Dna Gel Electrophoresis Lab Report

This experiment will be done as the first step in determining an unknown protein. The second part of the protein determination will be done using the Western blot technique. We will use the Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) method to separate proteins by their molecular weight. This method is often used to determine the purity and weight of a protein. Electrophoresis is a method of separating proteins based on their chemical and physical properties. Gel electrophoresis has a gel support mediums that includes polyacrylamide, starch and agarose. The gel is chemically inert, it is easy to handle, and can me made to fit a desirable porosity. This makes it good to use for molecules with high molecular weights. After separating the gel, it will be stained with Coomassie Blue to visualize the protein.

Today in the crime world, DNA evidence is strongly accepted in solving crime cases. This is all based in part by allowing a crime laboratory to have a designated unit whose main goal is to analyze DNA evidence to aid investigators with positive outcomes in crime case solving. With that being said we are going to discuss the functions of a DNA unit within a crime lab as well as address the vital role these units play in solving crime.

Shortly after the crime, suspect 1 was detained selling an autographed jersey at a pawn shop. We received a sample of DNA from suspect 1. Mr. Woolford also mentioned a severe jealousy issue that suspect 2 had of Mr. Woolford, that he had not won the jersey instead. Due to jealousy being a motive, we took a sample of DNA from suspect 2 as well to compare to the crime scene DNA.

Using the electric current, scientists pass the DNA through gel, and as smaller molecules get through gel quicker than those of bigger sizes, DNA molecules get separated according the sizes of the molecules. We utilize the property that large molecules move slower, and DNA is slightly negatively charged(due to phosphate groups), so it will move to the positive pole of the gel.

DNA samples can be extracted from hair, blood and skin. Siblings have different DNA fingerprints because everyone has 23 pairs of chromosomes and for each pair one is one of your mother’s chromosomes and the other is your father’s chromosomes. Other than identical twins no other people have exactly the same DNA. DNA fingerprinting is used every day to determine whose parents or siblings are whose, it is used in crime scenes to determine who was at the scene, can be used to determine where a certain inherited gene is inherited from and it can be used to identify a body that is deceased. During electrophoresis an electric current passes through the agarose gel, therefore moving the DNA samples through the gel. The smaller the DNA fragment the faster it moves through the gel. The finished product will look like a series of bands, some will match up and some won’t. The different bands in electrophoresis represent different gene fragments.

Gel electrophoresis is a procedure used in laboratories to separate DNA, as well as RNA and proteins. A gel slab is placed in a buffer-filled box and an electrical field is applied. The negatively charged DNA will migrate towards the positively charged side, where it can then be recorded and further analyzed.

This is now the solution to load onto the argrose gel. Once completed the first stage of the experiment then continue onto the Gel electrophoresis which is before the isolation of your DNA: 1. Make a 2% agarose gel; add water and add TBE buffer 2. Heat the solution to completely dissolve the solution. (No crystals should be present) 3.

Gel electrophoresis is also used in crime scenes when identifying

Linking with Forensic science, I completed investigations which involved fragments of DNA separating. One of which was DNA separation and with 4 samples. Figuration of samples which were similar and related were identified, this was done by using an electrophoresis tray as the fragments separated, and observations were also made in the banding patterns of DNA

Abstract The purpose of this lab was to get a better understanding for the methods that forensic analysis would use in order to determine the identity of a suspect through DNA fingerprinting. In order to identify the culprit out of two possible suspects, DNA fingerprinting was tested by the usage of gel electrophoresis and restriction enzyme. Gel electrophoresis is a technique that is used in order to help separate molecules based on their possible sizes and charges. An electrical currents is applied to the gel in order to separate DNA, RNA, and protein molecules.

In slab gel electrophoresis agarose or polyacrylamide is used. The conducting buffer is contained in the porous gel and the gel is then poured in between glass plates. These plates are separated by spacers. An electric field is applied at the rear after the substance of experimentation is added to the wells at the top. The substance will then move a certain distance towards the positive electrode. This method uses gel unlike the cellulose acetate strips but it still uses a buffer and a electric field to migrate the substances based on their size and charge. Slab gel electrophoresis is usually used in the biological

The marker DNA contained DNA fragments whose base pairs and size were previously known. Thus, when it is separated through gel electrophoresis, the strands visible can be compared to the other DNA strands and the size of the adjacent strands can be estimated. A semi-log graph was utilized to determine the unknown DNA fragment sizes. The distances migrated, and the DNA fragment size of the marker DNA was first plotted. Then, a line of best fit was drawn for reference. The distance the DNA fragments of crime scene DNA, suspect one’s DNA, and suspect two’s DNA had traveled through the agarose gel was calculated. Once those values were known, the points along the line of best fit that were intersected by the x-axis values of the distance traveled by the DNA fragments were the estimated sizes of the separated DNA fragments. Once the sizes were discovered, the data was observed in order to exonerate and implicate a suspect. After observation, suspect one was exonerated as suspect two’s DNA fragments closely resembled and matched up with those in the crime scene

The dye used is ethidium, which is a cation and binds to the negatively charged DNA. It can intercalates between stacked base pairs of DNA. When exposed to ultraviolet light, it fluoresces thus visualizing DNA bands. Lane I is DNA sample prepared by method I with buffer, EcoRI enzyme, and sterile water.

This technique is essential to resolve the PCR products and analyze them. The DNA is determined in the gel by addition of ethidium bromide, which is mutagenic, or non-mutagenic dyes such as GelRed. When these two bound to DNA fluoresce, meaning that they absorbe UV light. Therefore, DNA images are available after gel is exposed to UV light from a UV transilluminator. Negatively charged DNA will move towards the positively charged anode through the agarose gel, while the migration of DNA is dependent of molecular DNA size, agarose concentration, DNA conformation and applied current.

The polymerase chain reaction or PCR for short can be used to create many copies of DNA. This allows the DNA to then be visualized using a dye like ethidium bromide after gel electrophoresis. The process has been refined over the years, however the basic steps are similar.