What is the difference between DNA and RNA? DNA and RNA are both types of nucleic acids, which are molecules that contain sets of instructions for cells to make genetic information and proteins. However, there are significant differences between the two of them. This guide will compare and contrast DNA and RNA in terms of structure, function, location, and more. After we give overviews of both DNA and RNA, there's a chart that allows you to easily see each key difference between DNA and RNA.
What Is DNA?
DNA stands for deoxyribonucleic acid. It's a macromolecule that is one of the most important components of our cells. Without DNA, cell functions like growth and reproduction wouldn't be possible.
DNA Structure
DNA is made up of four chemical bases: Adenine (A), Guanine (G), Cytosine (C), and Thymine (T). Human DNA consists of roughly 3 billion bases. Over 99% of those combinations are identical in humans. In DNA, A always pairs with G, and C always pairs with T. These base pairs are bonded with hydrogen bonds and are then connected to a sugar-phosphate "backbone." Put all together, they create the well-known "double helix" shape that DNA has.
DNA's Function
DNA stores and transfers genetic information. Think of it as your body's blueprint, containing all the instructions for development, growth, functioning, and reproduction. The massive amounts of information that DNA contains are converted into "messages" that allow cells to carry out these necessary and diverse tasks.
DNA's Location in Cells
Most DNA is located in the cell's nucleus. The nucleus is the control center of the cell, and it determines how the cell will function. Small amounts of DNA can also be found in the mitochondria, another organelle in cells whose function is to convert energy from food into a form that cells can use.
DNA Replication
DNA is self-replicating, which means that each strand of DNA acts as a template for the creation of new strands. RNA primer is used to initiate the replication process.
During replication, first the double helix "unzips," exposing the two DNA strands. (This is done by an enzyme called helicase, which breaks the hydrogen bonds between the base pairs.) After the DNA is unzipped, two strands are created, the "leading strand" and the "lagging strand." The leading strand is replicated as a continuous piece, while the lagging strand is made in smaller pieces.
DNA Reactivity
As you might expect for such a critical part of the human body, DNA has multiple protections in place to make it less vulnerable to changes, either through mutation or attack. DNA is protected by proteins, contains multiple repair mechanisms, and is stable under alkaline conditions. However, DNA is more vulnerable to damage from ultraviolet light than RNA is.
What Is RNA?
Like DNA, RNA is also a macromolecule made up of nucleotides. RNA plays multiple roles, including controlling gene expression, communicating cellular signals, and catalyzing biological reactions. So how is RNA different from DNA? The sections below follow the same order as the DNA sections, so you can easily compare DNA vs RNA structure, function, and more.
RNA Structure
While DNA is double-stranded, forming a double helix shape, RNA is single-stranded, and its chains are significantly shorter than DNA chains (a few thousand base pairs at most, compared to millions of DNA base pairs).
RNA’s single-strand structure allows it to form complex three-dimensional shapes. The shape it forms determines whether RNA acts as mRNA, tRNA, or rRNA.
Like DNA, RNA is made of a sugar-phosphate background with nitrogenous bases bonded by hydrogen bonds. However, while the sugar in DNA is deoxyribose, the sugar in RNA is ribose. Unlike deoxyribose, ribose has a hydroxyl group (-OH) attached to the second carbon of the sugar ring, as opposed to a hydrogen (-H).
Also like DNA, cytosine and guanine bond with each other in RNA. However, unlike DNA, RNA doesn’t contain thymine. Instead, uracil bonds with adenine. Two hydrogen bonds form between adenine and uracil, and three hydrogen bonds form between cytosine and guanine.
RNA's Function
If you think of DNA as the blueprint for cell processes, then RNA is the worker who puts the blueprint instructions into action. RNA converts the information that DNA contains into proteins, which can then carry out different processes. There are three main types of RNA, each with a different role:
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Messenger RNA (mRNA): Carries codes from DNA to sites of protein synthesis on ribosomes in cell cytoplasm.
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Transfer RNA: (tRNA): Carries amino acids to ribosomes.
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Ribosomal RNA: (rRNA): Combines with proteins to form ribosomes and translates information from mRNA and tRNA.
RNA's Location in Cells
RNA forms in the nucleolus of cells. The nucleolus is a structure within the nucleus of the cell whose purpose is to construct ribosomes (which are made of RNA and protein). After the RNA has been created, it moves to certain regions of the cell's cytoplasm depending on the type of RNA it is.
RNA Replication
Unlike DNA, RNA is not self-replicating. Instead, RNA is synthesized from DNA through the process of transcription. During transcription, a segment of DNA is copied to create an RNA molecule. RNA polymerase is the main enzyme, and it uses the DNA strands to make a complementary RNA strand.
RNA Reactivity
The hydroxyl (-OH) bonds in RNA make it more reactive than DNA. RNA is frequently broken down and reused compared to the more long-lasting DNA. RNA is also unstable at alkaline conditions, while DNA is stable. However, compared to DNA, RNA is more resistant to UV damage.
DNA vs RNA: The Key Differences
What is the difference between DNA and RNA, or the ribose vs deoxyribose nucleic acids? This DNA vs RNA chart allows you to easily see each of the important ways that DNA and RNA differ from each other.
| DNA | RNA | |
| Full Name | Deoxyribonucleic acid | Ribonucleic acid |
| Function | Replicates and stores genetic information | Carry out instructions encoded in DNA |
| Structure | Two strands | One strand |
| Sugar | Deoxyribose (which has one less hydroxyl group than ribose) | Ribose |
| Base Pairs | Adenine + Thymine Guanine + Cytosine | Adenine + Uracil Guanine + Cytosine |
| Pairs Bonded By | Hydrogen bonds | Hydrogen bonds |
| Location in Cells | Mostly nucleus, some in mitochondria | Form in nucleolus, then move to cytoplasm |
| Length | Several million base pairs | Several thousand base pairs |
| Replication | Self-replicating | Synthesized by transcription |
| Reactivity | Fairly stable | More reactive |
What's Next?
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If you want to better understand what DNA is, you need to know about nucleotides. In our guide to nucleotides, we explain what they are and how they make up DNA.
What are the most important science classes to take in high school? Check out our guide to learn all the high school classes you should be taking.
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Christine graduated from Michigan State University with degrees in Environmental Biology and Geography and received her Master's from Duke University. In high school she scored in the 99th percentile on the SAT and was named a National Merit Finalist. She has taught English and biology in several countries.
Holly R.