137 Key Terms

electrophoresis
technique used to separate DNA fragments according to size
helicase
during replication, this enzyme helps to open up the DNA helix by breaking the hydrogen bonds
induced mutation
mutation that results from exposure to chemicals or environmental agents
lagging strand
during replication, the strand that is replicated in short fragments and away from the replication fork
leading strand
strand that is synthesized continuously in the 5′-3′ direction, which is synthesized in the direction of the replication fork
ligase
enzyme that catalyzes the formation of a phosphodiester linkage between the 3′ OH and 5′ phosphate ends of the DNA
mismatch repair
type of repair mechanism in which mismatched bases are removed after replication
mutation
variation in the nucleotide sequence of a genome
nucleotide excision repair
type of DNA repair mechanism in which the wrong base, along with a few nucleotides upstream or downstream, are removed
Okazaki fragment
DNA fragment that is synthesized in short stretches on the lagging strand
point mutation
mutation that affects a single base
primase
enzyme that synthesizes the RNA primer; the primer is needed for DNA pol to start synthesis of a new DNA strand
primer
short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides
proofreading
function of DNA pol in which it reads the newly added base before adding the next one
replication fork
Y-shaped structure formed during initiation of replication
silent mutation
mutation that is not expressed
single-strand binding protein
during replication, protein that binds to the single-stranded DNA; this helps in keeping the two strands of DNA apart so that they may serve as templates
sliding clamp
ring-shaped protein that holds the DNA pol on the DNA strand
spontaneous mutation
mutation that takes place in the cells as a result of chemical reactions taking place naturally without exposure to any external agent
telomerase
enzyme that contains a catalytic part and an inbuilt RNA template; it functions to maintain telomeres at chromosome ends
telomere
DNA at the end of linear chromosomes
topoisomerase
enzyme that prevents overwinding of DNA when DNA replication is taking place
transformation
process in which external DNA is taken up by a cell
transition substitution
when a purine is replaced with a purine or a pyrimidine is replaced with another pyrimidine
transversion substitution
when a purine is replaced by a pyrimidine or a pyrimidine is replaced by a purine

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Biology 2e Part I, 2nd edition Copyright © 2022 by LOUIS: The Louisiana Library Network is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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