DNA vs. RNA – 5 Key Differences and Comparison
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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 two1. These distinctions enable the two molecules to work together and fulfil their essential roles. Here, we look at 5 key differences between DNA and RNA. Before we delve into the differences, we take a look at these two nucleic acids side-by-side.
- Triplex DNA
Figure 1: A comparison of the helix and base structure of RNA and DNA. Credit: Technology Networks.
DNA vs. RNA – A comparison chart
|Full Name||Deoxyribonucleic Acid||Ribonucleic Acid|
DNA replicates and stores genetic information. It is a blueprint for all genetic information contained within an organism.
RNA converts the genetic information contained within DNA to a format used to build proteins, and then moves it to ribosomal protein factories.
DNA consists of two strands, arranged in a double helix. These strands are made up of subunits called nucleotides. Each nucleotide contains a phosphate, a 5-carbon sugar molecule and a nitrogenous base.
RNA only has one strand, but like DNA, is made up of nucleotides. RNA strands are shorter than DNA strands. RNA sometimes forms a secondary double helix structure, but only intermittently.
DNA is a much longer polymer than RNA. A chromosome, for example, is a single, long DNA molecule, which would be several centimetres in length when unravelled.
RNA molecules are variable in length, but much shorter than long DNA polymers. A large RNA molecule might only be a few thousand base pairs long.
The sugar in DNA is deoxyribose, which contains one less hydroxyl group than RNA’s ribose.
RNA contains ribose sugar molecules, without the hydroxyl modifications of deoxyribose.
The bases in DNA are Adenine (‘A’), Thymine (‘T’), Guanine (‘G’) and Cytosine (‘C’).
RNA shares Adenine (‘A’), Guanine (‘G’) and Cytosine (‘C’) with DNA, but contains Uracil (‘U’) rather than Thymine.
Adenine and Thymine pair (A-T)
Cytosine and Guanine pair (C-G)
Adenine and Uracil pair (A-U)
Cytosine and Guanine pair (C-G)
DNA is found in the nucleus, with a small amount of DNA also present in mitochondria.
RNA forms in the nucleolus, and then moves to specialised regions of the cytoplasm depending on the type of RNA formed.
|Reactivity||Due to its deoxyribose sugar, which contains one less oxygen-containing hydroxyl group, DNA is a more stable molecule than RNA, which is useful for a molecule which has the task of keeping genetic information safe.||RNA, containing a ribose sugar, is more reactive than DNA and is not stable in alkaline conditions. RNA’s larger helical grooves mean it is more easily subject to attack by enzymes.|
|Ultraviolet (UV) Sensitivity||DNA is vulnerable to damage by ultraviolet light.||RNA is more resistant to damage from UV light than DNA.|
What are the key differences between DNA and RNA?
We can identify five key categories where DNA and RNA differ: