Osmosis And Diffusion Lab Report
Danna Vitug
September 23, 2014
AP Biology – 2
Mrs. Dahle Lab 1: Diffusion & Osmosis
9/16/14-9/19/14; Jessica Bullock, Andrew Buchholz, Kristamae Masiclat TITLE: Different Ways to Express Diffusion and Osmosis INTRODUCTION:
Diffusion is the spontaneous movement of a substance down its concentration gradient, from a region where it is more concentrated to a region where it is less concentrated. Osmosis is the diffusion of water across a selectively permeable membrane.
The objective of this lab is to observe the different effects of diffusion and osmosis through different molarity solutions. Also, it helps understand the concept of how the separation of two solutions between a selectively permeable membrane could affect the weight …show more content…
Then, take it out and tie off one end of the tubing to form a bag. Put an extra fold at the end, twist, and tie it with string. Rub the end of the other end between fingers until it opens. Put 15 mL of the 15% glucose/1% starch solution in the bag. Use the glucose tape and dip it in the solution. Then, record the color change on the tape and the bag. Tie the other end of the bag with enough space for expansion. Fill a 250-mL beaker with distilled water. Add 4 mL of Lugol’s solution to the beaker and record the color change. Test the solution for glucose. Place the bag into the beaker. Wait 30 minutes to see the change of color in the bag or in the beaker. Finally, record the final color of the bag and beaker. Finally, test the liquid in the bag and beaker for any presence of glucose.
Exercise 1B: First, soak six 30-cm of dialysis tubing in water. Then, take each one out and tie a knot on one end of each piece to make a bag. Pour 25 mL of a different solution (distilled water, 0.2 M sucrose, 0.4 M sucrose, 0.6 M sucrose, 0.8 M sucrose, and 1.0 M sucrose) into separate bags. Tie the other end of the bag, leaving sufficient space for expansion. Record the initial mass for each bag in grams. Then, fill the cups with distilled water. Place each bag in one cup and label each cup with each solution. After 30 minutes, remove the bags from the water. Finally, record each bag …show more content…
Exercise 1C
1.2 GRAPH
1) Molar concentration of sucrose= percent change in mass
Exercise 1D
1) If a potato core is allowed to dehydrate by sitting in the open air, would the water potential of the potato cells decrease or increase?
As it dehydrates, the solutes become more concentrated so the solute potential becomes more negative and it decreases.
2) If a plant cell has a lower water potential than its surrounding environment and if pressure is equal to zero, is the cell hypertonic (in terms of solute concentration) or hypotonic to its environment? Will the cell gain water or lose water? Explain your response.
The surrounding environment is hypotonic, which causes it to gain water. The cell will have less water than the surrounding environment.
3) In Figure 1.5, the beaker is open to the atmosphere. What is the pressure potential(ψp) of the system?
ZERO
4) In Figure 1.5 where is the greatest water potential?
Dialysis bag
5) Water will diffuse out of the bag. Why?
There is higher water potential inside the bag.
6) What is the molar concentration of solutes within the zucchini cells?
About 0.35
September 23, 2014
AP Biology – 2
Mrs. Dahle Lab 1: Diffusion & Osmosis
9/16/14-9/19/14; Jessica Bullock, Andrew Buchholz, Kristamae Masiclat TITLE: Different Ways to Express Diffusion and Osmosis INTRODUCTION:
Diffusion is the spontaneous movement of a substance down its concentration gradient, from a region where it is more concentrated to a region where it is less concentrated. Osmosis is the diffusion of water across a selectively permeable membrane.
The objective of this lab is to observe the different effects of diffusion and osmosis through different molarity solutions. Also, it helps understand the concept of how the separation of two solutions between a selectively permeable membrane could affect the weight …show more content…
Then, take it out and tie off one end of the tubing to form a bag. Put an extra fold at the end, twist, and tie it with string. Rub the end of the other end between fingers until it opens. Put 15 mL of the 15% glucose/1% starch solution in the bag. Use the glucose tape and dip it in the solution. Then, record the color change on the tape and the bag. Tie the other end of the bag with enough space for expansion. Fill a 250-mL beaker with distilled water. Add 4 mL of Lugol’s solution to the beaker and record the color change. Test the solution for glucose. Place the bag into the beaker. Wait 30 minutes to see the change of color in the bag or in the beaker. Finally, record the final color of the bag and beaker. Finally, test the liquid in the bag and beaker for any presence of glucose.
Exercise 1B: First, soak six 30-cm of dialysis tubing in water. Then, take each one out and tie a knot on one end of each piece to make a bag. Pour 25 mL of a different solution (distilled water, 0.2 M sucrose, 0.4 M sucrose, 0.6 M sucrose, 0.8 M sucrose, and 1.0 M sucrose) into separate bags. Tie the other end of the bag, leaving sufficient space for expansion. Record the initial mass for each bag in grams. Then, fill the cups with distilled water. Place each bag in one cup and label each cup with each solution. After 30 minutes, remove the bags from the water. Finally, record each bag …show more content…
Exercise 1C
1.2 GRAPH
1) Molar concentration of sucrose= percent change in mass
Exercise 1D
1) If a potato core is allowed to dehydrate by sitting in the open air, would the water potential of the potato cells decrease or increase?
As it dehydrates, the solutes become more concentrated so the solute potential becomes more negative and it decreases.
2) If a plant cell has a lower water potential than its surrounding environment and if pressure is equal to zero, is the cell hypertonic (in terms of solute concentration) or hypotonic to its environment? Will the cell gain water or lose water? Explain your response.
The surrounding environment is hypotonic, which causes it to gain water. The cell will have less water than the surrounding environment.
3) In Figure 1.5, the beaker is open to the atmosphere. What is the pressure potential(ψp) of the system?
ZERO
4) In Figure 1.5 where is the greatest water potential?
Dialysis bag
5) Water will diffuse out of the bag. Why?
There is higher water potential inside the bag.
6) What is the molar concentration of solutes within the zucchini cells?
About 0.35