Study Of The Enviroment On The Cell Membrane

Study Of The Enviroment On The Cell Membrane
Dave Lima
SBI OA1
Mr. Swanson
10/4/99
Purpose: To study the effect of environmental changes in the permeability of living beet root cells.
Procedure A: The effect of pH on the cell membrane
Materials & Method
1. Cut a beet root into slices approximately 2mm thick. Use a cork bore to cut out thirty-five (35) slices.
2. Place the discs in a 250 mL beaker and rinse thoroughly in cool running tap water. The red pigment collected comes from the damaged cells and can be used to analyze the chemical nature of the pigment.
3. The pigment in a beet, anthocynanin, should be analyzed before beginning. This can be done simply by first adding a few drops if concentrated acid to a sample if beet juice.
4. The resulting solution can be compared to a second sample made by adding a few drops if concentrates base to another sample of beet juice. Note the colours of each. Given stock solutions of 0.1 mol/L HCl and 0.1 mol/L NaOH, and graduated cylinders, prepare the following solutions in separate test tubes.
a) 10 mL of 0.1 mol/L HCl
b) 10 mL of 0.01 mol/L HCl
c) 10 mL of 0.001 mol/L HCl
d) 10 mL of distilled water
e) 10 mL of 0.001 mol/L NaOH
f) 10 mL of 0.01 mol/L NaOH
g) 10 mL of 0.1 mol/L of NaOH
5. Place five (5) beet root discs in each of the 7 test tubes.
6. Leave them for 15 minutes and then record your observations. Agitate gently and continue to observe them at 15-minute intervals until no further changes occur.
Procedure B: The effects Of An Organic Solvent
Materials & Methods
1. Prepare beet root discs as for Procedure A. The number required will depend on the control you design.
2. Place five (5) of the discs in a test tube containing 10 mL of distilled water and 2 mL of ethanol.
3. Design a control for this investigation.
4. Agitate gently and periodically for 15 minutes and record your observations.
Observations:
Analyzing anthocynanin by adding concentrated acid and base to beet juice
Mixture Observations recorded
Few drops of concentrated acid added to a sample of beet juice -Concentrated acid caused the anthocynanin to turn to a slightly lighter shade of pink.
Few drops of concentrated vase added to a sample of beet juice -Concentrated base caused the anthocynanin to turn a transparent yellow.
Serial Dilution
Intervals 0.1 mol/L 0.01 0.001 Distilled` 0.001 0.01 0.1
HCl mol/L mol/L Water mol/L mol/L mol/L
HCl HCl NaOH NaOH NaOH
15 -lots of -less pigment -a small -very little -a small -barely -a yellow
Minutes pigment lost lost than the amount pigment lost amount any pigment is
-solution is dark 0.1 solution of from the beet of pigment present in
purple in of HCl pigment root pigment lost the
colour lost lost from the solution
from the from the beet root
beet root beet root
30 -slightly -slightly -slightly -slightly -slightly -slightly -slightly
Minutes more more more more more more more
Pigment pigment pigment pigment pigment pigment pigment
lost since lost since lost lost since lost lost lost
the the since the the since since since
observation observations obser- observations the the the
made at made at vations made at observ- observ- observ-
15 minutes 15 minutes made at 15 minutes ations ations ations
15 made at made at made at
minutes 15 15 15
minutes minutes minutes
45 -solution -solution -solution -a darker shade -solution -solution -the
Minutes is dark is pink in is a of pink than is a light is a light mixture is
purple in colour lighter the 0.001 pink pink very
colour throughout shade of solution of through- through- yellow
throughout pink HCl but not out the out the throughout
than that of the mixture, mixture, the actual
the 0.01 0.01 solution similar similar beet have
solution of HCl to that to that turned
of HCl of the of the brown in
0.001 0.001 colour
mol/L mol/L
HCl HCl
The Effects Of An Organic Solvent: Designing A Control
The control our group designed for this investigation was to have one test tube with 10 mL of distilled water 2 mL of ethanol. This way both test tubes would have a total of 12 mL and 5 beet roots each.
Test tube with 12 mL of water Test tube with 10 mL of water and 2 mL of ethanol
-very little pigment lost
-light pink in colour
-beets moved (twirled) when agitated -very little pigment lost
-only a light tint