BIOL130L Lecture Notes - Lab Report, Plant Cell, Osmosis

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beigesquirrel386

27 Nov 2013

School

University of Waterloo

Department

Biology

Course

BIOL130L

Professor

Dragana Miskovic

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Document Summary

The osmosis and tonicity of plant and animal cells. The purpose of this lab is to demonstrate the movement of water in and out of a cell. Any substances in random motion move from an area of high concentration to lower concentration. In biological systems, the movement of water through the cell membrane is osmosis. There are three types of environments that the cell can be in. This is present when the concentration of solute in the cell cytoplasm and within the cell is the same. Water will have no net movement because the concentrations are equal. This is present when the concentration of the solutes in the cytoplasm is higher than that of the cell. The net movement will be out towards the cytoplasm because there is a higher concentration of water outside the cell than inside. This is present when the concentration of solute is higher inside the cell than in the cytoplasm.

Related Questions

Cell Membranes Lab Report

Diffusion

Compare the following terms: solvent, solute, andsolution.

Go to Lab, Section I, Exercise 1 to explore the factorsinfluencing the rate of diffusion and complete the following:

Predict how molecular mass and temperature may affect theoutcome of this experiment.

Record the data from information in the Lab in the tablebelow.

Time (min)	Diameter (mm)
Time (min)	5Â°C MB	5Â°C PP	23Â°CMB	23Â°C PP
0
15
30
45

Construct a line graph of the data from the table above. Yourgraph should include labeled axes, units, and a legend indicatingwhich treatment is presented. Sign, date and prepare an image ofyour graph and include it with this lab report.

Osmosis

Go to Lab, Section II, Exercise 2 to view a demonstration ofosmosis and answer the following questions:

Describe the net movement of water in osmometer 1.

How is the movement of water molecules related to theconcentration gradient of the solution?

Go to Lab, Section II, Exercise 3 to observe the effect ofsolute concentration on the rate of osmosis. Answer the followingquestions:

Was the net movement of water in bags 1 to 4 into or out of thebags?

Explain the results from bags 4 and 5.

Selective Permeability of Membranes

Go to Lab, Section III, Exercise 4 to learn about theimportance of selectively permeable membranes, then complete thetable and answer the following questions:

	Contents of Beaker
	0 Min	30 Min
Starch
Chloride ion

Which substances diffused through the dialysis membrane?

How does dialysis tubing model the selective permeability of aplasma membrane?

Tonicity

Go to Lab, Section IV, Exercise 5 and 6 to observe plasmolysisin Elodea cells and tonicity in red blood cells. Summarizethe concept of tonicity using blood and Elodea cells asexamples. Your description should incorporate these terms: turgid,plasmolysis, hemolysis, and crenation.

Cells	Isotonic Solution	Hypertonic Solution	Hypotonic Solution
Elodea
RBC

Based on your previous work, reproduce the table below and drawan illustration of a single cell in each box. Include arrows toshow the direction of water flow relative to each cell and dots tosymbolize solutes. Sign, date and prepare an image of your drawingand include it with this lab report.

Cells	Isotonic Solution	Hypertonic Solution	Hypotonic Solution
Elodea
RBC

Summary Questions

Compare diffusion and osmosis. Give an example of each.

2. In which direction will osmosisoccur if a 15% sugar solution is separated from a 25% sugarsolution by a selectively permeable membrane?

3. Why did osmosis, but not diffusionof sucrose molecules, occur across the dialysis membrane containing20% sucrose solution?

4. You are having a party and thecelery is limp. What might you do to make the celery crisp (turgid)again? What will occur in the cells?

5. A small amount of fertilizer(mineral salts) will stimulate plant growth, but over fertilizationcan kill plants? Why?

6. Michael adds sugar to his coffee.Explain what in this drink is the solvent, solute, and solution.

7. You add a cube of sugar to yourdrink. How could you speed up the diffusion of sugar moleculeswithout stirring?

8. How is dynamic equilibriumestablished within a solution?

amberdeer449

A hypertonic solution has a higher level of solutes so the water moves out of the cells to the surroundings

A hypotonic solution has a higher level of solutes so the water moves out of the cells to the surroundings

The salt and water solution in the potato is a hypotonic solution

Osmosis is the movement of large molecules across a membrane which require embedded proteins

The plain water in this experiment is the solvent and the salt is the solute.

Passive transport requires no energy and the molecules move with the concentration gradient or from high concentration to low concentration

Active transport required no energy and the molecules move with the concentration gradient or from high concentration to low concentration.

The water on the inside of the potato with the salt molecules is an isotonic solution the same as the solution on the outside of the potato.

Water will not move by simple diffusion (osmosis) into or out of cells it requires energy or protein transporters

The solution of salt water in the potato has a lower concentration of water molecules so the water on the outside should move into the cells

Dialysis bags or model âcellsâ (A, B, C and D) are placed in beakers containing a 20% sucrose solution. Each model âcellâ contains an unknown concentration of sucrose solution. Every 15 minutes, the model âcellsâ are weighed and the data entered in the table below. Table: Mass of Model âCellsâ Containing Different Concentrations of Sucrose Time (minutes) is 0,15,30,45. âCellâ containing solution A is 11.4, 11.3, 11.2,11.3(mass grams) âCellâ containing solution B is 12.5, 13, 13.5, 14(mass grams) âCellâ containing solution C is 10.8,9.6, 8.2, 7.2(mass grams) âCellâ containing solution D is 10.8, 10.2, 9.5, 9.2(mass grams) what is the Movement of Water, % Sucrose in âCellâ & Tonicity in âCellâ of each cell (A-D)

a) Use the data in the table to determine the movement of water. Choose from âInto the cellâ, âOut of the cellâ or âNo net movement of waterâ Write your answer in the row of the table labeled âMovement of Waterâ.

b) Based on the movement of water, you can determine what the concentration each solution must have been at the beginning of the experiment for each model âcellâ A-D. Choose from 40%, 20%, 15% or 10%. Write your answer in the row of the table labeled â% Sucrose in Cellâ.

c) Determine whether each sucrose solution in the âcellâ is âhypertonicâ, âisotonicâ or âhypotonicâ relative to the solution outside the âcellâ. Write your answer in the row of the table labeled âTonicity in Cellâ. Answer the questions below about Part II of this exercise:

1) A. Explain why was there little or no weight change for the model âcellâ containing solution A?

B. This system is said to be at equilibrium. Explain what equilibrium means in terms of the movement of water across the plasma membrane of a cell?

2) The model âcellâ containing solution B gained weight. Therefore, the water moved _________ the âcellâ. Explain why the water moved as it did in this model system.

3) Model âcellsâ C and D both lost weight. Therefore, the water moved _________ the âcellâ. Explain why the water moved as it did in these systems.

4) A. âCellâ C lost more weight than âcellâ D over the same amount of time (60 min). Therefore, âcellâ C lost water at a slower or faster rate than âcellâ D. (circle one)

B. Explain the cause of the difference in the rate of water loss for âcellâ C and D.

5) Do you see a pattern of how water flows into or out of the cell based on the concentration of solute?

Water always moves from a ______________tonic solution to a ____________tonic solution.

6) In the experiment your group will design, you will be using a piece of potato composed of many living cells. Based upon what you have learned about osmosis and tonicity, predict whether a potato core would gain weight, lose weight or stay about the same weight if you placed it in each of the following solutions: Hypertonic â Isotonic - Hypotonic â

BIOL130L Lecture Notes - Lab Report, Plant Cell, Osmosis

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