Protein Synthesis

Stated Clearly presents: What is DNA and how does it work?

DNA, also known as deoxyribonucleic acid, is a molecule. It’s a bunch of atoms stuck together.

In the case of DNA, these atoms combined to form the shape of a long spiraling ladder – sort of like this one here. If you ever studied biology or saw the movie Jurassic Park, you probably heard that DNA acts as a blueprint or recipe for a 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? [Yelp!]

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’s about twenty different kinds, each with their own unique shape. The neat thing about them is they can be attached to each other, kind of like Legos, to produce an endless variety of larger particles known as proteins.

Amino acids make up proteins. Proteins, along with other chemicals, combine to form living cells. Cells make up tissues. Tissues make up organs. And organs, when they’re all put together and functioning of course, combine 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. [Hoot!]

This here is a simplified model of DNA. It shows us that the steps of the ladder are made up of four different kinds of chemicals shown here by different colors and letters. If you look at just one half of the molecule, you can read this chemical sequence, or genetic code, from top to bottom, sort of like a book. 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 centerpiece 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 allows 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, and stick them together in a chain according to the RNA 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 can then go on to do a number of different things, one of which could be to help form a brand new cell.

So to answer the original question, “What is DNA?” DNA is a molecular blueprint for a living thing. How does it work? DNA creates RNA, RNA creates protein, proteins go on to form life.

This entire process – as complicated, as sophisticated, as magical as it might seem – is entirely based in chemistry. It can be studied. It can be understood.

I’m Jon Perry and that’s DNA Stated Clearly.