Diffusion and Osmosis Lab Journal1. APR LabPlasma membranes are composed of many proteins and have a phospholipid bilayer. These proteins form pores and channels, which allow things to pass through the membrane. Cholesterol helps stabilize the membrane while carbohydrate molecules recognize different cells. Moving molecules using active transport requires energy. An example would be riding your bike up a hill.
Passive transport requires no energy from the cell. An example would be coasting down hill on a bike.2. Osmosis LabBefore starting the experiment I measured the egg’s circumference, which was 5.
5 inches. The shell was intact and smooth. The first step of the osmosis lab was to submerge and egg in vinegar for 72 hours. Immediately after placing the egg in the vinegar bubbles formed on the outside of the shell and the egg floated. Over the three few days the shell slowly dissolved.
The dissolving of the shell is an example of passive transport because no force was used to break off the shell. By the end of the 72 hours, the pieces of the shell were floating on top of the vinegar and only the thin membrane was left. The egg had absorbed more fluid and now had a circumference of 6 inches.
The vinegar passing the through the membrane into the egg is an example of diffusion. Next, I put the egg in a cup full of corn syrup, which has a low osmotic pressure. While the egg was in the corn syrup it lost fluid and shriveled.
Going from a high concentration of water to a low one requires energy; this is an example of active transport. I placed the shriveled egg into a cup of water. The water passed through the membrane of the egg and causes it to swell up again. The egg now has a larger concentration of water. This is an example of concentration gradient.
3. Ph.I.L.S LabThe red blood cell swelled up when I placed it into the hypotonic solution. The hypertonic solution caused the red blood cell to shrink because it lost water.
While the red blood cell was in the isotonic solution it did not shrink nor swell. It stayed the same size because the cell did not loose nor gain water. The transmittance value remained 100 while the range was 0-50 and at 10 while the range was 220-240.