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Question

Click on start lab.
Follow the directions and read the information on each of the slides. For some of the slides, you will need to use your mouse to manipulate the virtual lab. For example, when collecting cheek cells, you will have to put the buccal swab into the person's mouth.
Once you have reached the end of the lab, answer the 8 conclusion questions.

Conclusion Questions.
1. Give two reasons why a scientist might want to extract human DNA.
2. Why do you need cells in order to do DNA extraction?
3. Describe how a cell, chromosome, and DNA relate to one another.
4. Why do we use cheek cells to gather DNA, as opposed to other types of cells?
5. What are the 4 steps to purify DNA from a cheek swab?
6. What does “lysis” mean?
7. Why is a tube of water added to the micro-centrifuge along with the sample tube?
8. After using the centrifuge for the first time, where specifically is the DNA in the sample tube?

For 5 extra credit points, you can do an actual DNA extraction in your home.To get the credit, attach a picture of your final product and at least 1 picture of 1 of the steps in the process. Attach these to the drop box along with your 8 conclusion questions from the virtual lab. If the extraction wasn’t successful, you can get the extra credit for attempting it, but we still need at least 2 pictures.

Answer 1

Here are suggested responses to each of the conclusion questions based on general knowledge about DNA extraction:

1. Give two reasons why a scientist might want to extract human DNA.

   • Scientists may want to extract human DNA for medical research, such as understanding genetic diseases, or for forensic purposes, like identifying individuals in criminal investigations.

2. Why do you need cells in order to do DNA extraction?

   • DNA is contained within the cells of an organism, so to extract DNA, you need to start with a source of cells. Without cells, there would be no DNA to extract.

3. Describe how a cell, chromosome, and DNA relate to one another.

   • Cells are the basic units of life that contain chromosomes within their nucleus. Chromosomes are structures made of DNA and proteins that organize and package the DNA. Each chromosome contains many genes, which are segments of DNA that code for specific traits or functions.

4. Why do we use cheek cells to gather DNA, as opposed to other types of cells?

   • Cheek cells are easily accessible and can be collected non-invasively with a buccal swab, making them a convenient source for DNA extraction without the need for more invasive procedures like blood draws.

5. What are the 4 steps to purify DNA from a cheek swab?

   • The four steps generally include:
     1. Lysis: Breaking down the cell membrane to release DNA.
     2. Precipitation: Adding alcohol (like ethanol or isopropanol) to separate the DNA from the solution.
     3. Centrifugation: Spinning the mixture to concentrate the DNA.
     4. Washing: Removing impurities and salts to purify the DNA.

6. What does “lysis” mean?

   • "Lysis" refers to the process of breaking down the cell membrane to release the cellular contents, including DNA, into a solution.

7. Why is a tube of water added to the micro-centrifuge along with the sample tube?

   • The water tube is added to maintain balance in the centrifuge during spinning. This ensures that the forces acting on the centrifuge are evenly distributed, preventing potential damage or imbalance.

8. After using the centrifuge for the first time, where specifically is the DNA in the sample tube?

   • After centrifugation, the DNA typically becomes visible as a pellet at the bottom of the sample tube, while the liquid above (supernatant) contains other cellular materials and impurities.

Feel free to adapt or expand on these answers as necessary! If you're going to conduct the actual DNA extraction at home, make sure to follow safe procedures and use proper materials. Good luck!