BIO 111: Electrophoresis and DNA Fingerprinting

BIO 111: Electrophoresis and DNA Fingerprinting Lab 18

CRIME Scene:

1. Make a prediction of who is the criminal and support the decision. The criminal is Princess Dubbah Elix because she is known to like cheese and was seen entering the room earlier that night.

DNA Evidence Evaluation:

1. Fill in the bands on the Gel Electrophoresis chart below.
2. Compare the crime scene DNA to the suspects and indicate on the chart which suspect is guilty of eating the cheese by circling the suspect's DNA who matches the DNA at the crime scene and write the name of that suspect.

Gel Electrophoresis

Questions

1. For each of the following tasks performed in the activity, using complete sentences, describe what is being simulated in the process of electrophoresis.
2. Scissors cutting the DNA into fragments: The scissors cutting the DNA into fragments represents how the restriction enzymes locate certain base pairs and know where to cleave the DNA.
3. Shading the number of base pairs on the gel electrophoresis chart: Shading the number of base pairs on the gel electrophoresis chart represents where the DNA fragments stopped in the gel.
4. For each term below, describe how it relates to DNA Fingerprinting:
5. Gel Electrophoresis: The process of finding DNA fingerprints is through Gel Electrophoresis.
6. Polymerase Chain Reaction: The polymerase chain reaction relates to DNA fingerprinting because it is a process that makes millions of copies of the same DNA strand.
7. Restriction Enzyme: Restriction Enzymes cleave DNA fragments into portions that can go through the gel easer.
8. Explain in detail what moves the different size DNA fragments down the gel? The DNA moves through the gel based on the size. The smallest pieces can travel the furthest because the electron waves can push it through the gel.
9. Who was the “criminal” that ate the Queen’s cheese? Support the answer. The criminal was Ada Nine, the maid. This can be proved because both Ada and the DNA sample share the same bands on the electrophoresis chart.
10. Number the following steps (1-4) in the correct order:
    __4__ Compare the banding patterns of each DNA sample
    __2_ Pipet the DNA fragments into the wells of the gel

Cut the DNA into fragments using Restriction Enzymes 1

__3_ DNA fragments migrate down the gel

6. Describe the function of restriction enzymes. The restriction enzymes chunk the DNA fragments, so they can be sent through the gel.
7. Describe two other uses for gel electrophoresis. Gel electrophoresis can be used in genetics to isolate certain nucleotide pairs for cloning as well as to be used in molecular biology to organize DNA and RNA by size.
8. Explain the process of DNA Fingerprinting.

DNA fingerprinting is used to help forensic scientists identify a suspect by their DNA. A DNA sample is found at a crime scene and then a sample is taken from the suspect. Each sample is cut into chunks by a restriction enzyme and then placed in electrically charged gel. The positive and negative charges located respectfully at the top and bottom of the gel cause the DNA sample to move through the gel and create bands. Everyone has different DNA sequences, which is why it is hard to fake DNA and fake the banding patterns. Each suspects’ DNA banding pattern is compared to the DNA from the crime scene, and from there a suspect is confirmed.