210 diffusion and osmosis PDF

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Lab report for professor rami alsaber on diffusion and osmosis...

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Anissa Zibo BIO 210 Prof. Alsaber Lab Report: Observing Diffusion and Osmosis in Living and Selective Permeability Introduction: Diffusion is a process that usually can happen in liquids and gases, in which molecules move from a higher concentration gradient to a lower concentration. Osmosis is the process in which water molecules is moved through a selectively permeable plasma membrane through channels called aquaporins. Diffusion and osmosis are important in living organisms in order to keep the maintenance of cells. If a cell allows in too much water then the cell will burst and become damaged, whilst water moving out of the cell at a fast rate will shrink the cell and cause it to dehydrate. Hypotheses Liquid: The dye drops placed in water will diffuse faster if the water is warmer. Surface Area and cell membrane: The smaller agar cube will be more efficient in diffusing NaOH determined by the movement of the pink dye color. Selective permeability: Water will move into areas with less water. Elodea: The elodea leaves in a hypertonic solution will shrink while the hypotonic solution will cause the cells to swell. Materials: For diffusion in a liquid we used a celsius thermometer, 3 15 mL graduated cylinders, a stop watch, hot plate, ice, dye, distilled water at room temperature, distilled ice water and distilled boiling water.

For the second diffusion experiment we used agar blocks, a beaker, spoon, scalpel blade, metric ruler, paper towels and 0.1 M NaOH. For the selective permeability experiment we used a dialysis tube, twine, test tubes, pipettes, benedict's solution, balance distilled water and a 40% maltose solution. For the elodea experiment we used a light microscope along with its slides, elodea leaves, distilled water, saline and NaCl. Experiment/ Procedures: For the first experiment, we had to add 10 mL of cold water to one cylinder, room temperature water to a second cylinder and hot water to a third. Then to each cylinder we added dye to the water and recorded how many seconds it would take for the dye to dissolve entirely. For the second experiment we had to measure the length and calculate the surface area of the agar blocks. Then we soaked the agar blocks in NaOH solution for five minutes and blotted them dry. The next experiment we placed maltose in two dialysis bags and water in the other two dialysis bags. We then inserted one bag of maltose and one bag of water each in different beakers of maltose and water. We ultimately placed one bag of maltose with water and one bag with lactose, and we placed one bag of water with maltose and one bag of water with water. After ten minutes we removed the bags and weighed them in grams in 10 minute intervals. Finally after 25 minutes, we took the contents from the bag, placed them in test tubes and performed the Benedict's test to determine if there was a colored precipitate. Finally we measured the distance that the pink dye moved throughout each block.

For the Final experiment, we placed elodea leaves under a light microscope under water, NaCl and saline and observed the cells. Results: Experiment 1. Solution

Temp. C

Time

Cold

73

210s

Room Temperature

212

150s

Hot

420

85s

Experiment 2. Length

Surface Area

Volume

S/V

Half-Length

Movement

B/A

3

54

27

6

1.5

2mm

2/1.5

1

6

1

2

0.5

1.5mm

1.5/0.5

Experiment 3. Conditions

0min

5min

10min

15min

20min

25min

Water in bag; maltose in beaker

15.15

15.1

14.78

14.44

14.23

14.00

Water in bag; water in beaker

15

15

15

15

15

15

Maltose in bag; water in beaker

12

12.5

12.6

12.9

13

13.9

Maltose In bag; maltose in beaker

14.3

14.3

14.3

14.3

14.3

14.3

Experiment 4. Elodea in Saline

Elodea in NaCl

https://i.ytimg.com/vi/oIY9Z2WGcoA/maxresdefault.jpg https://images.slideplayer.com/16/5102089/slides/slide_14.jpg

Elodea in Water

http://botany.thismia.com/wp-content/uploads/2010/02/plant_cell_normal.jpg \

Discussion and Results: For experiment 1 we realized that the diffusion of the dye within the water worked better when the water was at a higher temperature. This was possible because the dye molecules were able to move easily and organize themselves in a homogenous mixture in a heated environment. For the second experiment we realized that smaller objects with less surface area are more efficient in diffusing the liquid pink color that we saw. The smaller cube was completely saturated in the color while the larger cube had a wide gap of color. For experiment 3, we realized that water would always try to balance itself out on two opposite sides. Those with bags of water on the inside decreased in volume when measured while those with maltose in the bag increased in volume due to water adding itself. For the last experiment we observed elodea leaves and we saw that the chloroplasts would all center themselves along with the rest of the cells to the center in NaCl and a little bit less in saline, in water the cells were very swollen and looked as if they were going to burst. References: YourDictionary. “Hypertonic Solution Examples.” YourDictionary , LoveToKnow, Corp, 8 May 2017, examples.yourdictionary.com/hypertonic-solution-examples.html....