Internal Assessment Biology: Respiration in Peas

After gathering all of my data together, I divided them in 2 different sections. One table had the temperature values of two different types of peas during morning hours and the second table had the temperature values of the two different type of peas during evening hours. This way it is easier to observe the rise and fall of the temperature values of the two different types of peas on the two different charts, instead of having them all on one chart.

Conclusion

After conducting this experiment I can state that I have noticed a significant rise of temperature in the non-boiled peas and a decline of temperature in the boiled peas. In order to accompany my results with a theory that could explain what is happening to the peas I decided to use my Biology study guide and the internet. The soaked peas are encouraged to germinate since they were soaked in water, given airy conditions and were placed in a flask, which was kept at room temperature (and room temperature is a lot warmer than the natural environment for these peas which is soil). Germination is described as the process in which a seed emerges from a period of dormancy. There are certain conditions which must be met in order for the seed to germinate properly. The most important of them being: Water, oxygen, temperature and light. When the soaked peas finally go through the process of germination, they speed up their rate of respiration. Energy (ATP) is released during respiration. This energy is used by the pea to sprout later on. Out of all this we conclude that the process of germination by which the peas speed up their respiration releases energy, and as we already know there is a lot of heat released simultaneously when the energy is released. This provides a good explanation to why the temperature rises inside the flasks of the non-boiled peas.

In the other flask we had the boiled peas. Now these peas saw a short increase in their temperature, but afterwards the temperature started to decline. First we must consider the fact that these peas were boiled, which means they were killed (they are not alive anymore). The boiled peas go through the process of decomposition. The process of decomposition is the process by which tissues of dead organisms break down into simpler forms of matter. 2 The reason we saw the sufficient increase in the temperature of the flask with boiled peas was not because they were respiring, but because the chemicals are broken down, which breaks their chemical bonds thus releasing energy (heat). By going through all of what I just stated, it seems that I have basic proof of what happened to the peas in the two different flasks.

Evaluation

1.) Problem: The first problem we encountered was putting the same amount of peas in each one of the flasks. This was a problem, because measuring the same mass for both type of peas was hard so eventually we just tried to be as accurate as we could. The problem this might have caused us is that the flask with most peas will release the most energy, and as a result release more heat changing the temperature.

Solution: Next time use a specific size of beaker, fill it completely up (don’t forget to measure the mass of the beaker itself), take the mass of it and subtract the mass of the beaker from it. This way we make it as close as possible to having the equal mass of both types of peas inside of the flasks.

2.) The amount of light that was present in the room during the morning hours and evening hours. Since light can alter the speed at which respiration happens, it means that the closer the flask was to the sun, the more sunlight it was getting, or if some class was watching a movie the blinds were shut meaning that the light supply was stopped. This might have temporarily slowed the speed of respiration in the peas.

Solution: Place the flasks in a room that would have a constant uninterruptable supply of light energy for the peas.

3.) Room temperature is another large factor in our experiment, since the temperature of the room didn’t always stay the same. The temperature changed each time the window was open, letting in fresh air, making it a little bit colder, or a lot of lab devices like Bunsen burners were used and etc… that made the room hotter.

Solution: Again try to find a room inside the school where the peas would stay in the same spot, in the same temperature uninterrupted.

4.) The amount of oxygen present in the room was another factor which wasn’t considered well. The fact that each time the window is opened there is a sufficiently large amount of oxygen entering the room speeding up the respiration of the peas, and when the school is closed during the evening most of the windows are closed resulting in less oxygen being present in the room.

Solution: You may want to again find a special room to do this, and open a window or provide some sort of way for fresh oxygen to enter the room in relatively the same amounts and keep it that way, until your experiment is over.

References:

1 In Cellular Respiration. [Online]. [Cited on 10th May]. Available from world wide web:<URL: http://en.wikipedia.org/wiki/Cellular_respiration>

2 In Decomposition. [Online]. [Cited on 10th May]. Available from world wide web:<URL: http://en.wikipedia.org/wiki/Decomposition>