e1-3 Flashcards
Blue Word
Definition
Replication fork
A Y-shaped structure where DNA is actively being replicated.
DNA helicase
An enzyme that unwinds the DNA double helix by breaking hydrogen bonds.
single-strand DNA binding protein
Proteins that stabilize single-stranded DNA and prevent it from reannealing.
DNA polymerase
An enzyme that synthesizes new DNA strands by adding nucleotides to a primer.
Okazaki fragments
Short DNA fragments synthesized on the lagging strand during replication.
lagging strand
The DNA strand that is synthesized discontinuously in the 5’ to 3’ direction.
leading strand
The DNA strand that is synthesized continuously in the 5’ to 3’ direction.
Primase
An enzyme that synthesizes short RNA primers for DNA replication.
DNA ligase
An enzyme that seals nicks between Okazaki fragments by forming phosphodiester bonds.
telomerase
An enzyme that extends the ends of chromosomes to prevent shortening.
telomeres
Repetitive DNA sequences at the ends of chromosomes that protect them from degradation.
reverse transcription
The process of synthesizing DNA from an RNA template.
3’ hydroxyl
The free hydroxyl (-OH) group at the 3’ end of a DNA or RNA strand.
proofreading
The ability of DNA polymerase to correct errors during replication.
mismatch repair
A DNA repair mechanism that fixes incorrect base pairings after replication.
deamination
The removal of an amino group from a DNA base, converting cytosine to uracil.
depurination
The loss of a purine base (adenine or guanine) from the DNA backbone.
base excision repair
A repair pathway that removes and replaces damaged bases.
thymine dimer
A DNA lesion where two adjacent thymine bases become covalently linked.
nucleotide excision repair
A repair mechanism that removes bulky DNA lesions like thymine dimers.
double stranded breaks
Breaks in both DNA strands, which can lead to chromosomal damage.
nonhomologous end joining
A repair mechanism that joins broken DNA ends without a template.
homologous recombination
A repair process that uses a homologous DNA sequence as a template.
