the nucleus make partial copies of the DNA code. These partial copies called RNA look a lot like DNA but they’re shorter of course and they’re missing one of their sides. Their small shape and size allow them to fit through tiny pores in the nucleus out to the cytoplasm and into the mouth of another particle called a ribosome.
Ribosomes are protein building machines. They read the RNA code three letters at a time, suck amino acids out of their surroundings stick them together in a chain according to the genetic code as a chain grows it bends, folds, and sticks to itself to form a perfectly shaped protein. Every three letters of the RNA code tell the ribosome which of the twenty different kinds of amino acids should be added next. For example, CAA tells the ribosome to grab a glutamine, AGU tells it to grab a serine and so on. Once a protein is built it then goes on to do a number of different things, one of which could be to help form a brand new cell.