PSI. Pounds per square inch: a unit for measuring pressure. One PSI equals the pressure resulting from a force of one pound force acting over an area of one square inch. See pound.
  The four bases that make up RNA are:   * Adenine (A)  * Cytosine (C)  * Guanine (G)  * Uracil (U).denine and guanine are complementary, as are thymine and cytosine. RNA is practically the same, â¦ except that thymine is replaced with uracil (U) - meaning that when RNA replicates DNA, any thymine needed is replaced with uracil. Uracil is still compatible with cytosine, though.
Sugar Backbones. DNA and RNA are made up of subunits called nucleotides. All nucleotides have a sugar backbone, a phosphate group, and a nitrogenous base. Both DNA and RNA have sugar âbackbonesâ that are made up of five carbon molecules. However, they are different sugars that make them up. DNA is made up of deoxyribose and RNA is made up of ribose. Those sound pretty similar and their structures are very similar.