D1.1 DNA replication Flashcards
What is semi-conservative replication?
Two DNA strands that each one consists of one parent strand and one new strand.
What helicase does?
This enzyme breaks down the hydrogen bonds between the bases
What DNA polymerase does?
This enzyme connects the free nucleotides to form new strand
How DNA polymerase connects the nucleotides?
it creates the bond between the phosphate of new nucleotide to the sugar of the last nucleotide
What is polymerase chain reaction (PCR)?
technique to amplify (rozszerzac) small fragments of DNA
How DNA strand is separated by breaking hydrogen bonds in PCR?
Using heat (>98C)
What is primer? (PCR)
short DNA sequence that ensures the replication from the desired point
Taq polymerase (PCR)
heat-tolerant DNA polymerase
Describe the PCR.
-the DNA is heated to break the hydrogen bonds between the complementary bases and separate the strands
-the primer is added and bonds to the bases on the DNA sample
-the Taq polymerase replicates the DNA using a primer as a starting point
What is gel electrolysis for?
it separates molecules by length
Name two examples of application of PCR and electrophoresis
paternity testing, testing for coronaviruses
How do you find out the parent of the child from banding patterns?
-child gets half the DNA from mother and half from father
-look for DNA piece (one strand) that is present in child but not in the mother, this fragment will be found on the other parent-this is the father
In which direction replication happen?
in 5’ to 3’, new nucleotides can only be added to the 3’ end
How to identify leading strand?
it goes from 3’ to 5’
How to identify lagging strand?
nucleotides are added in 5’ to 3’ direction in short fragments (Okazaki fragments)
What is the function of DNA primase?
it lays down a RNA primer (fragment) to signal other enzymes where to start replication
What DNA polymerase III does?
it adds new nucleotides on the leading and lagging strands (in 5’ to 3’ direction) and connects them
How DNA polymerase III attaches nucleotides together?
it creates a bond between the phosphate and sugar
What’s the function of DNA polymerase I?
it removes the RNA primers and replaces with correct DNA nucleotides
What’s the function of DNA ligase?
it connects the Okazaki fragments by connecting phosphate and sugar
What is proofreading?
when DNA polymerase III recognises the mistake and replace wrong nucleotide with the right one
