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. Most often, this information is used to manufacture proteins. Transcription begins when an enzyme called RNA polymerase attaches to the DNA template strand and begins assembling a new chain of nucleotides to produce a complementary RNA strand.
There are multiple types of types of RNA. Generally speaking, polymerases are large enzymes that work together with a number of other specialized cell proteins.
These cell proteins, called transcription factors , help determine which DNA sequences should be transcribed and precisely when the transcription process should occur.
This means that during elongation, the presence of adenine in the DNA template strand tells RNA polymerase to attach a uracil in the corresponding area of the growing RNA strand Figure 4.
When this base-pairing happens, RNA uses uracil yellow instead of thymine to pair with adenine green in the DNA template below. A second major difference between the two substances is that RNA is made in a single-stranded, nonhelical form. Remember, DNA is almost always in a double-stranded helical form. Furthermore, RNA contains ribose sugar molecules, which are slightly different than the deoxyribosemolecules found in DNA. As its name suggests, ribose has more oxygen atoms than deoxyribose. This page appears in the following eBook.
Aa Aa Aa. How does transcription proceed? The first step in transcription is initiation. During this step, RNA polymerase and its associated transcription factors bind to the DNA strand at a specific area that facilitates transcription Figure 1. Strand elongation. Once RNA polymerase and its related transcription factors are in place, the single-stranded DNA is exposed and ready for transcription. At this point, RNA polymerase begins moving down the DNA template strand in the 3' to 5' direction, and as it does so, it strings together complementary nucleotides.
By virtue of complementary base- pairing, this action creates a new strand of mRNA that is organized in the 5' to 3' direction. This process is called elongation. As the mRNA elongates, it peels away from the template as it grows Figure 5.
This is a comparison of the differences between DNA versus RNA, including a quick summary and a detailed table of the differences. This table summarizes the key points:.
Also, RNA is found in prokaryotes , which are believed to precede eukaryotes. RNA on its own can act as a catalyst for certain chemical reactions. The most likely answer for this is that having a double-stranded molecule helps protect the genetic code from damage. If one strand is broken, the other strand can serve as a template for repair. Proteins surrounding DNA also confer additional protection against enzymatic attack.
While the most common form of DNA is a double helix. It is similar to DNA, except thymine is replaced by uracil. This type of RNA is found in some viruses. When these viruses infect eukaryotic cells, the dsRNA can interfere with normal RNA function and stimulate an interferon response. Alberts, Bruce, et al.
Archer, Stuart A. Tawfik, Dan S. Lasda, Erika, and Roy Parker. Proteins protect DNA inside the nucleus. In addition, the molecule has several repair mechanisms and is stable in alkaline conditions. In addition, its single-strand structure makes it more vulnerable to enzyme attacks. The link between UV radiation and skin cancer is caused in part by this vulnerability. For starters, we can easily note that they are both types of nucleic acids, chainlike molecules composed of nearly identical units called nucleotides.
Individual nucleotides are called monomers, while the linked together molecule is called a polymer. DNA and RNA are both fantastic molecules with specific characteristics that make them suitable for their job. The intricate design of DNA makes it unique, and it has been the topic of interest not only in research, but also forensics , paternity tests, and commercial genetic testing for traits and diseases.
At Nebula Genomics, we know the importance of knowing what is written in your DNA to your health and well-being. Whether you want to know about your ancestry , your close family, or would like to check if you are susceptible to developing a certain disease, or maybe want to create a personalized diet, our 30x Whole Genome Sequencing guarantees complete information of your genome.
So go ahead and order your DNA test kit today! Looking for more educational material? You may be interested in our other articles such as this one on the history of the DNA model. CC- Attribution-Share Alike 3. Ribose vs deoxyribose sugar. CC- Attribution-Share Alike 4. DNA nucleotide.
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