DNA
A persons gender, eye colour, hair and skin colour are determined by their DNA
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What is DNA?
DNA is short for deoxyribonucleic acid and is a molecule found in the cells of all living organisms. The majority of an organism's DNA is found in the Nucleus of the cell. The genetic information stored in the cell's DNA dictates the structure and function of the cell. The structure of DNA in humans can be described as long strands with an approximate length of 2-3 meters and width of 2- millionths of a millimeter. As the DNA molecules are so long, they bind to special proteins called histones. These proteins act as structures in which DNA strands can coil around, allowing them to reduce surface area and fit into small spaces like the nucleolus.
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Below is a link to an interactive game about the strucutral components of a strand of DNA, as well as the process of translation and transciption
DNA Replication
When a cell reproduces, the inherited information stored in the nucleus must be replicated to ensure that the genetic code is passed on unchanged to the cells produced. This process of DNA replication occurs during a period known as interphase and results in two identical strands of DNA. The creation of these identical strands of DNA starts with the separation of the two strands of the original DNA, this is able to occur due to weak bond between the nitrogenous base pairs. Special enzymes called DNA helicase, these enzymes separate the double stranded DNA into single strands allowing each to be replicated.
This separation results in each section containing half the original information. the two split strands of the original strand serve as a template for the nucleotides that will form the new half. As nitrogenous bases can only act in pairs (A-T, C-G) the new strand of DNA is able to form by reading what nitrogenous base is on the original strand and matching it to its relevant base. This process is possible due to the presence of DNA polymerases. DNA polymerase is an enzyme that creates DNA molecules by assembling nucleotides. Then end result is two identical strands of DNA. |