Cell Respiration Lab

Exercise 1A

Purpose 

The purpose of the lab is to see cellular respiration happen before our very own eyes. From our power point, we know that within cellular respiration, CO2 is released and O2 is used. So, in this lab, we should see an increase of CO2 and a decrease of O2 from the peas and mung beans. In addition to the germinated, we will test non germinated peas and cold peas. 

Introduction

Cellular respiration is the process in which plants use and release chemical energy of organic molecules that is stored in glucose. Energy that is inside of glucose is used to produce ATP which supplies energy needs of the cell. If it is has a suitable amount of oxygen present, glucose is oxidized and releases energy. The breakdown of glucose to carbon dioxide and water is performed with two requires steps; glycolysis and aerobic respiration. 

Equation For Cellular Respiration: C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy

Methods 

This lab was really fun because we got to play with fun gadgets this time. So the first thing we did was set up the lab on the Lab Quest, plugged in the CO2 and O2 sensors, and placed the peas into the container.

It's a shame that the electronic thermometer didnt work for our lab. Instead, we did it with an actual thermometer.

The thermometer reads 22 degrees Celsius 

Once we finally go everything into place, we started the lab and let it run for 10 minutes.

Here's a picture of Judd and Kenny analyzing the graphs!

After collecting the data from the Lab Quest we repeated the steps again except with cold peas and then non germinated peas. This picture shows Judd removing the already cold peas to put them inside the container. 

Charts and Graphs

By using two different species of peas separately, we found that the type of pea used does not affect the rate of cellular respiration.

As the peas began cellular respiration within the sealed container, the concentration of carbon dioxide gradually increased at a fixed rate. This information that we gathered is sound because carbon dioxide is one of the main products in cellular respiration, similar to the way humans exhale.

Because the container only has a limited supply of oxygen, it makes sense that the oxygen should gradually decrease in concentration as the time of the experiment increases.

Although this graph can be a bit wacky, the line of best fit still supports the other findings within this exercise.

Similar to the previous image, a line of best fit is oftentimes essential for seeing correlations within a particluar exercise.

Here is a graph noting all the experiments conducted and results gathered.Similarities can be drawn from the behavior of oxygen and carbon dioxide ammounts over time.

Based off the information gathered in this chart, we know that the temperature of the environment does not affect how fast an organism produces ATP.

Noting the temperature of the water was important for determining how particle movement affects the rate of cellular respiration.

Discussion 

Perhaps a common misconception is that since the germinating seed is a plant and an autotroph, then it must make its own food through photosynthesis, and we should see the opposite of what the graph is showing: A rise in oxygen and a decrease in carbon dioxide. Instead, the opposite is depicted. Why is that? In the wild, seeds are generally planted underground where there is no sunlight. In order to break through the soil and begin photosynthesis, the plant must attain energy through some other means besides the sun. In all plants, this energy source is the seed itself. As soon as a seed germinates, it begins to feed off the energy stored in the seed, which is in the form of a mix of macromolecules. In order to break down these macromolecules, the seed must engage in conventional cellular respiration. This is why oxygen levels decrease and carbon dioxide levels increase.

 

 

The seeds we used are no different from this germinating Quercus rubra (northern red oak) acorn. The young plant feeds off the acorn until it sprouts and grows a leaf. As soon as a leaf grows, the products of photosynthesis takes over as the plant's main energy source.

 

While our results showed that cellular respiration is independent of temperature, this is actually false. Cellular respiration is dependent on proteins, which can denature if temperatures are not right. This error is most likely due to the short amount of time the seeds were exposed to cold temperatures. Also, it is very likely the seeds warmed toward the end of the 10 minute test as well. The non-germinated seeds did not engage in any significant cellular respiration, as they are in a period of dormancy. Having seeds that can stay dormant for long periods of time are advantageous to plant species reproduction, as there will be a higher chance that the seed will end up in a favorable environment given enough time.

 

Conclusion

From the results of the lab, it is shown that respiration rate is affected by temperature; colder temperatures result in a slower respiration rate while warmer temperatures allow for a faster respiration rate. The Co2 sensor provided the information that germinated peas gave off more Co2 than the non germinated peas. Through the oxygen sensor we could tell that the germinated peas consumed more oxygen than the non germinated peas.

Resources

https://www.youtube.com/watch?v=ZK4LjURtaDw

Enzyme Catalyst Lab

Enzyme Catalyzed Reactions (Including Base Line)

 

Purpose

 

In this first part of the lab, we will determine how excessive pH effects the productivity of an enzyme. Some enzymes work well at higher pH's, while others are more adapted to lower ones. Regardless, every enzyme has an optimum and preferred pH range to work in. By moving an enzyme outside its comfort zone, we will observe the result by noting the change in the rate of the metabolic reactions taking place at the same time. Changing the pH will denature the protein

Introduction

This lab will focus on enzymes and their role in accelerating metabolic reactions by reducing the amount of activation energy required to start a given reaction. Enzymes are simply proteins produced by cells and are catalysts. It is important to understand that catalysts will always assist the reaction without being used up in the process. Therefore, enzymes within our body will continue to operate efficiently unless they encounter an adverse conditions, such as an acidic solution or extreme temperatures. Finally, each type of enzyme is specific to a particular substrate, like sucrase working primarily with the substrate sucrose. In order for our body to break down a myriad of food items, we need a large quantity enzymes to bind with as many substrate molecules as possible so that reactions can be fast and effective.

 

 

Methods

 

                       

For the Base Line Lab we added 10 mL of H2O2, then 1mL of water, and 10mL of H2SO4. Lastly, we added KMnO4 into the 5 mL solutions which we added little by little and mixed in between the drops until the solution turned a bright pink

        

Similar to be base line lab, we added 10 mL and (instead of water) we added 1 mL of catalase extract. At different time intervals, while mixing at the same time , we added 10 mL of H2SO4 into the beaker.

 

Data & Graphs

 

This table shows the results of our enzymatic reaction. As the time increased, the amount of KMno4 decreased while the amount of h2o2 increased. 

 

This graph is taken from part e of the data table. As the independent variable, time, is increased, the amount of H2O2 is also used up. This graph shows an increase of hydrogen peroxide used up from 10 to 30 seconds, then a dramatic decrease, and then a more stable increase until 180 seconds. 

 

Discussion

 

For the most part, our results in this lab were fairly close to what is to be expected, with only one major outlier due to experimental error. The summary of our results can be explained by this sentence: The longer the hydrogen peroxide is exposed to the enzyme catalase, the more of it is broken down to water and oxygen gas. The base line titration had the highest amount of KMnO4 used because it had the highest amount of hydrogen peroxide, as almost none of it was decomposed (the table shows the amount of hydrogen peroxide used, not the amount of KMnO4 consumed).  As soon as we added the sulfuric acid which significantly lowered the pH, the enzymes (as a globular protein) were denatured and the reaction slowed down significantly. From this conclusion, it can be hypothesized that changing other factors, such as temperature, would also promote or inhibit the reaction rate, because proteins can denature when exposed to temperature extremes. By looking at the graph, it is easy to tell there is a serious problem with the 60 second reaction. It does not follow the generally increasing slope of all the other points. One possible explanation would be that water was accidently mixed with the hydrogen peroxide as they are both clear liquids. This would significantly dilute the hydrogen peroxide in the solution to a point where KMn04 titration would take place rapidly and with little KMnO4. Overall however, the longer the reaction rate the greater the amount of hydrogen peroxide converted and the less amount of titrate used.

 

Conclusion

This lab shows how enzyme catalase increase the rate at which h202, hydrogen peroxide, decomposes.When enzyme catalase is added to h202, the catalase is denatured and oxygen is released. Enzyme catalyzed reactions  are affected by the environmental factors and changes such as temperature, pH levels, substrate concentrations, and enzyme concentrations.When we added sulfuric acid, the catalase wasn’t able to break down the hydrogen peroxide due to the change in environment, the ph change, which denatured the enzyme.

 

References

 

http://www.rcsb.org/pdb/101/motm.do?momID=57

http://elmhurst.edu/~chm/vchembook/568denaturation.html

 

 

Uncatalyzed Reactions

 

Purpose

 

Lowering the activation energy of a reaction will reduce the change in free energy when the reaction takes place, and allow the transformation of reactants into products to occur faster and more often. To see just how essential enzymes are to living organisms, we will note what happens when a reaction takes place without assistance from enzymes.

 

Introduction

 

Reactions can take place without enzymes-it just takes a lot more time and energy to get the reaction going. Hydrogen peroxide naturally breaks down into oxygen gas and water over time, as the reaction is spontaneous. The change in free energy is negative. HAVE KENNY ADD MORE TO THIS

 

Methods

 

 

This picture above shows the bubbling of H2O2 when catalase was added. This bubbling represents the O2 gas being released while the H2O2 

 

 

 

Data & Graphs

 

 

 

 

 

Discussion

The results of this lab indicate that the breakdown of hydrogen peroxide to water and oxygen will take place even without a catalyzer. What this proves is that the breakdown of hydrogen peroxide is spontaneous: the reaction releases energy, or is exergonic. In this case, given enough time, hydrogen peroxide will decompose on its own. The activation energy for this reaction, which was significantly reduced by adding catalase, is overcome in this instance by some other means. It is quite possible that the activation energy for this lab came from the atmosphere, as hydrogen peroxide does not decompose this quickly when placed in a sealed container. Nonetheless, this experiment showed that spontaneous reactions can and do occur even without a catalyst.

 

Conclusion

 

 

 

References

http://infohost.nmt.edu/~jaltig/HydrogenPeroxide.pdf