Q. Do all molecules of DNA have the same amounts of nitrogenous bases?
Number and sequence of nitrogenous bases in DNA molecule are key elements in variations which are found in chromosomes. Various organisms have various numbers of four bases, and sequence varies in countless ways. In all cases, though, thymine and adenine always stand opposite each other and guanine and cytosine oppose one another. This means that percentage of thymine and adenine would always be the same, as will the percentage of guanine and cytosine.