Top-Rated Free Essay
Preview

Digestion Self-Design Practical: The Effect of pH on Enzyme Activity

Good Essays
1394 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Digestion Self-Design Practical: The Effect of pH on Enzyme Activity
Digestion Self-design Practical: The effect of pH on enzyme activity

Rationale
Amylase is an enzyme involved in the digestion system which catalyses the breakdown of starch into sugars. It is not only present in human saliva but also in the pancreas, where it hydrolyses dietary starch into disaccharides and trisaccharides which are converted by other enzymes to glucose to supply the body with energy. pH has an effect on the activity of all enzymes, including amylase. As the pH level increases, the enzyme activity increases, up until an optimum pH level where enzyme activity plateaus. For amylase, this optimum pH levels is usually about pH7. The present study investigates this relationship between pH levels and enzyme activity.

Aim
The aim of the present study is to examine the effect of different pH levels on the rate of amylase activity.

Research Question
What is the effect of varying pH levels on the rate of amylase activity?

Hypothesis
The hypothesis of the present study is that increasing pH levels will increase the rate of amylase activity; pH levels at 7 or higher will show a fast rate of amylase activity.

Variables:
Independent Variable: The independent variable was the varied pH levels manipulated by using a buffer solution of different pH levels. The different pH levels were pH0, pH4, pH6, pH8 and pH10

Dependent Variable: The dependent variable is the amylase activity. Amylase activity was measured by recording the concentration of starch in each test tube at 0minutes, 5minutes, 10 minutes and after the weekend. This was done by adding 2 drops of iodine to each test solution at the end of each interval and recording the colour of the solution using a colour chart.

Controlled Variable: A controlled variable was the time of measurements, timed with a timer on a mobile phone. The measurements were taken at 0 minutes, 5 minutes and 10 minutes. This needed to be controlled in order for the rate of enzyme activity to be measured accurately.

Materials/Apparatus
100mL of starch
20mL of buffer pH 0
20mL of buffer pH 4
20mL of buffer pH 6
20mL of buffer pH 8
20mL of buffer pH 10 pipette 20 test tubes
100mL of amylase
Iodine solution measuring cylinder to measure 5mL
Colour Scale
Method
With the measuring cylinder, 5mL of each pH buffer solution was measured (5mL of pH0, 5mL of pH4, 5mL of pH6, 5mL of pH8 and 5mL of pH10) and poured into 5 different test tubes.
Using the measuring cylinder again, 5mL of starch was measured. 5mL of starch was poured into each test tube with each buffer solution.
2 drops of iodine was added to each test solution.
Using the measuring cylinder again, 5mL of amylase for each test solution was measured and, as simultaneously as possible, 5mL of amylase was poured into each test tube.
As soon as amylase was added, the timer was started, and the first colour measurements were taken at 0 minutes.
After 5 minutes on the timer, the colour of each test solution was measured again.
After 10 minutes on the timer, the colour of each test solution was measured again.
Out of interest, after the weekend (approximately 48 hours), the colour of each test solution was measured again.
This method was repeated for 4 trials.

Precautions
Precautions that were taken in order to attain the most accurate results were the control of the time intervals. Safety precautions included washing our hands after the experiment.

Data Collection and Processing

TRIAL 1 - Colour measurements of test solutions

|0 minutes |5 minutes |10 minutes |following weekend (approx. 48hrs) | |pH0 |black |black |black |very dark blue | |pH4 |black |black |black |dark blue | |pH6 |black |black |black |light blue | |pH8 |black |black |light blue |no colour | |pH10 |white |white |white |no colour | |

TRIAL 2 - Colour measurements of test solutions

|0 minutes |5 minutes |10 minutes |following weekend (approx. 48hrs) | |pH0 |black |black |black |very dark blue | |pH4 |black |black |black |dark blue | |pH6 |black |black |black |light blue | |pH8 |black |black |light blue |no colour | |pH10 |white |white |white |no colour | |
TRIAL 3 - Colour measurements of test solutions

|0 minutes |5 minutes |10 minutes |following weekend (approx. 48hrs) | |pH0 |black |black |black |very dark blue | |pH4 |black |black |black |dark blue | |pH6 |black |black |black |light blue | |pH8 |black |black |light blue |no colour | |pH10 |white |white |white |no colour | |
TRIAL 4 - Colour measurements of test solutions

|0 minutes |5 minutes |10 minutes |following weekend (approx. 48hrs) | |pH0 |black |black |black |very dark blue | |pH4 |black |black |black |dark blue | |pH6 |black |black |black |light blue | |pH8 |black |black |light blue |no colour | |pH10 |white |white |white |no colour | |Evaluation and Conclusion
The results show an obvious trend. Every trial had the exact same results. This shows that the experiment was quite well controlled as the process was repeated for 4 trials and the same results were achieved. For pH0, pH4 and pH6, enzyme activity was rather slow as the starch remained fully present in the solution for at least 10 minutes, as the colour did not change from black in all trials. This shows that at lower pH levels, enzyme activity is very slow. However, at pH10, the colour of the solution immediately became white in all trials, demonstrating an extremely rapid rate of amylase activity as starch was broken down immediately. This shows that at a higher pH level, amylase activity is very fast. At pH8, after 10 minutes the solution was light blue, meaning a rather fast amylase activity rate, and after the weekend, the starch had been completely broken down as there was no colour in the solution. This supports the theory that at pH levels of 7, being the optimum pH for amylase, or higher, the rate of activity of amylase would be high. It also supports the research hypothesis, that with increasing pH levels, the rate of amylase activity would increase. In addition, it is evident that the time intervals effected enzyme activity, as after 48 hours, the starch had been broken down, at least slightly, even at pH0.

Sources of Error and Limitations
The fact that all trials achieved the exact same results shows the strength of the method’s accuracy. Having said this, all 4 trials were done at the same time. This arrises a limitation of the study; it was difficult to add the amylase to each test tube exactly simultaneously with just two people as there were 20 test tubes, and therefore the time intervals may have varied slightly. However, this would have been only a few seconds and would probably have not affected the data in a major way, if in any way at all. Even so, in order to address this problem, it may have been more useful to conduct the trials at different time or have some more people in order for it to be possible for the amylase to be poured into the test tubes at the same time. Human error is of course another source of error, especially as the measurements being taken were colours, the perception of which may be subjective to the experimenter’s own interpretation. Hence a colour chart was used in order to achieve the most accurate measurements of colour.

Suggestions for Improvement
A suggestion for improvement would be to either conduct the trials at different times or have more people available to pour the amylase into the test tubes simultaneously. This would allow the amylase to begin activity at exactly the same time in all 5 conditions and would mean that the time intervals would be more accurate. Another suggestion for improvement would be to add another condition level; pH7, as this is the optimum pH level for amylase and would have been conducive to previous research supporting this. It would have also helped to strengthen the support for the research hypothesis of the study. To take this investigation further, one could add other pH levels, possibly some extreme high pH levels, in order to further develop the theory of the effect of pH levels on enzyme activity.

Conclusion
In this study, it has been demonstrated that the effect of pH levels on amylase activity is as follows; as pH levels increase, the rate of amylase activity increases. In addition, pH levels at 7 or higher have been shown to be optimum for the activity of amylase.

You May Also Find These Documents Helpful

  • Satisfactory Essays

    Amylase Trials

    • 306 Words
    • 2 Pages

    4. Based on the information you have learned about the digestive system, describe the optimal pH for the action of pancreatic amylase. Do classroom experimental results seem to support this finding? Why might there be…

    • 306 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Biology Eei Enzymes

    • 6364 Words
    • 26 Pages

    The aim of this EEI was to test the effects of temperature on the activity of the enzyme Amylase. Solutions of starch and amylase were held at selected temperatures by various methods of temperature control. Once the solutions reached and maintained the desired temperature they were combined. Samples at timed intervals were then taken and reacted with a reagent to determine the effect the selected temperatures had on the reaction rate of enzyme and substrate. Results indicated that the enzyme functions efficiently at its optimum temperature (50oC) digesting the starch present and that any sign of enzyme function at 70oC is completely nonexistent. In summary the experiments conducted in the EEI succeeded in demonstrating the effects temperature has enzyme activity and just how vital enzymes are for biological life.…

    • 6364 Words
    • 26 Pages
    Good Essays
  • Good Essays

    Physioex9.0 Ex8

    • 643 Words
    • 3 Pages

    4. Briefly describe the need for controls and give an example used in this activity. __Controls are needed to validate the results of the experiment. One example is testing for sugar using Benedict's test on Amylase The negative control was used to detect if amylase was contaminated with maltose or not.__…

    • 643 Words
    • 3 Pages
    Good Essays
  • Better Essays

    The purpose of this lab was to check the time needed for salivary amylase and phosphorylase to produce a negative result and how different concentrations affected those times. Enzymes are biological catalysts that can cause a specific chemical change in any part of the body (Walsh, 2002). Many of the reactions that take place within a cell would normally take place at temperatures substantially higher than those present inside a cell (Alberts et al., 2010). Because of this, these chemical reactions require the assistance of enzymes to catalyze the reaction and allow it reaction to occur quickly (Alberts et al., 2010). The substrate binds with the active site on the enzyme to form a substrate enzyme complex (Di Giuseppe, 2002). The substrate is then transformed into one or more products, which are released from the active site and the enzyme remains unaltered (Di Giuseppe, 2002).…

    • 2321 Words
    • 9 Pages
    Better Essays
  • Better Essays

    Upon ingesting food into the mouth, salivary glands secrete saliva which contains the digestive enzyme ‘Salivary Amylase’. This has a neutral pH and…

    • 1910 Words
    • 8 Pages
    Better Essays
  • Satisfactory Essays

    Review Sheet 39b

    • 603 Words
    • 3 Pages

    The following questions refer to Activity 1: Assessing Starch Digestion by Salivary Amylase. 1. At what pH did you see the highest activity of salivary amylase?…

    • 603 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    Sc121 Final Exam

    • 394 Words
    • 2 Pages

    20. Salivary amylase, an enzyme in saliva that breaks down starch, has an optimal pH of 6.7- 7.0. Explain why salivary amylase is active in the mouth, but becomes inactive in the stomach. Salivary amylase is an enyme that’s active in the mouth in order to break down starch into glucose it carries it function out in the environment where the PH is 6.7- 7.0 however activity decreases are the PH changes which is the stomach where the environment is more…

    • 394 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    Biology 101 Lab Paper

    • 275 Words
    • 2 Pages

    * The dependent variable is the rate of reaction. The independent variable is pH levels. The controlled variable is temperature in the room and the enzyme concentration.…

    • 275 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    7.0 because that is when the salivary is most effective and it breaks down carbohydrates.…

    • 705 Words
    • 3 Pages
    Good Essays
  • Better Essays

    Introduction: Enzymes are “specialized proteins made by living cells that serve as biological catalysts.” (eScience Labs, LLC, 2013) These enzymes “allow certain industrial processes to be carried out at normal temperatures and pressures, thereby reducing the amount of energy and expensive equipment needed.”(BBC, 2012) Enzymatic activity can be affected by three factors, pH, salt, and temperature. In this project, we will be seeing how acidic fluids will affect the enzymatic reactions. Furthermore, this experiment will answer the following questions: What level of pH there must be in order for the reaction to slow down, or speed up? Are there specific levels of ph levels that speed up enzymes? Seeing that enzymes tend to do great on themselves, my hypothesis is that acid fluids (low pH levels) will actually hinder the enzymatic reaction. My reasoning behind this is that the substrate will take a longer time to mix with the fluid acids, and thus much of the time will be wasted when the enzyme makes contact with the combined substances.…

    • 1338 Words
    • 5 Pages
    Better Essays
  • Good Essays

    In this lab, I will study how digestion of carbohydrates, proteins, and fats occurs. I will define Key Terms that describe what will occur in the experiments; I will conduct an experiment for each Activity and provide all resulting Data as well as answer Questions from each Activity. I will then provide a short Summary for what I learned in each Activity.…

    • 2093 Words
    • 9 Pages
    Good Essays
  • Better Essays

    amylase lab report

    • 1766 Words
    • 8 Pages

    The purpose of this lab experiment is to investigate factors that can affect the porcine pancreatic amylase enzyme activity in different environments such as the temperature, pH and also how being stored in extreme temperatures can affect the activity of the amylase. The activity of the amylase is going to be determined by the presence or absence of starch in the samples over time. There are some hypotheses on the Effects of temperature and pH; as I add the amylase to the starch in different temperatures the reaction’s rate increases in high temperatures; I belive that the amylase will work better. As the environment grows warmer, the amylase is going to become more energetic and more effective. Amylase is affected by environmental pH. I predict that the amylase activity will work best at a pH 7. As the pH changes from this point I predicted that the amylase activity is going to decrease and eventually stop. If I boiled and froze some amylase solution, and try to digest starch with at it at room temperature, I predict the previously-boiled and frozen amylase will not…

    • 1766 Words
    • 8 Pages
    Better Essays
  • Good Essays

    Exercise 8 Physioex 8.0

    • 858 Words
    • 4 Pages

    a. maximum of amylase is at pH 7.0 (tubes 2 & 5, brownish red) and pH 9.0 showed little activity (tubes 6 & 7, green)…

    • 858 Words
    • 4 Pages
    Good Essays
  • Good Essays

    The follow experiment was prepared, conducted and analysed in order to test at which pH level starch will be digested at fastest. The digestive system is a complex network of organs as well as other structures which all work together to supply the body with the necessary nutrients and energy required. If problem occurs along the digestive tract the consequences can be fatal. Therefore it is extremely important to understand your body’s requirements and the way in which it functions, especially when engaging in one of the most crucial and rewarding activities; eating!…

    • 2550 Words
    • 11 Pages
    Good Essays
  • Good Essays

    We found that, in acidic pH environment, the reaction rate of starch being broken down by alpha amylase is less than that of the reaction rate at a neutral and slightly basic pH environment. This finding partially supports our hypothesis. The spectrophotometer readings in our experiment measured the absorbance of 3-amino-5-nitrosalicylic acid, a colored molecule formed after dinitrosalicylic acid (DNSA) has reacted with the products of the enzymatic reaction or the simple sugars. Therefore, the absorbance readings correspond to the concentration of the simple sugars produced by the reaction.…

    • 440 Words
    • 2 Pages
    Good Essays

Related Topics