Course: SAT 170 Introductory Biotechnology

Unit 3 Reading and Multimedia Assignment

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Page 9 of 13
DNA Synthesis
DNA replication is carried out by the enzyme DNA polymerase, which requires a short fragment of DNA or RNA primer to begin DNA synthesis.
DNA polymerases are a family of enzymes that carry out all forms of DNA replication. However, a DNA polymerase can only extend an existing DNA strand paired with a template strand; it cannot begin the synthesis of a new strand. To begin synthesis, a short fragment of DNA or RNA, called a primer, is created and paired with the template DNA strand.

DNA polymerase assembles new DNA strands from deoxynucleoside triphosphates, free bases plus deoyribose sugar and three phosphate groups. When a nucleotide is being added to a growing DNA strand, a pyrophosphate (2 P) is removed and then hydrolyzed to two inorganic phoshate molecules. The energy produced creates a phosphodiester bond that attaches the remaining phosphate to the growing DNA chain.