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DNA Replication - Lesson Summary

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Page 1
Helicase is a protein that unfolds, opens up or unwinds a portion of the DNA within a biological system.
Single-stranded Binding protein (SSB protein) bind to the single strands of DNA in the replication fork and prevent them from rehybridizing.
DNA polymerase is an enzyme that helps to synthesize the complementary strand of a bifurcated DNA strand.
DNA ligase is an enzyme that joins or stiches together newly synthesized DNA strands.
Controlled DNA synthesis always occurs in the 5' to 3' direction.
Okazaki fragments are pieces of DNA that are components of the lagging strand of the replication fork during DNA synthesis.
A DNA is split in the laboratory by heating it at 95 degree Celsius. This breaks all the non-covalent interactions.
In the laboratory synthesis of DNA, helicase, SSB protein, RNA primase and DNA ligase are not required.
The ingredients that need to be fed into the PCR machine are, the DNA sample, taq polymerase, oligonucleotides (2 DNA primers), dNTPs and magnesium chloride buffer solution.
The DNA primers are usually 15 to 20 bases long.
Taq polymerase is a thermostable DNA polymerase isolated from a thermophilic bacterium, Thermos aquaticus, found in hot springs.

Page 2
Polymerase Chain Reaction runs in three different stages:
Denaturation
Annealing
Extension

The Nobel Laureate scientist, Frederick Sanger devised the di-deoxy method of analyzing the sequence of nucleobases of a given DNA.
Sanger's method uses the same idea as DNA replication. The only difference is that it uses a single-stranded DNA instead of a double-stranded DNA.
Sanger's method uses a molecule called di-deoxy ribose nucleotide triphosphate.
Sanger's method also is known as the chain termination method because the reaction stops at a point.
Gel electrophoresis or autoradiogram is used to read the DNA sequence identified by Sanger's method.