• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

An investigation considering how pH affects the break down of starch by the enzyme amylase.

Extracts from this document...

Introduction

An investigation considering how pH affects the break down of starch by the enzyme amylase Hypothesis: The optimum pH for the reaction of starch with amylase is pH 7. PH values lower or higher than this value will result in a slower rate of reaction. Amylase works in the range pH 3 to pH 11. Biological Knowledge PH changes affect the structure of an enzyme molecule and therefore affect its ability to bind with its substrate molecules. Changes in pH affect the ionic bonds and hydrogen bonds that hold the enzyme together, which naturally affects the rate of reaction of the enzyme with the substrate. On top if this, the hydrogen ions neutralise the negative charges of the R groups in the active site so that the substrate and the active site do not attract and therefore do not react. The optimum pH for most enzymes is pH7. In the body, amylase works mainly in the small intestines, where the acidity from the stomach has been neutralised by the hydrogencarbonate ions in the pancreatic juices secreted by the pancreas. ...read more.

Middle

It is not important whether a digital or traditional stopclock is used as there will be the same percentage error either way. Method * Measure out 1 cm� amylase solution with calibrated syringe and put in corvette * Add to this 5 drops of pH 4 buffer solution * Measure out 2 cm� starch solution * Start stopclock and leave for 1 minute * Measure out 1 cm� amylase and place in second corvette * Add to this 2 cm� distilled water * Add 3 drops of iodine solution * Shake it well, placing thumb over top * Set colorimeter to test yellow solution and % Transmission * Place second corvette in colorimeter, blank it * Once the first corvette has been left for 1 minute, add 3 drops iodine solution * Shake it well, placing thumb over top * Put in colorimeter, test * Repeat this method for pH 2, 3, 5, 6, and 7, blanking with the second corvette before each reading on the colorimeter is taken * Repeat twice so that there are 3 sets of 6 readings and calculate means ...read more.

Conclusion

I also initially used 8 drops of buffer solution but when I realised this volume resulted in the readings being too close to the end of the scale, I decreased it to 5 drops. When I was blanking the colorimeter before taking each reading, I initially used 3 cm� of distilled water with 3 drops of iodine. It then occurred to me that this was inaccurate, as amylase solution is cloudy. Therefore, I blanked it with 2 cm� water, 1 cm� amylase and 3 drops of iodine. I decided to experiment with pHs within the range pH 2 to pH7, as I discovered that pH 4 is the optimum pH, instead of my predicted pH7. Risk Assessment * Wear goggles to protect eyes from iodine solution * If spilt on clothes or skin, wash with water to prevent harm to the body * Keep iodine bottle away from edge of table to prevent injury from broken glassware Ethical Implications The amylase solution is taken from an animal. The owner of the animal must permit this act. The animal's body must be paid respect when the enzymes are removed so must therefore be treated carefully. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Molecules & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Molecules & Cells essays

  1. Marked by a teacher

    How does the concentration of enzymes affect the breakdown of starch by a-amylase in ...

    4 star(s)

    10 38.2 8 36.5 6 34.7 4 33.1 2 31.0 0 0.0 * = Anomalous results As can be seen from the table, Experiment 1 obtains many anomalous results. This may be due to a very slight error in measurement, as it is very hard to measure out exactly 0.4cm� of enzyme concentration solution, using a pipette and pipette fillers.

  2. Marked by a teacher

    effect of concentration of copper sulphate on the action of amylase to break down ...

    4 star(s)

    Complete and obtain the whole set of results in the shortest time possible, I did it in about 4 hours. Random Concentration of starch solution (5% concentrated) Different concentration of starch solution will affect the rate of reaction. Make the concentration of starch solution as precise as possible.

  1. 'Investigating how temperature affects the rate action of the amylase enzyme on starch.'

    and allow 15 seconds for the mixture to reach the temperature of water (in the beaker). * 9.) After that, I will begin the time and test process. I will time a repeated duration of 15 seconds and test during each interval.

  2. How does pH affect the Denaturation of enzymes Starch and Amylase.

    Fully aware of what pH 12 I timed how long it took for the pH buffer 12 to react with only the iodine drop. I decided it would not be necessary to carry on using pH 12 with amylase added, and use only the timings I got from adding iodine to the buffer.

  1. Amylase Investigation

    Try till about 60-700C to get a good set of results. 11. Collect the data and record the results in a table. After conducting this preliminary test, I realised that there are some changes to make in order to improve the experiment.

  2. Catalyse Investigation

    H2O (CM3) H2O2 % Time (min) Length (CM) No. Of bubbles 10 150 15 5 3 2 20 150 30 5 3 3 30 150 45 5 3 3 40 150 60 5 3 4 50 150 75 5 3 6 Average No.

  1. Investigating the Rate of Reaction of the Enzyme Amylase on starch

    The first is from the formation of the enzyme-substrate complex. After this stage the enzyme-product complex forms, which also requires energy but less so than the enzyme-substrate complex. Finally the enzyme and products move away, and the enzyme can then be used again to convert a starch molecule to maltose.

  2. Starch and diastase with respect to pH

    The enzymes that make up diastase hydrolyse the different glycosidic bonds that hold the glucose residues together in starch. Amyloglucosidase hydrolyses the ?-1,4 and ?-1,6 glycosidic bonds, as a result terminal glucose units are removed at the end of the chain.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work