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

Investigating the effect of pH on the hydrolysis of starch by alpha amylase.

Extracts from this document...

Introduction

Investigating the effect of pH on the hydrolysis of starch by alpha amylase Planning a: Research question: The aim of this experiment is to investigate the effect of pH on the hydrolysis of starch by alpha-amylase. Hypothesis: Starch is broken down by en enzyme, the enzyme amylase. Enzymes are defined as biological catalysts, which speed up a reaction and make it more likely to happen. They are very specific for each reaction they catalyse, which is called enzyme specificity. Every enzyme molecule has an active site into which a substrate molecule fits in perfectly. At the end of each reaction the enzyme is broken down into 2 products, in this case starch is broken down by amylase into maltose. This mechanism is called the lock and key hypothesis. The pH is one of the factors that affect the rate of a reaction. There are other factors like temperature, substrate concentration and enzyme concentration. I will summarise their importance shortly. If there is an increase in temperature the reaction will also increase. The reaction rate will rise up to the temperature where it works best, which is called the optimum temperature. ...read more.

Middle

mixture, and mixed well by shaking. Immediately a sample will be taken and placed into a tile. This will be continued every 30 seconds and for minutes. After 5 minutes samples will be taken only every minute. Supposedly twp tubes will be run at the same time. The process will be continued for twenty minutes if necessary. Meanwhile the experiment has to be started with other tubes, otherwise there will not be enough time. It is important to rinse the pipettes after each experiment. If the different pHs would mix the pH concentration would change it this would severely affect the results. After each experiment the time it took the reaction to end will be noted. The reaction will have stopped when any blue/ black colour disappears, this will signify that the starch has broken down completely. Data processing and presentation: Tube Time it took the reaction to end Rate of reaction 1/sec pH 1 170 0.00588 pH 2 80 0.0125 pH 4 120 0.00833 pH 7 140 0.00714 pH 9 90 0.0111 Data analysis: When referring to graph #2 and checking the results for pH 1 the hypothesis seem to be correct. ...read more.

Conclusion

Conclusion and evaluation: Overall the experiment was conducted as described in the method. But I cannot really accept my hypothesis, because the was nor a constant increase in the reaction rate nor was the reaction working best at the neutral pH of 7. As I said before we did not use a stopwatch to measure the time, instead a normal wall clock. I believe that this did affect the results in some way. We tried to measure the time accurately but sometimes we forgot the time were we had started or during the 30 seconds we were filling tiles with iodine solution instead of paying attention to the time. To improve the results time should measured accurately with a stop watch. In addition enough tiles should be filled with iodine solution. Another factor which probably influenced the result heavily was that the dropping pipettes were either not cleaned properly or not rinsed at all. Also it could be that the reaction rate had stopped before or between the 30 seconds, so it is hard to get the right time. Due to the fact that we got such unexpected results for the pH concentration of 7, we did the experiment for this concentration again, next time to approve or improve the results the whole procedure should be repeated. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour 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 GCSE Patterns of Behaviour essays

  1. Rates of Reaction - The Iodine Clock

    (2). Add to this 2ml of 0.025 Molar Sodium Thiosulphate and 10ml of 1 Molar Sulphuric Acid - All volumes are measured from the prepared biurets. (3). In a separate 250ml conical flask, collect 10ml of 20 volume Hydrogen Peroxide.

  2. Activity of Diastase On Starch

    in next step I carried out the titration. I took the starch diastase complex (having a concentration of glucose in it) in a burette and the quantitative benedict's in which I added 10 grams of sodium carbonate in a titration flask.

  1. Rates of Reaction- Hydrolysis of Urea by Urease

    concentration of hydrogen ions H+ and a low concentration of hydroxide ions OH�, a pH of 7 is neither acidic nor basic and is considered neutral as the concentration of H+ and OH� ions are the same. Basic solutions have a higher concentration of OH� ions than H+ ions and cover a range of pH from 8 to 14.

  2. The effect of enzyme concentration on the rate of amylase and starch reaction.

    -Volume of Solutions. -Amount of iodine. I will change these variables: -Concentration of amylase (already adjusted into neutral PH) Preliminary work Before I did the method I used a spotting tile technique to see how amylase breaks down starch and here are my results: Starch alone Black Mixture straight

  1. The Iodine Clock

    Beyond reasonable doubt the results are enough to provide sufficient evidence that my prediction was correct, even though some of these results could be improved upon; as related to above. When doing the experiment the method was usually well kept to although at time the measuring of the substances could

  2. The Effect of Temperature on the Reaction Between Amylase and Starch

    and with more energy, which caused them to react more efficiently. At low temperatures, the molecules did not collide as frequently and the starch was therefore not broken down as quickly. This is true of any reaction, whether or not it involves catalysts, biological or otherwise.

  1. THE EFFECT OF BILE SALT ON THE ACTION OF THE ENZYME LIPASE

    If this occurs, my results are unreliable as the data collected will be influenced, and affected by the amount of milk or lipids used in each experiment, therefore, disregarding the varying concentration of bile salt. 10ml of milk will be measured out using a �0.05 pipette, for each trial and for each concentration.

  2. Does the Volume of Amylase Affect the Rate of Reaction between Amylase and Starch?

    and on to the photosensitive cells is then measured and is converted into a unit suitable for a final reading (in this case light absorption).

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