front 1 DNA Replication | back 1 The process by which a DNA molecule is copied; also called DNA synthesis |
front 2 Transformation | back 2 A change in genotype and phenotype due to the assimilation of external DNA by a cell |
front 3 Bacteriophage | back 3 A virus that infects bacteria |
front 4 Double Helix | back 4 The form of native DNA, referring to it's two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape |
front 5 Antiparallel | back 5 Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix. They run opposite 5' --> 3' |
front 6 Chromatin | back 6 The complex of DNA and proteins that make up eukaryotic chromosomes. When the cell is no dividing, this exists in a dispersed form |
front 7 DNA ligase | back 7 A linking enzyme that is essential for the DNA replication; catalyzes the covalent bonding of the 3' end of one DNA fragment to the 5' end of another fragment |
front 8 DNA polymerase | back 8 An enzyme that catalyzes the elongation of new DNA by the addition of nucleotides to the 3' end of an existing chain |
front 9 Euchromatin | back 9 The less condensed form of eukaryotic chromatin that is available for transcription |
front 10 Histones | back 10 A small protein with a high proportion of positively charged amino acids that binds to the negatively charged DNA and plays a key role in chromatin structure |
front 11 Heterochromatin | back 11 Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed |
front 12 Helicases | back 12 An enzyme that untwists the double helix of DNA at replication forks, separating the two strands and making them available as template strands |
front 13 Lagging Strand | back 13 A discontinuously synthesized strand that elongates by means of Okazaki fragments, each synthesized in a 5' --> 3' direction away from the replication fork |
front 14 Leading Strand | back 14 The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5' --> 3' direction |
front 15 Mismatch repair | back 15 The cellular process that uses specific enzymes to remove and replace incorrectly paired nucleotides |
front 16 Nuclease | back 16 An enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides |
front 17 Nucleosome | back 17 The basic, beadlike unit of DNA packing in eukaryotes, consisting of a segment of DNA wound around a protein core composed of two copies of each of the four types of histone |
front 18 Nucleotide excision repair | back 18 A repair system that removes and then correctly replaces a damaged segment of DNA using the undamaged strand as a guide |
front 19 Okazaki fragments | back 19 A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication. These segments are joined together to make up the lagging strand of newly synthesized DNA |
front 20 Origins of Replication | back 20 Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides |
front 21 Primer | back 21 A short stretch of RNA with a free 3' end, bound by complementary base pairing to the template strand and elongated with DNA nucleotides during DNA replication |
front 22 Primase | back 22 An enzyme that joins RNA nucleotides to make a primer during DNA replication, using the parental DNA strand as a template |
front 23 Replication fork | back 23 A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are being synthesized |
front 24 Single Stranded Binding Proteins | back 24 A protein that binds to the unpaired DNA strands during DNA replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary strands of DNA |
front 25 Semiconservative model | back 25 A type of DNA replication in which the replicated double helix consists of one old strand, derived from the parental molecule, and one newly made strand |
front 26 Telomeres | back 26 The tandemly repetitive DNA at the end of a eukaryotic chromosomes DNA molecule. They protect the organisms genes from being eroded during successive rounds of replication. |
front 27 Topoisomerase | back 27 A protein that breaks, swivels and rejoins DNA strands. During DNA replication, it helps to relieve strain in the double helix ahead of the replication fork |
front 28 Virus | back 28 An infectious particle incapable of replicating outside of a cell, consisting of an RNA or DNA genome surrounded by a protein coat and, for some, a membranous envelope |