Imagine that you had a cookbook with the best recipes of your grandparents and other ancestors. It’s very important to you and you don’t want to damage it, but you want to use one of the recipes. What would you do? You’d probably copy the recipe you needed and keep the original cookbook in a safe place.

Why am I talking about cookbooks? Well, your complete set of DNA, your genome, is basically a set of recipes passed down to you from your ancestors. Almost every one of your cells has a complete copy of the genome in its nucleus. It stays safe in the nucleus all the time unless the cell is dividing. But the cellular machinery that “reads” the “recipes” to make proteins are out in the cytoplasm. So how do you get the code into the cytoplasm?

Messenger ribonucleic acid, or mRNA, is like the copy of a recipe. RNA is similar to DNA, but it is only one strand instead of being a double helix. And mRNA is a lot shorter because it only copies one “recipe” instead of the whole “cookbook.” Most cells only need to use a tiny fraction of the genome.

Using mRNA also means that you can make a lot of proteins in a big hurry. Each cell usually only has one copy of any “recipe,” but a whole lot of copies of mRNA can be made from the same stretch of DNA. That would be like taking that one recipe, making a bunch of copies, then giving them to lots of helpers. You’d get a lot more made.

So the mRNA takes the “recipe” out to cytoplasm to ribosomes, which are usually called the workbench of protein synthesis because it’s where the “recipe” is used to put the right amino acids into the right order to make a protein. Sometimes the protein is ready to go and do its job. At other times, it needs some editing first.

Two other types of RNA take part in translating the mRNA message into the string of amino acids. The ribosomes are made of RNA. There are also transfer RNAs that are a sort of decoder of the mRNA.

So, long story short, RNA is necessary for your body to make the proteins that give you structure, let you move (muscles), send signals (hormones), have chemical reactions (enzymes), fight infections (antibodies) and lots of other things that make life possible.

Would it be worse for a mistake to happen when RNA is being made or when DNA is being made so that a cell can divide?