DNA is an abbreviation that stands for deoxyribonucleic acid. It stores genetic materials, thereby determining the genetic characteristics of individuals. It is composed of genetic instructions which program the entire body activities.
A nucleotide is made up of three parts including a 5-carbon sugar molecule (deoxyribose), 1 of the four nitrogen bases, and a phosphate group.
Delegate your assignment to our experts and they will do the rest.
The nitrogenous base is the part which carries information. The sugar is responsible for bonding with the next molecule when the oxygen atom is exposed. Phosphate group forms part of ATP, which is an energy molecule.
The four nitrogen bases comprise Guanine, Cytosine, Adenine, and Thymine.
DNA is referred to as a double helix because the polynucleotide molecule that forms it does not exist singly instead as a pair of molecules that are tightly held together. They appear to be intertwined, creating a double spiral staircase.
DNA is antiparallel because it comprises pairs of molecules that lie side by side and run in opposite directions.
Base pairs are nitrogenous bases which are bonded like Guanine bonding with Cytosine (G-C) and Adenine bonded to Thymine (A-T). The G-C pair comprises of three hydrogen bonds; thus, stronger than the A-T pair (Crash Course Biology, 2012, 3:45).
Base pairs exist in hydrogen bonds for complementary purposes during DNA replication.
A base sequence is the order of the four nucleobases. It in charge of DNA creating an individual (Crash Course Biology, 2012, 4:13).
The corresponding strand for a TAGCCATTG of a base sequence is ATCGCTAAC because only Adenine can pair with thymine whereas guanine pairs with cytosine.
One difference between RNA and DNA is that RNA lacks a double helix, a single-stranded molecule whereas a DNA has a double helix. Secondly, RNA consists of ribose as sugar that has an extra oxygen atom compared to deoxyribose in the DNA (Crash Course Biology, 2012, 5:43). Lastly, RNA lacks thymine, but it is replaced with Uracil which bonds with Adenine, unlike the DNA.
DNA Replication is the constant division of cells to form a same complete copy of DNA with DNA information.
Helicase is an enzyme which aids the separation of double-stranded DNA to single strands for the copying of each strand (Crash Course Biology, 2012, 9:22). Therefore, it is vital in DNA replication.
A leading strand is the top strand of the replication fork, whereas the lagging strand is the bottom strand of the replication fork (Crash Course Biology, 2012, 9:38).
DNA Polymerase is an enzyme that occurs on the leading strand to add up matching nucleotides to the main stem down the molecule.
A primer provides a surface for a DNA polymerase to hook onto to start building a new DNA chain (Crash Course Biology, 2012, 1:53).
RNA primase is an enzyme responsible for laying down the occasional primer to give the DNA polymerase a starting point after which it works backward along the strand (Crash Course Biology, 2012, 10:24).
Okazaki Fragments are short sequences of DNA nucleotides, which are synthesized irregularly ( Crash Course Biology, 2012, 11:07). Later, they are connected by the DNA ligase enzyme for the formation of lagging strand during DNA replication.
The lagging strands go through continuous replication because they have the 3’ and 5’ strand directionality; thus allowing the polymerase to assemble it without interruption to follow the replication fork. Nonetheless, the lagging strands do not replicate constantly because the strands have a 5’ and 3’ strands.
DNA ligase is an enzyme responsible for facilitating the joining of strands of DNA (Crash Course Biology, 2012, 11:47). It does this by catalyzing the formation of a bond. Moreover, it has a role in the repair of broken single or double strands.
In some cases, mistakes happen such that DNA replication gets wrong. It occurs once among 10 billion nucleotides. However, the body has a proper way of rectifying such mistakes. The nucleotides in the incompatible base are removed from the strand's end.
The phase of mitosis that DNA replicates in is the S-phase, that is, the synthesis phase of interphase where cell division planning happens. At the interphase, there is growth, development, and regular function during mitosis.
Reference
Crash Course Biology. (2012). DNA Structure and Replication: Crash Course Biology #10 [Video]. Retrieved from https://www.youtube.com/watch?v=8kK2zwjRV0M&feature=youtu.be
