Nucleic Acids

What are Nucleic Acids?

Nucleic acids are complex molecules that are made of nucleotides. Nucleotides are made up of at least one nitrogenous base(a nitrogen-containing molecule that acts as a base, a sugar with 5 carbon atoms, and a phosphate group(a phosphorous atom bonded with four oxygen atoms).

Nucleic acids are found in all living things. Without nucleic acids, no living organism could survive.

Types of Nucleic Acids

There are two main types of nucleic acids found in living things: DNA(deoxiribonucleic acid) and RNA(ribonucleic acid). DNA is found in the nucleus of cells, and cannot leave the nuclear membrane. RNA is mainly found in the cytoplasm of the cell.


DNA is one of the two main types of nucleic acids. DNA looks like a twisted ladder. The rungs are made up of the nitrogenous bases, and the sides are made up of the sugar and phosphate group. The four nitrogenous bases found in DNA are Adenine, Thymine, Cytosine, and Guanine. Each rung is made up of two nitrogenous bases, which means that two different nitrogenous bases bond together to make up a rung. Adenine always bonds to thymine, and Cytosine always bonds to guanine.

The job of DNA is to hold genetic information in the nitrogenous bases, which are called genes. Genes also hold the genetic information to make proteins. The genes are like the “blueprint” for making proteins. Based on the order of the genes, different proteins are made. No two DNA strands hold the same genetic information.

DNA Image Real

Types of Nucleic Acids

There are two main types of nucleic acids found in all living things.


RNA is the second main type of nucleic acid. RNA is like half of a twisted ladder; it only has one side, and the nucleic acids do not form in pairs. The four nucleic acids in RNA are Adenine, Uracil(instead of Thymine), Cytosine, and Guanine. RNA’s job is to help DNA make proteins. There are three types of RNA: Ribosomal RNA, Transport RNA, and Messenger RNA. Each type of RNA serves a different purpose in protein synthesis(the making of proteins; see my post on protein synthesis to learn more).

RNA Image Real


Each nucleic acid contains a sugar with five carbon atoms in its strands. In RNA, the sugar is called ribose(C5 H10 O5).  In DNA, the sugar is a modified version of ribose called deoxiribose(C5 H10 O4).