How Organisms Adapt to Environmental pH Changes

Hypothesis: If acids or bases are added to a buffer tissue, then I predict the pH will not vary as much as in normal tap water, for both bases and acids, because buffers act as pH regulators in living organisms.


Discussion:

1. In the tests with HCl, the pH dropped from 5 to 2 over the course of 30 drops. In the tests with NaOH, the pH rose from 5 to 12 over the course of 30 drops.
2. The total change for the 30 drops of HCl added to the biological materials was about 3-4 shades on the pH paper. This is about the same change for tap water as well, although tap water’s pH started lower than the rest, and went lower than the rest after the 30 drops. The total change for the 30 drops of NaOH added to the biological materials was about 6 shades on the pH paper. This is about the same for tap water as well, although tap water had the largest pH range (5 to 12) of any substance tested with NaOH.
3. For biological materials, there seemed to be less escalation of pH levels. (See previous page for graph.)
4. Biological materials generally tend to resist changes in pH, although they don’t ordinarily do so very well. When acids and bases are added to biological materials, the pH level tended not to fluctuate as much as normal tap water. For example: the potato’s pH level went from 5 to 4 over the course of 30 drops, although the tap water’s pH level went from 5 to 2.
5. The buffer’s pH levels tended not to change much at all when acids and bases were applied to it; very little reaction occurred, for the pH level rose only by 1 and dropped only by a 3.
6. The pH response of the buffer system was more like the biological materials’ response than the tap water’s response because, like the biological materials, the pH level tended not to change as much or as drastically as the tap water.
7. It shows that biological materials have buffers naturally built into them to resist change in pH, because pH levels tended not to change as much in the biological materials as the tap water.
8. Buffers would aid the maintenance of a relatively stable environment within a living cell in a changing external environment. This is because a changing external environment is sure to alter pH levels in living organisms, thus buffers would be needed to aid in the stabilization of the pH level within a living organism.
9. The model suggests that the mechanism required for regulating pH in an organism is buffers. With buffers, regulating the pH level in an organism is made simple.

Conclusion: By performing this experiment, I have discovered that all biological materials contain buffers to aid in the stabilization of that substances pH level. The potato had the least reaction to acidic and basic changes in its environment and next to the tap water, the egg white and gelatin had the greatest reactions because their pH levels increased and decreased the most. Organisms survive and function despite changes in their environment that might cause their pH levels to shift to either the basic or acidic ends of the scale by using buffers. For example, the buffer solution resisted changes in its pH level the greatest because on the acidity of the solution only decreased by 3 on the pH scale after 30 drops of HCl, and on the basic side of the scale, the pH level went up by only 1 after 30 drops of NaOH had been applied to it. The substance that was affected the greatest was the tap water because is has very few buffers, if any at all: after 30 drops of HCl, the acidity dropped by 3 on the pH scale, and after 30 drops of NaOH, the pH level rose by 7 on the basic end of the pH scale. Living organisms do rely on buffers for life.