Inquiry Question: Your Goal Is to Answer This Question

Inquiry Question: Your goal is to answer this question…

Why are genes important in determining hereditary traits?

Objectives: DNA Extraction

1. DNA is extracted from human cells for a variety of reasons. With a pure sample of DNA you can test a newborn for a genetic disease, analyze forensic evidence, or study a gene involved in cancer. Try this virtual laboratory to perform a cheek swab and extract DNA from human cells.
2. Student should be able to describe DNA structure

Opening:

Access the Video Clip by going to Campbell Middle School, Faculty Tab, Team 7-2, Cabak, and select “Blog” for 3/28/17:

Brain Pop: Asexual Reproduction or use the URL below…

Username: cmseduPassword: spartan

Key Terms:

DNA (structure, synthesis, bases), nucleotide, RNA (ribosome), mutation (deletion, insertion, substitution), asexual, pedigree

Activity:

Access the Virtual Lab by going to Campbell Middle School, Faculty Tab, Team 7-2, Cabak, and select “Blog” for 3/28/17:

Virtual Lab: DNA Extraction

Press “Start Lab”

In this experiment you need to isolate some DNA from a human test subject.

Why, you may ask, do you need human DNA?

• Scientists isolate DNA for a variety of reasons, some of which include:

1. ______testing
2. body identification
3. analysis of forensic evidence

• DNA Extraction is typically the first step in a longer laboratory process.
• DNA ______is an important part of that process because the DNA first needs to be purified away from proteins and other cellular contaminants.

• We need ______, because that’s where the DNA is. Inside almost every cell in our bodies is a nucleus, and inside each ______is about two meters of DNA.

• Cell – nucleus – ______– histone – DNA

• So where do we begin? First we need to collect some cells from our test subject.

• The skin on the inside of our mouths loses ______of cells every day. These are the cells we’re after.

Here are the materials and equipment you will need to purify DNA from cheek cells.

• Warm water bath
• Cenrifuge
• Buccal swab
• micropipettors
• sample tubes
• lysis solution
• concentrated salt solution
• resuspension buffer
• ethanol
• isopropyl alcohol

II. Burst cells open to release DNA

• The end of the swab must be cut off so you will be able to close the tube.
• Using the micropipettor, add some lysis solution to the tube. Lysis is a Greek work that means “to ______”.

• Place the tube into the warm water bath.

• The lysis solution you just added contains two important ingredients: detergent and an enzyme called proteinase K.

• The ______disrupts the cell membrane and nuclear envelope, causing the cells to burst open and release their ______.

• The DNA is still wrapped very tightly around proteins called histones, and the proteinase K cuts apart the histones to free the DNA.

IV. Isolate concentrated DNA

• Use the micropipettor to carefully remove the top liquid (which contains DNA) and place it into a clean tube. The proteins and other cellular debris stay behind.

• Add some isopropyl ______to the tube.

• Inverting the tube several times mixes the isopropyl alcohol into your DNA solution. Because DNA is ______(does not stay dissolved) in isopropyl alcohol, it comes out of solution. You can now see the clumped DNA with your naked eye.

• Place the tube into the centrifuge and click on the lid to close it and turn it on. This time, after the sample spins in the centrifuge, the DNA sinks to the ______of the tube.

• Once the liquid is removed and the DNA is allowed to dry, you can re-dissolve it in the solution of your choice. You can store it in the freezer for many ______, or you can move on to your next experiment. You have just extracted DNA!

Resubmit any incomplete/missing work. Add completed & graded word to your journal.

Update Science Journal Page Numbers: