DNA (Deoxyribonucleic Acid)
Structure of DNADNA is one the nucleic acids, information- containing molecules in the cells. DNA is found in the nucleus of every human cell. DNA may look complicated, but it's simply just a pattern made up of nucleotides. Each nucleotide consists of a sugar (deoxyribose), a phosphate group and a nitrogenous base. There are four bases in the Nitrogenous Base: A - Adenine and T - Thymine; C - Cytosine and G - Guanine.
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Role of DNAAs DNA is a nucleic acid that contains genetic instructions for the development and function of living things, so its main role is to store information in long-term. The information in DNA:
_Guiding the cells in making new proteins that determine all of our biological traits. _Getting passed from one generation the next. |
DNA Extraction MethodDNA Extraction is the removal of deoxyribonucleic acid (DNA) from the cells or viruses in which it normally resides. Extraction of DNA is used to detect bacteria and viruses in the environment as well as diagnosing disease and genetic disorders.
Method: _Buccal swab is used to collect cheek cells. _The cells are then placed into an Eppendorf tube. _Then we put the lysis solution into the tube and put it in a warm water bath. Detergent in the solution helps to disrupt the cell membrane and nuclear envelop, causing the cell to burst open and release DNA. _Then Concentrated salt is used to clump the proteins and other cellular debris. _Using the microcentrifuge to sink the heavy clumps the proteins and other cellular debris to the bottom. _The strands of DNA remain distributed through the liquid. _The alcohol helps to clump DNA so that we can see by our naked eyes. |
GEL ELECTROPHORESIS DNA PROFILING
In Forensics Science, Gel Electrophoresis is used to sort DNA strands according to the length. The scientist also use it to separate other types of molecules such as RNA and Proteins. Restriction Enzyme is used to cut DNA. "Gel" in Gel Electrophoresis is a filter that sort the DNA strands.
DNA samples are collected then placed into holes at one end of the gel. Then Electrophoresis to add an electrical current. Because DNA is negatively charged so the samples are placed at the negative end so that when the current goes through they will move to the positive end. Short strands move faster than long strands. The same length strands will move at the same speed and end up grouped. |
DNA Profiling (also called DNA fingerprinting, DNA testing or DNA typing) is a technique used in Forensics Science to identify individuals by characteristics of their DNA. this technique is very helpful in identifying a criminal at a crime scene and the victims. It also means the process where a specific DNA pattern, called a profile, is obtained from a person or sample or bodily tissue. Human DNA profiles can be used to identify the origin of a DNA sample at a crime scene, or test for parentage.
What is a DNA profile? To produce a DNA profile, scientists examine STRs at ten, or more, genetic loci. These genetic loci are usually on different chromosomes. A DNA profile can tell the scientist if the DNA is from a man or woman, and if the sample being tested belongs to a particular person. |