Background Information
DNA Replication is the process of copying a strand of DNA prior to cell division. It is structurally a polymer, it is made up of many small repeating molecular units which in DNA are called nucleotides and when you put many nucleotides together they are called polynucleotides.
DNA is never found as a single nucleotide molecule but rather a double molecule that take the shape of a twisted ladder known as the double helix. It is formed with two twin backbones of phosphate groups and carbon sugar molecules (deoxyribose) that go in opposing directions (see figure 2).
One strand begins at the first Phosphate connecting to the sugar molecules 5th carbon and ends where the next phosphate would go at the end of the sugar molecules 3rd carbon. This creates the pattern [5’-->3’] while the other strand going in the opposing direction creates the pattern [3’--> 5’] (see figure 3). As for the types of Bases all you have to remember is that Adenine can only pair with Thymine (2 hydrogen bonds) and Guanine can only pair with Cytosine (3 hydrogen bonds)and vice versa (see figure 4). These are called base pairs. When you put together a Pattern of base pairs you create a Base sequence which allows your DNA to make you.
Replication
Replication
The replication occurs when the enzyme Helicase splits the gene strands apart at the replication fork (see figure 5). It splits into 2 strands the top strand or leading strand and the bottom strand or lagging strand. Using these 2 new strands as templates you can replicate DNA.
The replication occurs when the enzyme Helicase splits the gene strands apart at the replication fork (see figure 5). It splits into 2 strands the top strand or leading strand and the bottom strand or lagging strand. Using these 2 new strands as templates you can replicate DNA.
The Leading Strand
To replicate the leading strand is much easier than the lagging strand; it first starts with a primer called RNA Primase, this adds matching nucleotides to fill the unzipped section. Then DNA polymerase adds matching nucleotides on the main stem the whole way down the molecule. (see figure 6 &7)
The Lagging Strand
As simple as the leading strand sounds, it is not nearly as easy for the Lagging strand. To replicate this strand first a RNA primase is done in segments that are called Okazaki fragments. These allow the strand to synthesize in short bursts (named after a married couple who discovered it). DNA polymerase then works backwards on the segments this is done in a ton of segments each about 1,000 to 2,000 base pairs long. After that another DNA polymerase goes over to change the RNA Primers. The last step is for DNA ligase to run through and join up the fragments. (see figure , 8, 9,10,11&12)
DNA replication is wrong about 1 every 10 billion nucleotides but thankfully DNA polymerase proof reads the strand and fixes any mismatched base pairs.
How does it relate to the conservation of genetic information?
DNA replication has a lot to do with conserving genetic information because it copies the DNA strand. It make a replication of that exact genetic info, which means there is more of that certain type of information. It copies the DNA so there is no longer just one but many more and it becomes harder to loose the genetic information. DNA replication also helps transmit that certain type of genetic information because when there is not just one copie it is easier to find research and give out.