Studied by 1 person
dna replication
the production of new strands of dna, rewuired for reproduction, growth and tissue replacment
semi conservative nature of dna
when dna is replicated, the 2 strands of the double helix must seperate, both strands r used as templates, new strands are formed by adding nucleotides one by one and linking them together, dna is semi conservitive bc there are 2 dna molecules, compsed of an og template strand and a new synthesized strand
role of helicase
ring shaped protein that seperates the 2 strands of dna by breaking hydrogen bonds
role of dna polymerase
assembles new strands of dna using the 2 og strands at templates, dna polymerase brinds nucletides into the position whith hydrogen bonds, links the nucletide to the end f=of the new strand
polymerase chain reaction (PRC)
an automated method of dna replication, mixtures of dna sequences r put inot the PCR machine
applications of polymerase chain reaction
can be used for covid + paternity testing
pros and cons of polymerase chain reaction
pros- sensitve+ specific
cons- expensive, slow
dna profiling for paternity testing
this technique of dna profiling distinguishes individuals using bade sequences known as short tandem repeats
a sample of sna is obtained, selective tandem repeats r copied by PCR, dna is prodcued by PCR
how nucleotides r linked together
nucleotides r linked to form strands of dna+rna with covalent bonds between the sugar of one nucleotide and the phosphate of the next
diferences in leading strand and lagging strand
dna strands r anti-paralell, in a 5’ to 3’ direction
on one strand, dna polymerase adds nucleotides towards the replication fork, on the other strand dna polymerase adds nucleotides moving away from the replication fork
functions of dna primase
dna primase is a type of rna polymerase
it assembles a chain of ab 10 rna nucleotides to provide a site where dna polymerase III can bind and stard adding nucleotides to the 3’ of a dna strand
dna polymeras III
the principal polymerase in dna replication
it binds to the template strand on the 3’ end of the rna primer and assembles a chain of dna nucleotides and it also proofreads each nucleotide
dna polymerase I
binds to an okazaki fragment on a lagging strand
removes rna nucleotides and replaces them w dna nucleotides
dna ligase
connects the gaps in the chain of nucleotides left by dna polymerase
dna proofreading
errors are corrected, preventing mutations
proofreading happens durinig replication immidetily after a wrong nucleotide has been place
done by the dna polymerase III
Note 
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