Extracting DNA from Strawberries Honors
1. Why is the ethanol use in this lab? Explain its importance and the significance of it being “ice cold”? 5 points
The coldness stops the DNA strands from breaking apart. The DNA strands are held together by hydrogen bonds. When you use heat to break the nuclear membrane, the heat can also break the hydrogen bonds. So you add the cold ethanol to keep the DNA strands together, and also DNA is non-soluble in ethanol, so it will precipitate out. (See "Extracting DNA from Strawberries Honors", provided by Ms.Morse, 2/21/12.)
2. Why was the detergent included in the DNA buffer? Molecularly, what purpose did it serve? Cite sources after the answer in APA format. 3 points.
The detergent breaks open the cell & nuclear membranes. This is because the detergent is a hypotonic solution, which would cause cell lysis. (Wilbraham, A. C. (2005). Prentice Hall chemistry. Upper Saddle River, N.J.: Prentice Hall.)
3. Would the DNA be the same in any cell in the human body? Explain. 3 points.
Theoretically, yes. All cells are derived from the zygote. However, there can be somatic mutations that could change the DNA in random cells.
4. If DNA was extracted from human liver tissue would you follow the same procedure as with strawberries? Explain your answer with a molecular emphasis. 5 points, cite sources in APA format after your answer.
Strawberries are an excellent source for extracting DNA because they are easy to pulverize which breaks the cells of the strawberries apart. The homogenate of strawberries is produced through the kinetic energy (heat which can weaken or even destroy intermolecular forces) mechanically breaking down of the cell wall and structure. (Wilbraham, A. C. (2005). Prentice Hall chemistry. Upper Saddle River, N.J.: Prentice Hall.)
5. In research labs the concentration of DNA in a sample is found with a spectrophotometer, explain how this method could indicate DNA...