DNA Replication 3.9 Flashcards
DNA replication
When one strand of DNA unzips and it’s exposed bases will be joined by free nucleotides to produce two genetically identical strands of DNA
Semi-conservative DNA
One strand is the old parental DNA strand and the other strand is the newly replicated one
DNA helicase
The enzyme responsible for breaking the hydrogen bonds between bases to unzip the DNA strand
DNA polymerase
The enzyme responsible for synthesising the phosphodiester bonds between the newly joined nucleotides
Continuous replication
The strand that goes 3’ to 5’ is the leading strand as DNA polymerase travels in the right direction and can connect all the nucleotides continuously.
Discontinuous replication
The strand that goes 5’ to 3’ is the lagging strand as the DNA polymerase travels in the opposite direction so will only synthesis little sections of DNA at a time when there;s an unzipping of the strand. This creates Okazaki fragments
Mutations
When there is an error in the replication of DNA that results from the sequence being read incorrectly
Genetic code
A sequence of DNA bases that code for an amino acid which in turn will code for a protein
Triplet code
A codon which is three bases and each codon codes for one amino acid
Degenerate code
The fact that many codons will code for one specific amino acid because there are more possibilities of codons than amino acids