Question

DNA Extraction Worksheet - PreLab

Name Class & Section DNA Extraction Worksheet - PreLab After reading "Exercise 1 DDNA Extraction" in the lab manual, answer the following questions before coming to lab. This worksheet is to be turned in at the beginning of lab. 1. (2pt) Briefly, outline the procedure for isolating DNA from your cheek cells. 2. Do all cells (except mature RBCs and gametes) contain the same DNA? 3. Do all cells use genes in the same way? Explain. 4. DNA sequencing will soon be commonplace. In the future, your doctor may have this done as part of an initial examination. How do you feel about this possibility and what kind of safeguards should be in place?

Answer 1

1. Procedure for isolating DNA from Cheek cells

Collection of Check Cells
Take a small amount of water and swirl it around your mouth without swallowing and collect it in a test tube. Transfer it into appropriate tubes containing the saline solution.

Releasing DNA from inside the cheek cells
Add 25 % solution of SDS containing EDTA in the test tube. This will break the cell membrane and the contents inside the cells come into the aqueous medium. Gently invert the tubes slowly to mix the content properly until complete cell lysis takes place.

Precipitate the DNA
Hold the tube at a slight angle and pour 95% ethanol down the side of the tube. DNA gets precipitated at the interface between ethanol and cheek solution.

Collection of DNA.
With help of clean glass stirring rod slowly collect the DNA by winding it in one direction. Place the collected DNA in another tube containing 95 % ethanol for washing it and keeping it in the final storage tube containing EDTA solution.

2. All cells in our body expect RBC and gametes contain a similar genetic composition. The somatic cells in a fully grown organism start multiplying from a single source cell and hence genetic consistency is maintained.

3. All cells do not use genes in the same way in spite of having the same genetic constitution. Some genes are activated in a particular organ according to the environment it is present. Genes that are activated in the liver cells are suppressed in the heart or muscle cells.

4. Incorporating DNA sequencing as a part of the initial diagnosis will bring about patient-specific approach toward curing the disease. It will help in targeting the species of bacteria or virus infecting the patients at one go. And it can also bring about any mutation associated risks at the same time.