Nucleotide Polymers (Campbell Biology)
The linkage of nucleotides into a polynucleotide involves a dehydration reaction. In the polynucleotide, adjacent nucleotides are joined by a phosphodiester linkage, which consists of a phosphate group that links the sugars of two nucleotides. This bonding results in a repeating pattern of sugar-phosphate units called the sugar-phosphate backbone. The two free ends of the polymer are distinctly different from each other. One end has a phosphate attached to a 5′ carbon, and the other end has a hydroxyl group on a 3′ carbon; we refer to these as the 5′ end and the 3′ end, respectively. We can say that a polynucleotide has a built-in directionality along its sugar-phosphate backbone, from 5′ to 3′, somewhat like a one-way street. The bases are attached all along the sugar-phosphate backbone.
The sequence of bases along a DNA (or mRNA) polymer is unique for each gene and provides very specific information to the cell. Because genes are hundreds to thousands of nucleotides long, the number of possible base sequences is effectively limitless. The information carried by the gene is encoded in its specific sequence of the four DNA bases. For example, the sequence 5′-AGGTAACTT-3′ means one thing, whereas the sequence 5′-CGCTTTAAC-3′ has a different meaning. The linear order of bases in a gene specifies the amino acid sequence—the primary structure—of a protein, which in turn specifies that protein’s 3-D structure, thus enabling its function in the cell.
Urry, Lisa A.. Campbell Biology. Pearson Education. Kindle Edition. https://www.pearson.com/us/higher-education/series/Campbell-Biology-Series/2244849.html
Date Published: May 18, 2011 Publisher: Public Library of Science Author(s): Manfred G. Grabherr, Jens Pontiller, Evan Mauceli, Wolfgang Ernst, Martina Baumann, Tara Biagi, Ross Swofford, Pamela Russell, Michael C. Zody, Federica Di Palma, Kerstin Lindblad-Toh, Reingard M. Grabherr, Arkady B. Khodursky. http://doi.org/10.1371/journal.pone.0020136 Abstract: The choice of promoter is a critical step in optimizing the efficiency … Continue reading
Date Published: April 22, 2011 Publisher: Public Library of Science Author(s): Joshua Ballanco, Marc L. Mansfield, Cathal Seoighe. http://doi.org/10.1371/journal.pone.0018881 Abstract: In all known living organisms, every enzyme that synthesizes nucleic acid polymers does so by adding nucleotide 5′-triphosphates to the 3′-hydroxyl group of the growing chain. This results in the well known directionality of all DNA … Continue reading
Date Published: April 24, 2009 Publisher: Public Library of Science Author(s): Jia Yao, Sandra M. Bajjalieh, Patrick Callaerts. http://doi.org/10.1371/journal.pone.0005315 Abstract: Synaptic Vesicle Protein 2 (SV2) and SV2-related protein (SVOP) are transporter-like proteins that localize to neurotransmitter-containing vesicles. Both proteins share structural similarity with the major facilitator (MF) family of small molecule transporters. We recently reported that … Continue reading
Date Published: September 30, 2010 Publisher: Public Library of Science Author(s): Justin Gerke, Kim Lorenz, Shelina Ramnarine, Barak Cohen, Trudy F. C. Mackay Abstract: Interactions among genes and the environment are a common source of phenotypic variation. To characterize the interplay between genetics and the environment at single nucleotide resolution, we quantified the genetic and … Continue reading
Date Published: May 1, 2017 Publisher: Public Library of Science Author(s): Thaddeus R. Cybulski, Edward S. Boyden, George M. Church, Keith E. J. Tyo, Konrad P. Kording, Sergei L. Kosakovsky Pond Abstract: Using a DNA polymerase to record intracellular calcium levels has been proposed as a novel neural recording technique, promising massive-scale, single-cell resolution monitoring … Continue reading