What substances would not be found in RNA?

Answer 1

To understand what substances do not exist in RNA, it is important to first understand what substances ARE in RNA.

RNA, like DNA, is a polymer. It is made up of many repeating units of molecules, over and over again. RNA is a phosphosugar, meaning that it is primarily made up of molecules of phosphorus and sugars over and over again. In the case of RNA, the sugar in question is the "ribose" sugar. Ribose sugar in RNA is almost indistinguishable from its DNA counter part "deoxyribose" sugar. What separates ribose from deoxyribose, is the presence of an oxygen molecule on the sugar's second carbon, which deoxyribose lacks.

The phosphorus and the ribose alternate repeatedly, over and over to form the backbone of the RNA molecule. In addition to the backbone of RNA, 4 nitrogenous bases are attached to each of the ribose sugars on the backbone. These 4 bases are adenine, cytosine, guanine, and uracil. Particular importance is placed on the presence of uracil in RNA, because uracil also happens to be absent in DNA. Instead, DNA molecules use the base thymine. This too is a distinguishing factor between DNA and RNA.

In knowing this we can make the following important deductions as to what substances are NOT found in RNA:

1. Deoxyribose sugar is not found in RNA (only DNA)

2.Thymine is not found in RNA (only in DNA)

3. Essentially any substance that is not ribose sugar, phosphorus, or any of the RNA bases (A,G,C, and U), is not found traditionally, in RNA.