| Term | Definition |
|---|
| transformation | a change in genotype and phenotype due to assimilation of external DNA by a cell |
| bacteriophages | viruses that infect bacteria |
| double helix | the presence of 2 strands of DNA |
| semiconservative model | type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand |
| dispersive model | all four strands of DNA following replication have a mixture of old and new DNA |
| origins of replication | the replication of a DNA molecule begins at special sites called _________ ___ _______ |
| replication fork | at each end of a replication bubble is a ________ ________, a Y-shaped region where the new strands of DNA are elongating |
| DNA polymerases | elongation of new DNA at a replication fork is catalyzed by enzymes called ______ _________ |
| antiparallel | the two strands of DNA in a double helix are ________, meaning they are oriented in opposite directions to each other |
| leading strand | the new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' --> 3' direction |
| lagging strand | the discontinuously synthesized DNA strand that elongates in a direction away from the replication fork |
| okazaki fragments | as the bubble grows, another segment of the lagging strand can be made in a similar way by ______ ________ |
| DNA ligase | an enzyme that eventually joins the sugar-phosphate backbones of the Okazaki fragments |
| primer | the initial nucleotide chain is a short one called a _________. These may consist of either DNA or RNA, and in initiating the replication of cellular DNA, this is a short stretch of DNA with an available 3' end |
| primase | an enzyme called _____ can start an RNA chain from scratch. it joins RNA nucleotides together one at a time, making a primer complementary to the template strand at the location where initiation of the new DNA strand will occur |
| helicase | an enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands |
| topoisomerase | a protein that junctions in DNA replication, helping to receive strain in the double helix ahead of the replication fork |
| single-strand binding protein | after helicase separates the 2 parental strands, molecules of ______-_______ _______ __________ then bind to the unpaired DNA strands, stabilizing them until they serve as templates for the synthesis of new complementary strands |
| mismatch repair | in ________ ________, cells use special enzymes to fix incorrectly paired nucleotides |
| nuclease | usually, a segment of the strand containing the damage is cut out by a DNA-cutting enzyme (a ________) and the resulting gap is filled with nucleotides properly paired with the nucleotides in the undamaged strand |
| nucleotide excision repair | the process of removing and then correctly replacing a damaged segment of DNA using the damaged strand as a guide |
| telomeres | eukaryotic chromosomal DNA molecules have nucleotide sequences called _______ at their ends |
Combine with other sets
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