Now, what exactly is RNA? RNA stands for ribonucleic acid and RNA is very similar to DNA in that it is also a polymer that consists of individual units known as nucleotides. And just like in DNA our nucleotides in RNA also consist of three important parts. We have a sugar, we have a phosphate group and we also have a nitrogenous base. Now let's begin by differentiating the type of sugar that exists in DNA and RNA molecules. So recall in DNA molecules the sugar that is involved is the deoxyribose sugar and the sugar looks something like this.