DNA replication Flashcards
what happens before cells divide?
DNA is replicated this is known as DNA replication
what is DNA replication?
when DNA is copied before the cell divides
what is semi-conservative replication?
the mechanism by which DNA copies itself
name the mechanism by which DNA replicates itself
semi-conservative replication`
why is the term semi conservative used ?
half of the original DNA molecule is conserved
give general overview of DNA replication
the two strands are separated
both stands act as a template for the formation of a new complementary strand
following replication each DNA stand contains an original strand and one new strand
name the enzymes involved in DNA replication
DNA helicase
DNA polymerase
describe the first step of semi-conservative replication
an enzyme called DNA helicase is required to unwind the DNA double helix by breaking the weak hydrogen bonds between the complementary bases in the polynucleotide strands. this separates the strands
describe what the enzyme DNA helicase is responsible for
separating the stands of DNA by breaking the hydrogen bonds
describe the second stage of semi conservative replication
new DNA nuclotides (present in the nucleus) are attracted to the exposed bases in the template strands, and attach by complementary base pairing. new hydrogen bonds form between the bases
describe the last stage of semi conservative replication
the enzyme DNA polymerase joins the new nucleotides together to form a new polynucleotide strand strand. Phosphodiester bonds are formed between adjacent nucleotides via condensation reactions
describe the role of the enxyme DNA polymerase
joins the new nucleotides together
where did semi conservative replication originate from?
an experiment carried out by Meselson and stahl in 1958
what did Meselson and stahl experiment on?
using bacteria Ecoli
