RNA Structure

The structure shown here (that we just looked at on th Linking Nucleotides page) is essentially the structure of ribonucleic acid because the sugar shown here is ribose. The bases used are not specified, but if they were, they would be adenine, guanine, cytosine, and uracil, because those are the bases that can be incorporated into ribonucleic acid.

Structure of RNA. [69027.jpg]

You can see a more complete representation of the structure of RNA in your textbook. Whichever diagram of RNA you use, note that RNA includes adenine, cytosine, guanine and uracil. Each of those bases is attached to a ribose sugar molecule (note that there's an OH on the second carbon). The ribose molecules are bonded to one another by a phosphate linkage attaching the third carbon of one ribose to the fifth carbon of the next ribose. This nucleic acid is said to have a backbone made of sugar molecules and phosphate molecules and that's what forms the chain of the polynucleotide. The bases are then essentially attached to the side of that chain.

Another source of good diagrams and much additional information about the structure of RNA (and also DNA) is the Biochemistry in 3D web site maintained by Worth Publishers as a supplement to an excellent Biochemistry text by Lehninger. You can find the site at http://www.worthpublishers.com/lehninger3d/index.html. When you get there, check out the tutorial on Nucleotides (Building Blocks of Nucleic Acids). You might want to look at the DNA Structure page here before checking out that Lehninger site.

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