Affect of Temperature and Organic Solvents on Water Movement

Affect of Temperature and Organic Solvents on Water Movement.

Introduction:

The object of this lab was to take core samples from beet roots and explore osmosis (water movement through cell membrane). The root cells can be affected by a number of things; we used temperature and organic solutions. The plasma membrane is a lipid bi-layer made of lipids and phospholipids. There are proteins in the membrane which help import things into and out of a cell. These proteins help the cell with differential permeability, which specifies which molecules are allowed to pass through the membrane. Diffusion is the movement of highly concentrated particles to an area of low concentrated area; these areas are called diffusion pressures. When particles move, for example movement from diffusion, kinetic energy is the energy that is produced from the movement. Cells need water to operate, if cells dry up they usually die, but if cells have too much water, they can burst. Animal cells have a cell membrane, while plants have a cell wall along with a membrane; this makes a plant cell impossible to burst from in taking water and a little more durable than an animal cell. Solutions that have more water than what is inside the cell will tend to move into the cell through diffusion, this solution is called hypotonic. The opposite would be a hypertonic solution which has less water than the cell and sucks water out of a cell to create equilibrium. Protoplasts are plant cells with no cell walls, this exposes the cell membrane. If that plant cell was placed in a solution of sucrose or salt, the cell would shrink because diffusion would force water out of the cell. A regular plant cell would suck in from the cell wall and create Hectian filaments between the membrane and cell wall.(Biology Lab Manual 2007)

In this experiment I expected that a few of the beet cells would produce a solution that had a reasonably low absorbance level of light. With the plant cells in water I expected the cell to get large and press against the cell wall, but with sucrose, the plants should shrink creating the Hectian filaments. With the protoplast cells, the water should cause the cell to burst. The sucrose solution should shrink the cells to a very small size. The blood cells should have the same reaction to water and sucrose as the protoplast cells do.

Materials and Methods: Part I

Beet root, cork borer, razor blade, test tubes, ruler, water baths at 45˚C, 65˚C, 75˚C, and 100˚C, Ice, Distilled water, Acetone, and a Spectrophotometer.

* Label 8 test tubes. Put 10 mL of distillled water into first 6 of the tubes. In #7 put 10 mL acetone, and in the final tube put 10 mL methanol. Place tube 1 in ice bath.

* Get a handsome beet root.

* Use a 1cm cork borer and cut 8 pieces out of the root.

* Using a sharp razor, cut eight, 2.5 cm pieces.

* Rinse cut pieces, then blot with paper towels.

* Put beets in tubes, one per tube.

* Place tubes in indicated temperatures. Tubes 7 and 8 should stay at room temperature.

* Incubate tubes for an hour. Afterwards shake tubes and remove cylinders.

* Pour liquid contents into a cuvette. Read absorbance at 380. Pay attention to demonstration.

* Draw a bar graph of treatment vs. absorption

Part II:

Elodea leaves or plant cells, protoplasts, sheep's blood, 30% sucrose solution, distilled water, microscope, and slides and cover slips.

* Using a pipet, place a drop of protoplasts on a glass slide.

* Cover drop with cover slip. Take notes on observations. Add drops of water from the side. After adding a few drops, take observations.

* Compare plant leaf cells by mashing a piece of the leaf on a slide in a drop of water. Repeat last step and observe.

* Peel off the skin of the Elodea leaf. Place on clean microscope slide in a drop of water.

* Put