Osmosis Lab

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Osmosis Lab
March 22, 2013
Amanda L*****

Introduction
Transport into and out of your cells is important because without cellular transport, the cell could not move material into or out of the cell. This would lead to its inability to survive because cells must take in oxygen and food, and expel waste material that could inhibit the cell from performing in the body. A type of cell transport in particular is passive transport. Passive transport is a kind of transport by which ions or molecules move along a concentration gradient, which means movement from an area of higher concentration to an area of lower concentration. Passive transport does not require an output of energy. There are 4 main types of passive transport: simple diffusion, facilitated diffusion, filtration, and osmosis. In this lab, we are particularly looking at osmosis and how it affects plant and animal cells. Osmosis is the diffusion of water molecules across a selectively permeable membrane. In part A of this lab, we submerged the eggs in vinegar overnight, followed by peeling the softened shells from the eggs carefully while trying not to break the membrane the next day. We then recorded any observations we made on the eggs including weight and appearance. Next, we recorded any observations we could make on the carrots and potatoes before we put them into their solution. We then placed the eggs(animal cells), carrots, and potatoes(plant cells) into their solutions and let them stand in their hypotonic and hypertonic solutions overnight followed by observing any changes in weight and appearance the next day. In Part B, we observed an onion cell exposed to distilled water under a microscope, and another onion cell exposed to a saturated salt solution, and drew the two different cells comparing the differences between their exposure to the hypotonic(water) and hypertonic(salt water, corn syrup) solutions. Part A

Purpose
To observe the effects of hypotonic and hypertonic solutions on plant and animal cells. Hypothesis
I predict that the hypotonic solution will cause the plant and animal cells to enlarge due to the difference in concentration on the inside of the cells, and the hypertonic solutions will cause the cells to shrink due to absorption of water molecules in the cells. Materials

* 400mL beakers (2)
* Tap Water
* Eggs (2)
* Vinegar
* Salt water
* Carrots (2)
* Corn syrup
* Potato strips (2)

Procedure
Day 1
1. Submerge the eggs in vinegar in a beaker. (May have to weigh them down) 2. Leave them undisturbed overnight.
Day 2
3. Peel the softened shells from the egg carefully so as not to break the 3membrane. 4. Record any pertinent observations on the egg, carrot and potato strip. 5. Place one egg and carrot in a beaker of water.

6. Place potato strip in a test tube.
7. Place the carrot in a beaker of saturated salt water and use corn syrup for the other egg. 8. Place the second potato strip in a test tube of saturated salt water. 9. Label the beakers and test tube and place in the cupboard overnight. Day 3

10. Record any pertinent observations.

Observations
Plant and Animal Cells in Hypertonic Solution:
| Solution| Appearance/texture Before| Weight before(g)| Appearance/texture After| Weight After(g)| Egg 1 | Corn Syrup| -translucent-yellowish colour-soft | 77.53| -opaque-white/yellow colour-feels firm| 51.17| | | | | | |

Carrot 1| Salt solution| -orange-sturdy| 2.59| -orange-sturdier -appears slightly smaller| 2.36| | | | | | |
Potato 1| Salt solution| -yellowish colour-sturdy| 2.92| -same colour-sturdier | 2.85| | | | | | |

Plant and Animal Cells in Hypotonic Solution(Distilled Water): | Weight Before(g)| Appearance/Texture After | Weight After (g)| Egg 2| 71.82| -opaque-orange colour| 84.10|
Carrot 2| 2.29| -orange colour-not as sturdy| 2.52|
Potato 2 | 2.49|...
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