brought to you by: Wongsakorn C. and Shermera D.
DNA, or deoxyribonucleic acid, is the genetic material that organisms inherit from their parents which is located in the cell nucleus. It has a double-stranded helical macromolecules consisting of nucleotide monomers with deoxyribose sugar and the nitrogen bases; adenine (A), cytosine (C), guanine (G), and thymine (T). The two DNA chains are held in a double helix by hydrogen bonds between their paired bases; G with C and A with T. One long DNA molecule may contain many genes, each a specific series of hundred or thousands of nucleotides along one of the polynucleotide strands.
During cell division, DNA is replicated itself and can be transmitted to the offspring through during reproduction. DNA has the duty to make genes. DNA replication is the process of copying the double-stranded DNA prior to cell division. DNA also takes part in the process of making proteins. There are three stages of making protein; there are replication, transcription, and translation. First, DNA (A, T, C, and G) replicates itself (T, G, A, and C). Then, DNA transcribes itself into mRNA (A, C, U, and G). Next, mRNA enters the cytoplasm and binds to a ribosome. Then, tRNA carries amino acid to the ribosome according to the three-base codon during translation. As the mRNA passes through the ribosome, the amino acids delivered by tRNA are added to the end of the growing protein chain. When the end of the mRNA sequence is reached, the newly made protein is released into cell. This is how DNA involves in protein-making process.
DNA fingerprint can be used to solve crimes and paternity questions. DNA fingerprinting is produced by a DNA technology called electrophoresis. Electrophoresis is a powerful technique to separate, identify, and compare patterns of gene fragments from DNA samples. DNA fingerprint is the specific pattern of bands that show up on the crime scene. DNA fingerprint can be represented to juries in the murder trial as evidence. If the DNA pattern of the defendant is matched with the DNA blood pattern that is on the crime scene. That means the defendant is guilty. DNA fingerprint can also be used to establish family relationships. A comparison of the DNA of a mother, her child, and the purported father can conclusively settle a question of paternity. For example, DNA fingerprinting provided the strong evidence that Thomas Jefferson or one of his close male relatives fathered at least one child of slave. DNA is used in recombinant DNA technology. A recombinant DNA technology is a set of laboratory techniques for combining genes from different sources or even different species. It is now widely used to alter the genes of many types of cells for practical purpose. For example, genes have been transferred from bacteria into plants and from humans into farm animals. The products from the recombination DNA are human insulin from bacteria, human growth hormone, taxol, epidermal growth, a mouse that grows as big as a rat, and the increases in production of modified plants.