DNA
DNA is the hereditary material in humans and all living organisms. DNA can bethought of as the blueprint necessary for building all of the cells that make up organisms. DNA is a large molecule whose information is stores as a chemical code. The basic structural unit of DNA is called a nucleotide, which is composed of a deoxyribose sugar molecule, a phosphate group, and a nitrogen base. The nucleoties link together in a series spiraling clockwise around the central axis ( deoxyribose sugar molecule and phosphate group) forming a twisted ladder called a double helix. There are only four types of nitrogenous bases (adenines, thymines, guanines, and cytosines), and the sequence of these bases encodes the information that determines an organism's traits.
Below are the four types of nitrogenous bases, as well as a deoxyribose sugar molecule and a phosphate group.
Labeled DNA Diagram
Conclusion
Adenine and Guanine both belong to a class of compounds called purines and that Cytosine and Thymine belong to a class of compounds called pyrimidines. Both their shape allows them to bond together with hydrogen bonds. Therefore, knowing the sequence of nucleotides of one stand can be used to determine the sequence of the second strand because there are only four base pairs. In addition of the knowledge that Adenine only connect with Thymine, and Guanine only connects with Cytosine. For example, we can determine that if the sequence of a nucleotide was ATTCAG, that second sequence would be TAAGTC.
DNA Gel Electrophoresis/DNA Profiling
DNA profiling is a technique used to identify individuals by the characteristics of their DNA. PCR (Polymerase Chain Reaction) is a method to make multiple copies of DNA from a single copy or a few copies. Scientist use gel electrophoresis whenever they need to sort DNA strands according to length. These methods would be used when there is an unknown source of DNA such as blood at a crime scene. In the Anna crime scene there was B+ blood found. Both Anna and Alex Garcia have B+ blood, therefore, to figure out whose blood was found at the crime scene DNA profiling was used.
"Gel"
After being cut by restriction enzymes, I had to distinguish the DNA fragments from one another by using the method called Gel Electrophoresis which separates the small pieces of DNA from the bigger ones. In this method, DNA is placed into holes at one end that has a negative charge. The "gel" in gel eletrophoresis is used as a filter that sorts the DNA strands by length. Overtime the DNA moves along the gel to the positive end, because DNA has a negative charge thereby pushing it away from the side that has a negative charge and is pulled to the side with a positive charge, much like magnets. After completing this method I used my paper gel (paper below) as my guide to draw in the bands I would see in each lane of the gel.
Whose DNA?
The blood found at Anna's crime scene was B+, which both Anna Garcia and Alex Garcia have. In order to figure whose blood it belongs to, DNA profiling had to be used. After doing so it is now known that the blood found at the crime scene belongs to Anna Garcia.
Conclusion
Both Restriction enzymes and gel eletrophoresis play a role in DNA profiling. Restriction enzymes is the cutting of DNA at specific nucleotide sequences, and gel electrophoresis is the sorting of DNA fragments according to length. However, if DNA is placed starting closed to the positive electrode it would barely move, therefore, it is better to place the DNA into the holes closest to the negative electrode for a more efficient result.
Besides DNA profiling, scientist and researchers may use DNA analysis to find out an individual's relation to another because gel electrophoresis shows the similarities in DNA an individual has with another.
Besides DNA profiling, scientist and researchers may use DNA analysis to find out an individual's relation to another because gel electrophoresis shows the similarities in DNA an individual has with another.