Deoxyribonucleic acid DNA and ribonucleic acid RNA are perhaps the most important molecules in cell biology, responsible for the storage and reading of genetic information that underpins all life.
They are both linear polymers, consisting of sugars, phosphates and bases, but there are some key differences which separate the two 1. These distinctions enable the two molecules to work together and fulfil their essential roles.
Before we delve into the differences, we take a look at these two nucleic acids side-by-side. I Understand. Published: December 18, Last Updated: November 11, DNA encodes all genetic information, and is the blueprint from which all biological life is created. In the long-term, DNA is a storage device, a biological flash drive that allows the blueprint of life to be passed between generations 2. RNA functions as the reader that decodes this flash drive.
This reading process is multi-step and there are specialized RNAs for each of these steps. Below, we look in more detail at the three most important types of RNA.
The nitrogen bases in DNA are the basic units of genetic code, and their correct ordering and pairing is essential to biological function. The four bases that make up this code are adenine A , thymine T , guanine G and cytosine C. Bases pair off together in a double helix structure, these pairs being A and T, and C and G. RNA molecules, by comparison, are much shorter 3. Eukaryotic cells, including all animal and plant cells, house the great majority of their DNA in the nucleus, where it exists in a tightly compressed form, called a chromosome 4.
This squeezed format means the DNA can be easily stored and transferred. In addition to nuclear DNA, some DNA is present in energy-producing mitochondria, small organelles found free-floating in the cytoplasm, the area of the cell outside the nucleus.
The three types of RNA are found in different locations. If it receives the correct signal from the ribosome, it will then hunt down amino acid subunits in the cytoplasm and bring them to the ribosome to be built into proteins 5. Ribosomes are formed in an area of the nucleus called the nucleolus, before being exported to the cytoplasm, where some ribosomes float freely.
Purines are the larger of the two types of bases found in DNA. The 9 atoms that make up the fused rings 5 carbon, 4 nitrogen are numbered All ring atoms lie in the same plane. Cytosine and thymine are pyrimidines. The 6 atoms 4 carbon, 2 nitrogen are numbered Like purines, all pyrimidine ring atoms lie in the same plane. The carbon atoms are numbered 1', 2', 3', 4', and 5' to distinguish from the numbering of the atoms of the purine and pyrmidine rings. The hydroxyl groups on the 5'- and 3'- carbons link to the phosphate groups to form the DNA backbone.
Deoxyribose lacks an hydroxyl group at the 2'-position when compared to ribose, the sugar component of RNA. Nucleosides and Nucleotides A nucleoside is one of the four DNA bases covalently attached to the C1' position of a sugar.
The sugar in deoxynucleosides is 2'-deoxyribose. The sugar in ribonucleosides is ribose. Nucleosides differ from nucleotides in that they lack phosphate groups.
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