Now, the most common type of form that these RNA molecules fold into is known as a stem loop form. And this stem loop form is formed when the ribonucleic acid folds into this double helical structure just like in DNA in which we contain these complementary sequences, these complementary nucleotides that can form base pairs. But in these stem loop structures we also commonly contain these mismatched nucleotides and that destabilizes our structure in that localized region and causes the bulging out of that structure as we'll see in just a moment. So let's suppose we have the following sequence of nucleotides in a given RNA molecule. So this is the beginning, the five end and this is the end, the three end of the ribonucleic acid. Now, if we take this RNA molecule and place it into an aqueous environment found in our cell, it can fold into some type of three dimensional structure.