KA2 Structure And Function Of DNA Flashcards
What are stages 1 2 and 3 of DNA replication
1-DNA unwinds and unzips as hydrogen bonds break, exposing 2 template strands
2- primers attach to the 3’ end of template strand and DNA polymerase enzymes bind
3- DNA polymerase moves along adding free complementary DNA nucleotides to the 3’ of the new strand
What are stages 4 and 5 of DNA replication
4- the leading strand is made continuously as DNA polymerase can only add nucleotides to the 3’ end of the new strand
5- because 85 is anti parallel to the leading strand, the lagging strand is made is fragments then joined by ligase
What is DNA polymerase
Binds to primer
Enzyme that builds up the new strand of DNA by adding nucleotides to the DNA template
What are primers
A short strand which is already made complementary
What is DNA free nucleotides
They float free into the nucleus and the base of this will bind with the complementary base
What is DNA ligase
Enzyme that will join the DNA fragment
What is the DNA template
The original double strand has to unzip to allow replication to happen
When does DNA replication occur
Occurs prior to cell devision to make sure all daughter cells get a identical copy of all the DNA allowing them to function properly
What does it mean by ‘amplifying’
Production of multiple copies of the DNA sequence
What are the stages of PCR
DNA is taken to between 92-98°c which separates the strands
DNA is then cooled between 50-60°c allowing the complementary primers to bind to a specific target sequence
Temperature is then raised to 70-80°c where heat tolerant DNA polymerase is used to synthesis new strands
What is PCR repeated 25-35 times
To produce millions of copies
What does gel electronphesis produce
Unique DNA fingerprints of a individual
What is DNA replication
Formation of copies of DNA molecules
What is the base pair rule
Adenine- thymine
Guanine-cytosine
What molecule contains the 3’
Deoxyribose sugar
