The Effect of Vinegar and Ammonia on the Cell Membrane of a Beet
INTRO
Membranes are simply phospholipid
bilayers and embedded proteins.
Phospholipids are two fatty acids that
are covalently bonded with a glycerol
and a phosphate group. The two
nonpolar fatty acids are hydrophobic
and the phosphate is hydrophilic.
When phospholipids are placed in
water, the phosphate “heads”
gravitate towards the water with the
fatty acid “tails” in between two rows
of phosphates, as seen in the picture.
Proteins are integrated into this web
known as the phospholipid bilayer to
perform various other cellular
functions.
DISCUSSION
Student Names Here!
OUR EXPERIMENT
A Beat, beta vulgaris, contains betacyanin,
a red colored pigment, in its cells. When
the cell membrane breaks, the betacyanin
leaks out of the cell. The goal of our
experiment was to break open the
membrane using vinegar and ammonia. We
hypothesized that vinegar and ammonia
would cause betacyanin to leak because the
pH level of each chemical would cause the
embedded proteins to denature, changing
their shape, and break apart the
membrane.
Chemical
Water
Acetone (40%)
Ethanol (40%)
SDS (10%)
Ammonia (ph 10)
Vinegar (ph 5)
RESULTS
Betacyanin Extracted
.083
.279
.238
.457
.401
.395
*Class average spectrophotometer data
PILOT STUDY
REFERENCES
Hauslein. Cell Membrane. 2008. 1/18/12.
MadSci Network: Cell Biology. Madsci.org. 2/1/12.
Meyer,Ken. Membrane Lecture: Chapter 5. 1/18/12.
Raven, Peter et al.(2008). Biology. 8 ed. page 85-104
Before testing our own chemicals (ammonia and
vinegar), we first tested a few others to establish
a baseline. Among these were water, SDS,
acetone, and ethanol. We learned SDS was the
most effective of the chemicals; it worked by
disrupting the hydrogen bonds that held the
phospholipids together in the bilayer. We also
learned that as the concentration of each
chemical increased, so did the amount of
betacyanin leakage. The data table displays the
highest concentration of each chemical that we
tested.
Our data supports our hypothesis. Vinegar
and ammonia were both able to denature
the proteins of the membrane and extract
betacyanin. One interesting side note of
the ammonia test was that instead of the
dark red pigment result that we normally
obtained, a dark yellow color was
extracted. This happened because
betacyanin is a natural pigment that
contains proteins which were denatured
by the ammonia along with the proteins in
the membrane. Upon denaturation, the
characteristics of the betacyanin proteins
changed, which caused the color to
change from red to yellow.
If we were to further test our hypothesis,
we would test more acidic and basic
chemicals to see if the amount of
betacyanin extracted would increase so as
to become as effective as SDS.
A procedural error occurred in the water
test because theoretically water should
not have broken the membrane to release
any betacyanin. We believe there was
betacyanin on the exterior of the beta
vulgaris core to begin due to the removal
process braking the membranes of
surrounding cells causing betacyanin to
leak.