ch. 14 Flashcards
what is electrophoresis?
the technique used to separate DNA fragments according to size
what is helicase?
an enzyme that helps to open up the DNA helix by breaking the hydrogen bonds
what is induced mutation?
mutation that results from exposure to chemicals or environmental agents
what is a lagging strand?
the strand that is replicated in short fragments and away from the replication fork during replication
what is a leading strand?
the strand that is synthesized continuously in the 5’-3’ direction/the direction of the replication fork during replication
what is ligase?
an enzyme that catalyzes the formation of a phosphodiester linkage between the 3’ OH and 5’ phosphate ends of the DNA
what is mismatch repair?
a type of repair mechanism in which mismatched bases are removed after replication
what is a mutation?
a variation in the nucleotide sequence of a genome
what is nucleotide excision repair?
a type of DNA repair mechanism in which the wrong base, along with a few nucleotides upstream or downstream, are removed
what is an Okazaki fragment?
DNA fragment that is synthesized in short stretches on the lagging strand
what is point mutation?
mutation that affects a single base?
what is primase?
an enzyme that synthesizes the RNA primer; the primer is needed for DNA pol to start synthesis of a new DNA strand
what is a primer?
a short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides
what is proofreading?
the function of DNA pol in which it reads the newly added base before adding the next one
what is the replication fork?
a Y-shaped structure formed during initiation of replication
what is silent mutation?
mutation that is not expressed
what is a single-strand binding protein?
the protein that binds to the single-stranded DNA during replication (helps keep the two strands apart so that they can act as templates)
what is a sliding clamp?
a ring-shaped protein that holds the DNA pol on the DNA strand
what is spontaneous mutation?
mutation that takes place in the cells as a result of chemical reactions taking place naturally without exposure to any external agent
what is telomerase?
an enzyme that contains a catalytic part and an inbuilt RNA template; functions to maintain telomeres at chromosome ends)
what is a telomere?
the DNA at the end of linear chromosomes
what is topoisomerase?
an enzyme that causes underwinding or overwinding of DNA when replication is taking place
what is transformation?
the process in which external DNA is taken up by a cell
what is transition substitution?
when a purine is replaced with a purine or a pyrimidine is replaced with another pyrimidine
what is transversion substitutions?
when a purine is replaced with a pyrimidine or a pyrimidine is replaced by a purine
