When the total pressure is considered, as in chemical analysis and in thermodynamics it is often referred to as psia or absolute pressure of the substance or of the fluid which would then include the atmospheric pressure. It is important to include the subscript g or a to define which pressure is being noted. Psi can also be the difference between two pressures, be they gage or absolute. Psi is also used in materials engineering referring to the unit stress caused when a load is imposed on a structure or on a part.
Adenine is one of the two purine nucleobases (the other being guanine) used in forming nucleotides of the nucleic acids. In DNA, adenine binds to thymine via two hydrogen bonds to assist in stabilizing the nucleic acid structures. In RNA, which is used for protein synthesis, adenine binds to uracil.
DNA is made up of chains of nucleotides, molecules made up from purine, pentose sugar, and a phosphate group, put onto a sugar and phosphate backbone and wrapped around each other; this is called a double helix. There are four bases in DNA; guanine, cytosine, adenine, and thymine.here are four bases that make up RNA just as DNA has. RNA's four bases consist of adenine, cytosine, guanine, and uracil. RNA is also what a mutagen looks for. If a mutagen takes over RNA it is able to change the DNA and make the cell do what the mutagen wants it to do rather then what it is supposed to do.