Thursday, December 18, 2008
My Turn :)
Saturday, December 13, 2008
Mitosis
In this lab we just looked through the microscope at some cells that were reproducing. That week we had learned all about mitosis and how it works so we were a bit excited to see some actual cells. The first thing we looked at were some Ascaris cells; Ascaris is the largest type of parasitic roundworm in the world. Most of the cells that were undergoing mitosis were quite clear and we were mostly able to determine what stage of mitosis they were in. But when we looked at the allium onion root tip, it was very difficult to find cells that were in mitosis though we were able to find a few. The strangest thing we found was that in telophase the animal cells were blended together but the plant cells actually had a division between the two newly formed cells.
An interesting page about mitosis can be found here.
Deoxyribonucleic Acid
We began our experiment by putting split peas and water into a blender and churning them. Eventually we were left with what looked like a milkshake from your worst nightmare, a horrible green goo that looked bad and smelled worse.
After running it through a strainer which got out all the chunky parts, we put some clear hand soap into the thin green liquid that was left. The hand soap, when left for 10 minutes, dissolved the phospholipids and thus destroyed the plasma membrane, allowing the contents of the cell to flow out. After this we added a very small amount of meat tenderizer which contains enzymes that destroy proteins, this is what makes the meat more tender. In this case, The enzymes in the tenderizer destroyed the proteins surrounding the DNA, which allowed the DNA to leak out. We then added to the solution rubbing alcohol equal to the amount of liquid in the glass which floated on top of the solution.
In the end we were left with the bottom of the glass full of dissolved proteins which looked a lot like green mush. In the top of the glass, however, there were long strings of DNA which were difficult to see with, and impossible to see without a flashlight.