DNA can be one of the most complicated cells and molecules inside our body. They can replicate and produce the same DNA molecules. However, it is still a big question which DNA strand is synthesized continuously. Let’s check our article below to get you closer to the answer.
What is DNA replication? Well, some of you may still an eyebrow reading this. Replication is actually a process that the DNA molecule is replicated in order to have two identical molecules of DNA. This kind of replication is the most fundamental processes that happen inside a cell.
Every time a cell in the body divides, the two cells’ genetic will be exactly the same related to DNA or information as the cell from the parents. In order to do this process successfully, every strand’s DNA that exists will act as a replication’s template.
The process of how DNA replicates
There are three steps inside the process of how DNA replication happens in order to answer which DNA strand is synthesized continuously. The first step is when the double helix opens and when the DNA strands separate. The second step is the priming process of the strands’ template. The last step is when the segment of new DNA assembles.
First of all, let’s talk about the moment when the two DNA’s strands separate. During the separation, the double helix will uncoil in a certain area. This area is sometimes known as the origin. After that, some proteins and enzyme cooperate together to prime or prepare before the strands are ready to be duplicated. Last but not last, DNA polymerase which is a special enzyme, arranges the new DNA strands’ assembly. Generally, all cells have these three-stage processes, however, it is possible to have different variations inside the process may happen. It all depends on the type of the cell and the organism.
Things that trigger replication
There are two steps behind the DNA replication initiation. First, there is an initiator protein which undoes DNA double helix’s short stretch. After that, a protein that is called as helicase will connect to and break the bonds of hydrogen apart between the DNA strands’ bases. It will make the two strands pull apart. When the helicase moves the molecule of DNA along, it continues to break the bonds of hydrogen and separate the chains of two polynucleotides.
While the strands are separated by the helicase, primase, another enzyme, attaches itself to every strand. After that, this enzyme attaches a base which starts the replication process. This base is a stretch that contains nucleotides. This base is also known as a primer.
The DNA strands replication process
There are many schematics that can show you an area of horizontal DNA single-stranded. To make you easier to process, let’s break it down one by one. There is a transparent area that has a globular structure in blue color. This area represents the enzyme of DNA polymerase which is bound to a region that is 7-nucleotides-long. This area can be found in your right side in the strands of DNA. The area where DNA polymerase is bound by DNA can be seen within the transparent enzyme. Of course, it needs to be in a higher magnification. In this area, there are around six nucleotides too. Those nucleotides are bound to another six supporting nucleotides organized above an in parallel to a strand. It forms blue-orange or red-green pairs. Later, there will be around two dozen individual nucleotides float which DNA strand is synthesized continuously.
DNA polymerase covered itself that is surrounded by strand after the primer in the right place on unwound, single polynucleotide strand. It connects to the new nucleotides to the bases of exposed nitrogenous. This process will make the polymerase creates a new strand of DNA on the top of the DNA strand that already exists.
The difference between continuous and discontinuous DNA synthesis
After we find out which DNA strand is synthesized continuously, it is the time to look at the difference between continuous and discontinuous DNA synthesis. Actually, in nature, the replication of DNA is semi-conservative. DNA is comprised of a helical base with double-stranded which contain nucleotides. In the starting point of the replication process, that double DNA strand separates into two strands that are single that can be replicated. Every one of the two strands is then copied that produce in two new DNA strands from the helix of the parent as preserving the authentic foundation sequence from the strand of the parents.
Continuous replication of DNA
In the continuous replication process of DNA, the parents’ DNA strands separate in the beginning process of replication. The double helix split first at the replication origin or an internal point. The strand from one parent is aligned in a 4’ to 3’ direction meanwhile another strand is aligned in the configuration of a mirror from 4’ to 5’ direction. However, the enzyme that has a responsibility to provide replication, DNA polymerase, works only in the 5’ to 3’ direction. So, it explains which the strands of the daughter have to replicate in the two ways that are not the same.
Ideally, the orientation of the strand’s replication can happen continuously. It has progress that has the same direction as the fork of replication. It contains nucleotides that are added step by step. The strand of the daughter that copies in this way is connected to the main strand.
Discontinuous replication of DNA
Meanwhile, in the remaining strands of the daughter, they are oriented in the direction of 3’ to 5’ antiparallel way. Since a molecule of polymerase is only able to work in a parallel way, the replication of DNA on this very strand can happen only in parts or fragments that are separated from the fork’s replication. Ozaki fragments, the antiparallel chunks of lagging strand, are copied in the prime direction which is 5’ to 3’. It moves back to the fork of the replication. Later on, all of those fragments will be together because of the DNA ligase enzyme that can create a strand that works continuously.
In conclusion, DNA ligase, which DNA strand is synthesized continuously, work together with Ozaki fragment to keep doing its replication. By knowing this information, we hope that it can add your knowledge and fulfill your curiosity.