DNA replication Flashcards
DNA can be described as a ……..-……………. process
semi-conservative
Summarise DNA replication
helicase enzyme breaks hydrogen bonds between base pairs, unwinding the double helix
DNA polymerase builds new strands of DNA by adding free nucleotides together while using the original strands as a template
Describe the bonding of nucleotides
a phosphodiester bond is formed between the 5’ carbon of the deoxyribose sugar of one nucelotide and the hydroxyl group on the 3’ carbon on the deoxyribose of another nucleotide.
What directionality does DNA building occur in?
5’ to 3’
What is the leading strand?
The DNA strand synthesized continuously in the 5’ to 3’ direction
what is the lagging strand?
The DNA strand synthesized discontinuously in short Okazaki fragments
What does SSBP (Single-strand DNA-binding protein) do?
prevent strands from reattaching
what does DNA gyrase do?
relieve tensions caused by the unwinding
What does DNA primase do?
attach RNA primers to template strand so DNA polymerase can attach + begin assembly. Attached several times on the lagging strand.
What does DNA polymerase 3 do?
build the new strands of DNA
What does polymerase 1 do?
removes RNA primers + replaces them with DNA nucleotides.
What does DNA ligase do?
Join okazaki fragments together
