Chapter 6 Flashcards
DNA ligase
Enzyme that seals nicks that arise in the backbone of a DNA
molecule; in the laboratory, can be used to join together two
DNA fragments.
DNA repair
Collective term for the enzymatic processes that correct
damage to DNA.
DNA polymerase
Enzyme that catalyzes the synthesis of a DNA molecule from
a DNA template using deoxyribonucleoside triphosphate
precursors
DNA replication
The process by which a copy of a DNA molecule is made.
lagging strand
At a replication fork, the DNA strand that is made
discontinuously in short fragments that are later joined
together to form one continuous new strand.
leading strand
At a replication fork, the DNA strand that is made by
continuous synthesis in the 5′-to-3′ direction.
mutation
A randomly produced, permanent change in the nucleotide
sequence of DNA.
Okazaki fragment
Short length of DNA, including an RNA primer, produced on
the lagging strand during DNA replication. Following primer
removal, adjacent fragments are rapidly joined together by
DNA ligase to form a continuous DNA strand.
primase
An RNA polymerase that uses DNA as a template to produce
an RNA fragment that serves as a primer for DNA synthesis.
proofreading
The process by which DNA polymerase corrects its own
errors as it moves along DNA.
replication fork
Y-shaped junction at the site where DNA is being replicated.
replication origin
Nucleotide sequence at which DNA replication is initiated.
telomerase
Enzyme that elongates telomeres, synthesizing the
repetitive nucleotide sequences found at the ends of
eukaryotic chromosomes.
telomere
Repetitive nucleotide sequence that caps the ends of
linear chromosomes. Counteracts the tendency of the
chromosome otherwise to shorten with each round of
replication.
template
A molecular structure that serves as a pattern for the
production of other molecules. For example, one strand
of DNA directs the synthesis of the complementary DNA
strand.
