Page 115 - Academic Press Encyclopedia of Physical Science and Technology 3rd BioChemistry

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Nucleic Acid Synthesis

Sankar Mitra
Tapas K. Hazra
Tadahide Izumi
University of Texas Medical Branch, Galveston

I. Structure and Function of Nucleic Acids
II. Nucleic Acid Syntheses
III. DNA Replication and Its Regulation
IV. Maintenance of Genome Integrity
V. DNA Manipulations and Their Applications
VI. Transcriptional Processes
VII. Chemical Synthesis of Nucleic Acids
(Oligonucleotides)

GLOSSARY Cis element Short, specific DNA sequences, usually in
the promoter, that bind cognate trans-acting factors.
Cellcycle Stagesinthelifecycleofreplicatingeukaryotic Deoxyribonucleotides Monomeric units of DNA, inclu-
cells. After cell division (mitosis), a cell goes through ding deoxyadenylic (dAMP), deoxyguanylic (dGMP),
the resting G1/Go phase prior to DNA replication in the deoxycytidylic (dCMP), and deoxythymidylic (dTMP)
S phase. Completion of duplication of cellular materi- acids.
als in the G2 phase occurs prior to mitosis (M phase). DNA Deoxyribonucleic acid: linear copolymers of mo-
Chromatin Cellular genome as nucleoprotein which nomeric deoxyribonucleotides normally present as a
contains DNA, histones, and a variety of nonhistone two-stranded intertwined helix; the deoxyribose sugar
chromosomal proteins. moiety lacks
Chromatin remodeling Alteration in the structure of DNA helicase An enzyme which unwinds the double he-
segment of chromatin which is brought about by hi- lical DNA using energy provided by ATP hydrolysis.
stone acetylation/deacetylation and/or mediated by in- DNA ligase The enzyme which catalyzes joining of the 5

teraction with large protein complexes as a prerequisite and 3 termini of two single-stranded DNA fragments
for modulation of transcription activity. in a double-stranded DNA by forming a phosphodiester
Chromosomes Discrete and microscopically visible seg- bond.
ments of the eukaryotic genome complexed with pro- DNA repair Enzymatic process that maintains sequence
teins and capped by telomeres; each normally contains integrity by removing both endogenously and exoge-
thousands of genes. nously induced DNA damage. Such lesions could be

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