DNA, protein And The Central Dogma Flashcards
Which nucleotides pair together?
Adenine-Thymine (or Uracil for RNA)
Guanine-Cytosine
What is the job of the helicase?
Break the parental double helix at the separation fork
Which enzyme unzips DNA?
Helicase
What stabilises the unwound DNA?
Binding protein
What does the binding protein do?
Stabilises the template strands
Why is DNA replication called semi conservative?
Because one strand is made up of conserved DNA
What is the job of a topoisomerase?
To break, swivel and rejoin the parental strand to fix it being too wound up
Which enzyme fixes the DNA being too wound up?
Topoisomerase
What does the primase do?
Places a RNA primer to begin synthesis of the okazaki fragment for a lagging strand and a single RNA primer on the leading strand
Which enzyme places the primers for the Okazaki fragments?
Primase
What does DNA polymerase 3 do?
Leading: continuously synthesises in the 5’ 3’ direction
Lagging: synthesises fragments by finding the RNA primer and completing the Okazaki fragment
What does polymerase 1 do?
Removes the RNA primer from the 5’ fragment and replaceling it with nucleotides, leaving the end open
Which enzyme removes the primer and replaces it with nucleotides?
DNA polymerase 1
What does DNA ligase do?
Leading: joins the open 3’ and 5’ ends together
Lagging: does the same within the Okazaki fragments
Which enzyme joins the 3’ and 5’ together in DNA synthesis?
DNA Ligase
What bond holds DNA nucleotides together?
A weak hydrogen bond (not covalent)
Why is DNA held together with a weak hydrogen bond?
Because DNA needs to break apart and remake itself a lot, so the bond needs to be easy to break and reattach together, using minimal energy