Identifying the Impact of Extreme pH Conditions on CO2 Production

Abstract

The objective of this experiment was to see how extreme pH conditions effect CO2 production. The pH values of 1 and 13 were chosen to be tested on two samples of 10g of germinating mung beans. The beans were soaked then rinsed to not destroy the plastic bottle that would be used as a container to measure CO2 production. The pH 13 solution caused a decline in production, while the pH 1 solution remained consistent with the treatment solution of pH 7.

Introduction:

Cellular respiration is a set of reactions which ultimately produce adenosine triphosphate (ATP) and CO2 and H2O as byproducts from glucose. The chemical formula for cellular respiration is: C6H12O6 + 6O2→6CO2 + 6H2O + energy. ATP stores the energy needed to carry out other reactions all over the body. Beginning with glucose, it goes under the first step of cellular respiration called Glycolysis. It’s main function is to break apart glucose and produces four ATP molecules and two pyruvates. Next, the pyruvates are converted to two molecules of acetyl CoA and two CO2. Then, the molecules undergo the Krebs Cycle reaction producing NADH and FADH2. Finally, the electron carriers couple the electron transfer with the transfer of H+ and make a proton gradient. The protons go into ATP Synthase where they are converted to ATP. Under certain environments an organism can make more or less ATP. How acidic or how basic a substance is, is measured in pH. For this experiment different pH environments were tested on beans. A pH of 7 was used as the treatment and the glass beads were used as the negative control. For major emphasize, extreme environments were tested with pH values of 1 and 14. The hypothesis for this experiment is: Extreme pH conditions effect CO2 production. This is relevant to our world because over time organisms have to adapt to new conditions and it’s interesting to see that the adaption can take years.

Methods and Materials:

1. The Pasco CO2 sensors were calibrated.
2. 10g of glass beads were placed into the bottle and measured for CO2 production as a negative control.
3. 10g of germinated beans were placed into the bottle and measured for CO2 production as a treatment.
4. Two sets of 10g of germinated beans were measured out.
5. One set of 10g was soaked in a 25mL solution of pH 1 for 2 minutes.
6. After 2 minutes the germinated beans were rinsed for 30 seconds using D.I. water.
7. The beans were then placed in the bottle and measured for CO2 production for four minutes.
8. The other set of 10g of germinated beans was soaked in a 25mL solution of pH 13 for 2 minutes.
9. After 2 minutes the germinated beans were rinsed for 30 seconds using D.I. water.
10. The beans were then placed in the bottle and measured for CO2 production for four minutes.

The independent variable was the different pH value of the solutions and the dependent variable was the amount of CO2 produced.

The controlled variables were:

• Amount of pH solution used
• Total grams of germinated beans and glass beads
• Time for soak and rinse

The glass beads were selected as a negative control because since they’re not alive, they are not capable of cell respiration. The pH 7 was selected as a treatment because it’s a neutral solution.

Results:

Fig. 1. Negative control. CO2 production inside a bottle for glass beads. Linear regression is slightly negative.

Fig. 2. Treatment. CO2 production inside a bottle for germinating mung beans in a neutral solution of pH 7. Linear regression is positive.

Fig. 3. Most acidic solution. CO2 production in a bottle for germinating mung beans in a pH 1 solution. Linear regression is positive.

Fig. 4. Most basic solution. CO2 production in a bottle for germinating beans in a pH 13 solution. Linear regression is negative.

Discussion:

Based on these results, the hypothesis stating that extreme pH conditions effect CO2 production was not supported. The pH 7 solution, which is neutral, has the same CO2 production as the most acidic solution, pH 1. There was a decline in a CO2 production for the most basic solution, pH 13. The glass beads should have had a CO2 production of zero, however the sensor may be a little off. Bumping the table while measuring could allow for the ups and downs for the pH 13 solution. This experiment shows that plants may be able to survive in extremely acidic environments better than humans which give plants the better fitness in that environment. There was no result indicating a huge CO2 production gain so this might indicate that the CO2 produced right now is the best a plant can do. In conclusion, the only pH solution to change the CO2 production is pH 13 which is very basic and it effects production in a negative way.