Replication Flashcards
DNA replication
Copying of DNA content every time the cell divides resulting in identical copies of chromosome pairs in each daughter cell
Semi-conservative
Each polynucleotide strand acts as a template to form a complementary strand
DNA polymerase
Synthesizes complementary strand using single stranded DNA
RNA polymerase
Synthesizes RNA primers
DNA polymerase lll
Carries out most of DNA replication
DNA polymerase l
Used in DNA repair and removes primers
Replisome
Multi-protein complex where replication takes place
Gyrase
Type II Topo which unwinds DNA
Helicase
Separates the stands
Single stranded binding protein
Keeps strands from renaturing
DNA ligase
Links Okazaki fragments
Topoisomerase
Enzyme that alters the topological state of DNA
Linking number
Number of times 1 strand winds around the other in a complete circle in a right - hand direction
Type I Topo
Cleaves 1 strand and doesn’t need energy
Type II Topo
Cleaves both strands and requires energy
DNA pol alpha
Replicates chromosomal DNA, has primase activity, lacks endonuclease activity, and is the lagging strand replicase
DNA pol delta
Is the leading strand replicase, lacks primase activity and has exonuclease activity
DNA pol beta
Involved in DNA repair
DNA pol gamma
Replicates mitochondrial DNA
DNA repair
Protects against external damaging agents to prevent mutation
Direct repair
Reverses damages using enzymes
Nucleotide excision repair
Endonuclease cleaves damage and pol I removes it and fills gap which is then sealed by DNA ligase
Telomeres
Made up of G-rich DNA repeats and proteins found at the ends of chromosomes, it prevents degradation and recombination
Telomerase
Made of up a reverse transcriptase and RNA template and proteins, it maintains telomere length
