Search results
Results from the WOW.Com Content Network
In DNA, the uracil nucleobase is replaced by thymine (T). Uracil is a demethylated form of thymine. Uracil is a common and naturally occurring pyrimidine derivative. [2] . The name "uracil" was coined in 1885 by the German chemist Robert Behrend, who was attempting to synthesize derivatives of uric acid. [3] .
It is believed that thymine replaced uracil (the RNA base) in DNA because of the deleterious effects of slow spontaneous deamination of cytosine to uracil: by employing thymine instead of uracil, any uracil in DNA would clearly be aberrant, allowing a specific mechanism of repair (involving uracil DNA glycosylase) to evolve with impunity. As ...
This offers a rough explanation of why thymine is more protected then uracil. However, the real question is: Why does thymine replace uracil in DNA? The important thing to notice is that while uracil exists as both uridine (U) and deoxy-uridine (dU), thymine only exists as deoxy-thymidine (dT).
Uracil (U) is one of the four nucleotide bases in RNA, with the other three being adenine (A), cytosine (C) and guanine (G). In RNA, uracil pairs with adenine. In a DNA molecule, the nucleotide thymine (T) is used in place of uracil.
To get around this, our bodies have a protein (called Uracil-DNA glycosylase) that removes the U's so that they can be replaced with C's. This solves the problem of C's spontaneously turning into U's. Because U's are foreign to DNA, our cells know to replace them with C's.