วันศุกร์ที่ 15 เมษายน พ.ศ. 2554

structure of dna

structure of dna


In all that we see in nature, the principle that we usually see is that form follows function. This is because in almost all creatures and plants, the unique features that they have serve a purpose. One example of this includes how some creatures are able to camouflage themselves within their background because their skin color allows them to do so. Other examples include birds with specially shaped beaks to help them catch prey, and the woodpecker is a good example of this. However, this principle does not only apply to the physical attributes of animals and plants as this principle is also followed up to the molecular level. This is seen on how the structure of the most basic genetic molecule, which is DNA also follows this principle.

Form follows function

The function of DNA is for replication and the transfer of genetic information. Given this, it can be expected that the structure of DNA would be designed to serve these functions. For its replication function, the two-strand structure of DNA molecule allows for the separation of these two strands to be able to bind with newly developing DNA molecule. This means that the two strands can "give birth" to a limitless number of DNA molecules as long as the replication process goes on.

For its genetic information transfer function, the way by which DNA molecule is made up of sub-units that contain a sugar, a phosphate group and four nitrogenous bases allows for the molecule to be arranged in a way by which a code is formed. This code is determined by the sequence of the four nitrogenous bases namely, adenosine (A), cytosine (C), thymine (T), and guanine (G). During the replication process, this code is transferred to the new DNA molecules that are formed through a process by which a gene that is formed or coded in the same sequence in which the nitrogenous bases are sequenced in the DNA. These genes then determine the proteins that make up and establish the biological characteristics of an organism.

As with anything in nature, DNA also follows the principle that form follows function. This is because the unique structure of DNA allows it to serve its two main functions, which are the replication and the transfer of genetic information.

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