Fig. 6: DNA Replication by Complementary Base Pairing

As the two strands of DNA unwind and separate in both directions, the hydrogen bonding of free DNA nucleotides with those on each parent strand produces new complementary strands. As the new nucleotides line up opposite each parent strand by hydrogen bonding, enzymes called DNA polymerases join the nucleotides by way of phosphodiester bonds. Actually, the nucleotides lining up by complementary base pairing are deoxynucleoside triphosphates, composed of a nitrogenous base, deoxyribose, and three phosphates. As the phosphodiester bond forms between the 5' phosphate group of the new nucleotide and the 3' OH of the last nucleotide in the DNA strand, two of the phosphates are removed providing energy for bonding.


Illustration of DNA Replication by Complementary Base Pairing.jpg by Gary E. Kaiser, Ph.D.
Professor of Microbiology, The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at http://faculty.ccbcmd.edu/~gkaiser/index.html.

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Last updated: August, 2018
Please send comments and inquiries to Dr. Gary Kaiser