SLA4Task1 - SLA4 Task 1 A1 Body identification and analysis...

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SLA4 Task 1 A1. Body identification and analysis of forensic material are two other specific uses for DNA testing. A2. Deoxyribonucleic acid, or DNA, contains the genetic instructions utilized in the development and function of all living organisms. DNA is found within the chromosomes in the nucleus of a cell. A right-handed double helix characterizes the structure of DNA with approximately ten nucleotide pairs per each helical turn ( Structure of dna, 2009). Each spiral strand is composed of sugar phosphate scaffolding with attached bases. The complete strand is connected to a complimentary strand through non-covalent bonding between the paired bases: adenine (A) to thymine (T) and guanine (G) to cytosine (C). The bases serve as the genetic instructions that are followed by all cells in the body. A3. Replication is the process DNA undertakes when it copies itself. Through replication, two DNA molecules will be produced from a single double-stranded DNA molecule. Replication follows very distinct steps. First, the double helix of a DNA molecule is unwound so that each DNA strand will act as a pattern for the replication process. The double helix is unwound by the helicase. Once the DNA strand is unwound, RNA nucleotides are inserted at the initiation point by RNA primase (Kyrk, 2010). Within the DNA polymerase, starting at the 3’ end of the RNA primase, matching DNA nucleotides are inserted into the unwound strand. If a mismatched DNA nucleotide is present, the polymerase will not be able to continue the replication. Through proofreading, the mismatched nucleotide is rejected and the proper nucleotide is inserted. The replication continues until the 5’ end of the strand is reached. Upon reaching the 5’ end of the strand, replication ends and the DNA molecule is copied. Where there was once one strand of DNA, two now exist. Occasionally, a mutation within the DNA exists. This can be caused by environmental factors, such as radiation, chemical contaminates, or ultraviolet light. Also, mistakes occasionally occur during the replication process. Environmental factors can alter the shape of the nucleotide bases. This will cause them look like other nucleotides. Then the altered nucleotide will be paired with the incorrect opposing base resulting in a mutation. Sometimes, environmental
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