Bio Lab 3 Cell Membranes Lab Report

A completed lab report analyzing cell membrane structures and their functions in biological systems.

Eli Simmons
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BioLab3

Cell 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

Distance of
Diffusion *

Rate (mm/min) *
Total
Diameter

Distance of
Diffusion *

Rate (mm/min) *
2
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(mm)
(mm) (mm) (mm)
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.
Diffusion of Potassium Permanganate and Methylene Blue
0
0.2
0.4
0.6
0.8
1
Initial Read 15 Minutes 30 Minutes 45 Minutes
Time Elapsed
Movement Rate
(mm/min)
Potassium Permanganate (Room Temp) Potassium Permanganate (5°C)
Methylene Blue (Room Temp) Methylene Blue (5°C)

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
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Subject
Biology

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