Zaw+Thura

Zaw Thura Tun
 * __Effects of Osmosis on an Onion Cell__**


 * Relevance:**

All living things are made of cells. It is known that cells import and export most of its chemicals though osmosis and diffusion. It is also known that if the osmotic pressure of a cell is too high or too low, the cell can swell or shrink, and die. If all the cells of the world were like this, nothing would be able to live. However, there is sometimes a protective layer around the cell which keeps the cell from bursting. In this investigation, the effects of a hypertonic (solution has higher solute concentration than the cell) solution on a cell will be //looked into…// Instead of a hypotonic solution (solution has a lower solute concentration than the cell); since the onion cell is a plant cell and apparently has a strong cell wall to protect it from bursting.


 * Goals:**

To measure the effects and time of what happens to a plant cell (onion cell) when exposed to a hypertonic solution.


 * General Expectations and Models:**


 * Independent Variables:**

-Time (stop watch) -concentration of solution (5% salt solution, 2.5%, 1.25% etc) -Physical disturbances (touch, shake, etc.) -Location on the cell to be monitored (a single point to be looking at) -Color of the cell sample (purple)


 * Dependent Variables:**

-Change in color -Reaction time
 * -**Differences in the size of the cell
 * Materials:**

1 Beaker Light microscope Onion Tweezers Stop Watch 5% salt solution Distilled water Glass slide Pipette Digital Camera Possibly a Laptop


 * Method/Procedure:**


 * 1) Gather MATERIALS!
 * 2) Take a purple onion piece off the onion with the tweezers
 * 3) Put onion sample on glass slide
 * 4) Insert Glass slide into microscope
 * 5) Pour 5% salt solution into a container (beaker)
 * 6) Add 5% salt solution to onion slide using the pipette
 * 7) Begin stop watch
 * 8) Take a picture every __minute__ through microscope with camera to record the gradual changes of the onion cell (as seen in the picture below)




 * __Expectations (Experiment):__**


 * __Results:__**


 * __Discussion:__**


 * //__Appendix I:__//**

(Eg: Without active transport the cell would not be able to excrete waste products) Moving materials across the cell membrane against osmotic pressure that takes up energy for the cell
 * Active Transport:**

(Eg: The Onion cell is made up of cells) Collection of living matter enclosed by a barrier that separates the cell from it’s surroundings; basic unit of all forms of life
 * Cells:**

(Eg: Active transport is done with the cell membrane and protein pumps) Thin, flexible barrier around a cell; regulates what enters and leaves the cell
 * Cell Membrane:**

(Eg: Even the onion is made up of cells, you can see it with the microscope) The idea that all living things are made of cells, and new cells are made from existing cells
 * Cell Theory:**

(Eg: Plant cells do not burst in the confines of it’s cell wall) Strong supporting layer around the cell membrane in plants, algae and some bacteria
 * Cell Wall:**

(Eg: The water has a 5% salt concentration) The mass of solute in a given volume of solution, or mass/volume
 * Concentration:**

(Eg: An easy and energy free way of importing and exporting materials for the cell) Process by which molecules tend to more from an area where they are more concentrated to an area where they are less concentrated
 * Diffusion:**

(Eg: The cell and the solution outside the cell will try to reach equilibrium due to osmotic pressure) When the concentration of a solute is the same throughout the solution
 * Equilibrium:**

(Eg: In a hypertonic solution, the animal cell with burst) When comparing two solutions, the solution with the greater concentration of solutes
 * Hypertonic:**

(Eg: In a hypotonic solution, the animal cell with shrink) When comparing two solutions, the solution with the lesser concentration of solutes
 * Hypotonic**

(Eg; In an Isotonic solution, water is gained nor lost through the cell) When the concentration of two solutions is the same
 * Isotonic:**

(Eg: Lipid Bi-layer make up the cell membrane of the cell) Double-layered sheet that forms the core of nearly all cell membranes
 * Lipid Bi-layer:**

(Eg: Some nutrients are imported into the cell by means of Osmosis) Diffusion of water through a selectively permeable membrane
 * Osmosis:**

(Eg: Active transport exports materials against the Osmotic Pressure) The pressure created by osmosis outside the cell by a different concentration of solute
 * Osmotic Pressure:**

(Eg: The onion cell’s Vacuole must have lost it’s water) Cell organelle that stores materials such as water, salts, proteins, and carbohydrates
 * Vacuole:**