ITS A LAB! On Osmosis...The magical diffusion of water.

Work sheet to go along with our diffusion and osmosis lab

We recently did a lab to learn more about cell membranes.  It was a diffusion and osmosis lab. Diffusion and Osmosis are pretty important, because water and certain solutes get in and out of a cell through these processes. During diffusion and osmosis molecules move from regions of high concentration to regions of lower concentration. We observed this during our lab. We used dialysis tubing as our permeable membrane. We filled a cup with water and then added iodine, which I have now become familiar with from a recent lab on saccharides. We tied off one end of the tubing and filled the tubing with a solution that contained glucose and starch. We then tied off the other end of the bag and placed it in our cup of water and iodine. We left it to sit over night. And then lather, rinse, repeat.<Just Kidding ha ha. When we came back to our cup the next day we found something interesting. The high concentration of glucose passed through our permeable membrane AKA dialysis tubing, into the lower concentration outside of the tubing. We also found that the bag had expanded. This occurred because of osmosis. The water in the cup had diffused into the bag. Obviously, there was a lot going on and passing through and fro. The iodine also got in on the action, the solution in the bag drastically changed color from its nice translucent state to a midnight black. The iodine had diffused from the cup into the bag. Isn't osmosis and diffusion just magical? :)

Cell Membrane Poster! Yay!

Poster that is now hanging in the biology classroom. Woohoo!

In biology we made posters. But not just any posters! Posters of cell membranes! From making this poster and labeling all the different parts, I learned some new stuff about cell membranes. Cell membranes are very interesting and there is a lot of  "stuff" that is actually part of a cell membrane. Perhaps my favorite of all are the phospholipids which make up the phospholipid bilayer. They keep everything inside. They create a barrier between the "insides" of the cell, and the environment outside of the cell. There are two parts to a phospholipid. The head is hydrophilic and the tail is hydrophobic. Cholesterol is another component of the cell membrane. It resides inside of the phospholipid bilayer. Cholesterol helps cells to communicate with each other. Receptor and transport proteins are also something I learned about the cell membrane. Transport proteins transport different things throughout the cell. Those "things" are received at the you guessed it! The Receptor proteins! Glycoproteins were another part of all of this that really popped out to me. The glycoproteins play a role in cell to cell interactions. Glycoproteins are proteins that contain Oligosaccharide chains covalently attached to polypeptide sidechains. That concludes a little bit about my cell membrane poster. Hopefully this will be the first blog post of many on cell membranes.