BioLab 3 Cell Membranes Lab Report complete solutions correct answers key

Question: #7398

BioLab 3 Cell Membranes Lab Report complete solutions correct answers key

I. Diffusion

Define the following terms

Solvent

Solute

Solution.

Diffusion

Concentration gradient

Dynamic equilibrium

EXERCISE 1 – Factors influencing rate of diffusion

Predict how molecule size and temperature will affect the outcome of this experiment

Record the data from the information in the lab

Double click the chart below. A spreadsheet will open. Enter the data from the table above into the spreadsheet in the areas provided. When you are finished, click into another area of the lab report. The spreadsheet will close automatically. Do not close the spreadsheet with the X in the upper right corner

What effect did temperature have on the rate of diffusion

How did molecule size affect the rate of diffusion

EXERCISE 2 – Osmosis demonstration

EXERCISE 3 – Effect of solute concentration on rate of osmosis

Subtract the beginning mass from the final mass for each of the five bags. Record the difference in the table below

Double click the chart below to open a spreadsheet and enter the results from the table above to complete the graph. When you are finished with your work, click into another area in the lab report to close the spreadsheet (do not use the X in the upper right hand corner

EXERCISE 4 – Differential permeability

EXERCISE 5 – Plasmolysis in Elodea cells

Label which sample is turgid and which is plasmolyzed (Answer 1 in each column). Label the cell wall, central vacuole, plasma membrane, and chloroplasts on each slide. For a more detailed view of the slides below, increase the document size to 150% using the drop-down feature on the toolbar or look under zoom in the view options of the menu bar

EXERCISE 6 – Tonicity in red blood cells

Record your observations for each tube in the table below

Summary Questions

1. Compare diffusion and osmosis. Give an example of each.

2. In which direction will osmosis occur if a 15% sugar solution is separated from a 25% sugar solution by a differentially permeable membrane?

3. Why did osmosis, but not diffusion of sucrose molecules, occur across the dialysis membrane containing 20% sucrose solution?

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

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

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

7. You add a cube of sugar to your drink. How could you speed up the diffusion of sugar molecules without stirring?

8. How is dynamic equilibrium established within a solution?

9. How is an unknown solution tested for the presence of starch?

10. How would an unknown solution be tested for the presence of chloride ions?

Solution: #7406

BioLab 3 Cell Membranes Lab Report Complete Solution

BioLab3Cell Membranes Lab Report I. Diffusion Define the following terms. Solvent Any substance capable of dissolving or dispersing another substance. Solute Any substance dispersed by water. Solution. Taken together, the solvent and the dissolved solute. Diffusion The movement of dissolved molecules from an area of higher concentration to lower concentration. Concentration gradient Is present when there is a difference in the amount of like molecules in two regions. Dynamic equilibrium When the solvent and solute molecules become equally distributed and the gradient comes to exist. EXERCISE 1 – Factors influencing rate of diffusion • Predict how molecule size and temperature will affect the outcome of this experiment. Molecule size will either increase or decrease diffusion based on the temperature. Record the data from the information in the lab. Potassium Permanganate R.T. Methylene Blue R.T. Time (min) Total Diameter (mm) Distance of Diffusion * (mm) Rate (mm/min) * Total Diameter (mm) Distance of Diffusion * (mm) Rate (mm/min) * 0 8mm 0mm 0 mm/min 7mm 0mm 0 mm/min 15 14mm 6mm .43 mm/min 9mm 2mm .13 mm/min 30 18mm 10mm .33 mm/min 10mm 3mm .1 mm/min 45 20mm 12mm .27 mm/min 10mm 3mm .07 mm/min Potassium Permanganate 5 Celsius Methylene Blue 5 Celsius Time (min) Total Diameter (mm) Distance of Diffusion * (mm) Rate (mm/min) * Total Diameter (mm) Distance of Diffusion * (mm) Rate (mm/min) * 0 11mm 0mm 0 mm/min 6mm 0mm 0 mm/min 15 12mm 1mm .07 mm/min 8mm 2mm .13 mm/min 30 13mm 2mm .07 mm/min 9mm 3mm .1 mm/min 45 14mm 3mm .07 mm/min 9mm 3mm .07 mm/min * Distance diffused = diameter of each reading minus initial diameter Rate = distance in mm/elapsed time (min) Double click the chart below. A spreadsheet will open. Enter the data from the table above into the spreadsheet in the areas provided. When you are finished, click into another area of the lab report. The spreadsheet will close automatically. Do not close the spreadsheet with the X in the upper right corner. • What effect did temperature have on the rate of diffusion? It either increased or decreased the rate. • How did molecule size affect the rate of diffusion? At first the molecule was large and then it decreased. • What happens to the rate of diffusion over time? Why? It slows down, due to the temperature. • What can you conclude from this experiment? Temperature has an effect on diffusion. II. Osmosis Define the following terms. Osmosis The movement of water molecules across a differentially permeable me...