DNA replication Flashcards
How is DNA READ
3’ to 5’
How is DNA CONSTRCTED
5’ to 3’
What are the three stages of DNA
1) Intiation
2) Elongation
3) Termination
Where does DNA replication occur
Nuecleus - eukaryotes
Cytoplasm - procarytes
When does DNA replication occur
During interphase.
Use of DNA Gyrase
Removes tension from double helix structure of DNA
Use of inhibiter protiens
Flattens out DNA
Use of DNA helicase
Breaks H bonds holding nitrogenous bases together
What makes up a nuecleotide?
Deoxyribose penthouse sugar, phosphate group, nitrogonus base
What does adenine pair with?
Thymine
What does cytosine pair with?
Guanine
What stops base pairs from reconnecting once broken
Single Stranded DNA binding protiens
What is the role of primase
Labels where polymerase III should start connecting complimentry base pairs
Purpose of:
Polymerase I
Polymerase II
Polymerase Ill
Polymerase I - Deletes RNA from primase once base pairs are connected AND proof reads DNA for mistakes
Polymerase II - Proof reads DNA for mistakes
Polymerase Ill - Pairs nitrogonous bases
How does DNA replication occur (which direction)
Bilaterally (from both sides of replication bubble)
What does ligase do?
Joins ogasaki fragments together with phosphidester bonds.
What are okasaki fragments?
Short Sequences of DNA
Describe leading VS lagging strand
DNA is inverly proportional, meaning as one side is listed 3’ to 5’, the other is 5’ to 3’.
DNA must always be replicated 5’ to 5’.
- Leading: Helicase is breaking bonds 5’ to 3’ so Polymerase III can continously pair nitrogonous bases without breakage
- Legging: Helicase is breaking 3’ to 5’ so polymerase III must start at primase closest to helicase and pair bonds. As helicase moves, a new primase will be set up closer and polymerase III will continue pairing bonds making okazaki fragments.
How is primase broken down?
RNA removed by polymerase I and nitrogenous bases paired by polymerase III
How is quality control done for DNA
Polymerase I and II quality check all pairs to make sure they are correctly matched up
How do DNAs dismantal
Helicases reach at a fork, breaking the replication bubble
What type of replication is DNA considered
Semi-conservative
What do the new strands of DNA include
1 strand of parent DNA and 1 copy
What are telomeres
Noncoding regions at end of DNA that act as buffer to protect gene coding. Protects DNA from getting shorter each replication
Why is DNA replication important
Cells could not grow or reproduce without DNA replication
How many telomeres are lost per replication
100 base pairs
