Proteins and Enzymes
Synthesizes new DNA molecules by adding nucleotides to leading and lagging DNA strands.
DNA polymerases
Structure of DNA
Double Helix
A bonds with T and C bonds with G
Complementary Base Pairing
During DNA replication, most DNA polymerases check their work fixing the majority of mispaired bases.
Proofreading
1 single circular chromosomes
Unwinds and separates double-stranded DNA strands as it moves along the DNA. Forms replication fork by by breaking hydrogen bonds between the nucleotides in DNA.
DNA Helicase
Joins base pairs together
Hydrogen bonds
Each strand of the original double helix serves as a template for a new strand in a daughter molecule.
Semiconservative replication
Immediately after DNA synthesis, any remaining mispaired can be detected and replaced.
Mismatch repair
Prokaryotic DNA division produces:
2 identical circular chromosomes
A type of RNA polymerase that generates RNA primers, which are short RNA molecules that act as templates for the starting point of DNA replication.
DNA Primase
Adenine and guanine
purines
DNA is replicated from:
5' to 3'
How many origins of replication in eukaryotic DNA replication
Multiple
How many origins of replication in prokaryotic DNA replication?
One
Unwinds and rewind DNA strands to prevent the DNA from becoming tangled or supercoiled.
Topoisomerase
Thymine and cytosine
Pyrimidines
DNA is read from:
3' to 5'
Prevents supercoiling in eukaryotic DNA replication
Topoisomerase
DNA replication and cell division time problem in prokaryotes
DNA replication takes 40 mins, but cell divides every 20 minutes, so a new round of replication is started before the one before is completed.
Attaches to newly separated DNA strands to prevent helix from re-forming.
Single-stranded binding proteins
The amount of adenine is equal to the amount of thymine, and the amount of cytosine is equal to the amount of guanine.
Chargaff's Rule
Fragments on the lagging strand that joined together.
Okazaki fragments
Ways DNA is repaired
Chemical reversal, excision repair, double-stranded break repair
Prevents supercoiling in prokaryotes.
DNA gyrase