Effect of Temperature and pH on Enzymes | Experiment

• Gabriel Soto

[K1]

Introduction:[K2]

Catalysts is a reactant that increases the rate of chemical reactions. The reason is because it lowers the activation energy needed for the reaction to start. Activation energy is the energy that must be added to start a reaction in the first place. A reaction happens because chemical bonds are broken and atoms are rearranged. Some chemical bonds are stronger than others. That’s why some reactions need more activation energy than others. Also, Optimal range is another state of proving results for the experiment. [K3]

Problem: How could certain factors of pH and Temperature could affect enzymes?

Hypothesis:

pH: pH could affect the activity of the enzyme (catalase). Cause if the environment is to acidic or to basic compared to the natural environment of the enzyme, it could denature the enzyme and prevent it from working.

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Temperature: Temperature could affect the activity of the enzyme (catalase). The reason is because if the environment is to hot or to cold the enzyme will have trouble getting accustomed to either temperature. After it will then get denatured and stop functioning.

[K4]Materials: Potato juice, test tubes, test tube rack, hydrogen peroxide, metric ruler, ice bath, boiling water bath, faucet water (room temperature) also known as distilled water, NaOH[K5], HCL, water, 9 test tube holder, 10 mL graduated cylinder, 3 thermometers, timer or watch, pH strips, goggles, apron, mortar and pestle[K6], and gloves.

Problem: How do certain factors such as pH andTemperature affect enzymes?

Procedure: [K7]

Part A: pH

1. Put 5 drops of potato juice in the three test tubes labeled A.
2. Label each test tube A1, A2, and A3.
3. In the first test tube, add 5 drops of distilled water.
4. In the second test tube, add 5 drops of NaOH.
5. In the last test tube, add 5 drops of HCL.
6. Put one drop of each water, NaOH, HCL on a piece of pH paper. Then, record the pH in the table.
7. Add 3 mL of hydrogen peroxide to each test tube.
8. Wait 5 minutes and record the height of oxygen bubbles in each test tube. Record each in the table.

[K8]

Part B: Cold Temperature and Hot Temperature

1. Put potato juice in 3 test tubes labeled B.
2. Label each test tube B1, B2, and B3.
3. Leave the first test tube in the test tube rack.
4. Put the second test tube in the ice bath.
5. Put the last test tube in the hot water.
6. Wait 5 minutes then take them out.
7. Add 3 mL of hydrogen peroxide to each test tube.
8. Record the temperature of the room, the ice bath and the hot water in the table.
9. After 5 minutes measure the height of the oxygen bubble in each test tube. Record your data in the table.

Part C: Room Temperature

1. Put potato juice in 3 test tubes labeled C1, C2, and C3
2. Add the crushed potato to one test tube and an uncrushed potato cube to another test tube.
3. Don’t add any potatoes to the last test tube.
4. Add 3 mL of hydrogen peroxide to each test tube.
5. When the reaction is over, measure the height of the oxygen bubbles in each test tube. Record the data in each test tube in the table.

Observations and Data:

Data:

Enzymes

pH Levels

Observations: What I saw that each of the factors of (pH and temperature) there was one that performed the best. One test tube always had the most oxygen bubbles. It is clear which catalases were denatured and which performed under their normal environment.

pH Table: Here we see the pH of the water, NaOH and HCL. The pH of the water was 6, NaOH was 13 and HCL was 1. Clearly, NaOH is very basic and the HCL is very acidic and the water was slightly acidic, but being closer to neutral. The test tube that produced the most bubbles was the one with the water. It produced 28 mm worth of oxygen bubbles. The test tube with NaOH produced 20 mm and the HCL produced only 10 mm. This test tube with the water produced the most because the catalase performed the best. Also the catalase was performing well in water.

Temperature Table: In the table, it shows the temperature of the conditions of each test tube. The room temperature was 20 degrees Celsius, the Ice Bath was 0 degrees Celsius and the Hot Water was 90 degrees Celsius. The test tube that remained in the Ice bath bucket temperature produced the most oxygen bubbles with .5 cm and coming in close second was the test tube in the room temperature with .4 cm. The test tube placed in Hot Water produced no bubbles. I think this occurred because the catalase is used to performing in temperature outside of their comfort zone, which is closed to room temperature or colder temperature[K9].

Discussion:

I concluded that Catalase execute in significant environments more likely the ones they’re more used to. I also, learned that if you change the environment on a Catalase it won’t execute normally and might even get denatured. I can concluded this because the potato juice in the water made the most oxygen bubbles (.5 cm) to be exact and the potato in room temperature made the second most (.4 cm). My hypothesis was basically that pH and temperature can affect the enzyme because if the environment is different to what it is regularly use to it could have different affect on it. My hypothesis was supported because the “normal environment” which is basically room temperature. My lab partners and I believe we performed as little errors possible but sources of errors could be mislabeling the test tubes, messing up the data, altering the amount of hydrogen peroxide added to each test tube or any other liquid amount altered and/or the time each test tube was left in the environment. What I learned in this lab that we could compare it to a real life situation is not to alter something or someone environments to an extend because it may alter their performs. What we could have done to take this experiment to the next level is choose different vegetables with Catalase enzymes to see if the results are the same within each factor tested with the potato[K10].

[K1] Title should also mention temperature

[K2] You need to introduce the specific reaction we studied in the introduction. Our enzyme was catalase, the substrate is hydrogen peroxide, the products are water and oxygen. All of that needs to be here.

[K3] This doesn’t make any sense.

[K4] These should be restructured to if-then format. See the lab report notes document on blackboard about how to do this.

[K5] ??? We never used NaOH in this lab.

[K6] Or this

[K7] It is possible to follow your methods but this section should be in paragraph form.

[K8] This isn’t at all what we did in this lab. We used water with known pH (2, 7, and 11), added them to the potato juice, then added H2O2 (the substrate) and measured the foam. We never tested the pH and we never used NaOH or HCL in the lab.

[K9] Your results are good. I just still don’t understand where the NaOH and HCL came from.

[K10] This is pretty good but you should have stated which conditions caused catalase to denature.