How DNA replicates Flashcards
What is DNA polymerase?
An enzyme that catalyses the formation (polymerisation) of DNA from activated deoxyribose nucleotides.
What does helicase do?
Catalyses the breaking of hydrogen bonds between the nitrogenous pairs of bases in a DNA molecule.
What is semi-conservative replication?
When part of the old thing that is being replicated is a part of the new things. In DNA one old strand is conserved in each molecule.
When the DNA unwinds the double helix is untwisted a bit at a time. This is catalysed by what enzyme?
Gyrase
What becomes exposed when the DNA unzips?
The nucleotide bases.
When the DNA is unzipped by helicase what is made as a result?
Two strands of DNA
What binds to the exposed nucleotide bases?
Free floating nucleotide bases
DNA polymerase catalyses what?
The addition of the new free floating nucleotide bases.
How are the leading and lagging strands synthesised?
The leading strand is synthesised continuously whereas the lagging strand is synthesised in fragments.
Which enzyme brings the leading and lagging strands back together in the end?
Ligase
Hydrolysis of the activated nucleotides releases phosphate group which releases energy. What is this energy used for?
To create the phosphodiester bonds.
