And the reason it's called a five to five triphosphate linkage is because that linkage is between the fifth carbon on this sugar and the fifth carbon on this ribosugar. So this is the five guanosine triphosphate cap. Now, the question is why exactly should we add this cap to our pre mRNA molecule? What is the function of this cap? Well, basically one important function of this cap is to protect our mRNA from the degradation that could take place during the process of translation, during the process of protein synthesis. And not only that, this addition of the five cap also basically gives our mRNA the ability to leave our nucleus through the nuclear pores and enter the cytoplasm of our cell.