• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13
  14. 14
    14

The effect of pH on an enzyme - Fungal amylase.

Extracts from this document...

Introduction

THE EFFECT OF pH ON AN ENZYME - FUNGAL AMYLASE. Background information: Enzymes have five important properties: * All enzymes are proteins. * They are specific in their action. * They can be used over again. * They are destroyed if the temperature is too high. * They are destroyed if the pH is too high or too low depending on the enzyme used. Enzymes are substances that act like catalysts i.e they increase the rate of the chemical reaction without themselves being used up in the reaction. Enzymes are all globular proteins i.e their molecules are round in shape. The substance to which the enzyme combines to is known as the substrate. The surface on the enzyme molecule to which the substrate combines is known as the active site. The shape of the active site is complimentary to the shape of the substrate. The enzyme speeds up the process of conversion of substrates into products. Although the enzyme combines with the substrate for a short time, the enzyme and the substrate split apart afterwards releasing the enzyme. Thus the enzyme is not used up in the process and so it can still be used over again. Enzyme + Substrate-Enzyme substrate -Enzyme product - Enzyme+Product complex complex E + S - ES - EP - E + P Starch: Starch is the storage carbohydrate in plants and in animals starch is used as an energy store. Animals obtain their starch from a variety of plant sources. Starch is a polymer of alpha glucose monomers and is a mixture of amylose and amylopectin.The alpha glucose monomers are joined together by 1,4 and 1,6 glycosidic bonds. Amylose is a single unbranched polymer chain of 500 to 2000 glucose subunits with only 1,4 glycosidic bonds. Amylopectin is branched with both 1,4 and 1,6 glycosidic bonds. When fungal amylase acts on starch it results in the formation of mono-, di- or tri- saccharides. ...read more.

Middle

Amount of starch(mls) Amount of amylase(mls) Test for starch Time(seconds) 1 5 5 5 Positive 2400 3 5 5 5 Negative 60 4 5 5 5 Negative 60 5 5 5 5 Negative 60 6 5 5 5 Negative 30 7 5 5 5 Negative 60 9 5 5 5 Positive 2400 2.5mls of Fungal amylase TEST 1 pH Amount of pH(mls) Amount of starch(mls) Amount of amylase(mls) Test for starch Time(seconds) 1 5 5 2.5 Positive 2400 3 5 5 2.5 Negative 150 4 5 5 2.5 Negative 90 5 5 5 2.5 Negative 60 6 5 5 2.5 Negative 30 7 5 5 2.5 Negative 300 9 5 5 2.5 Positive 2400 1mls of Fungal amylase TEST 1 pH Amount of pH(mls) Amount of starch(mls) Amount of amylase(mls) Test for starch Time(seconds) 1 5 5 1 Positive 2400 3 5 5 1 Negative 240 4 5 5 1 Negative 90 5 5 5 1 Negative 90 6 5 5 1 Negative 60 7 5 5 1 Negative 300 9 5 5 1 Positive 2400 Procedure: When I started the experiment I made sure that I had labelled all my pipettes carefully so that I could use them again without mixing them up. Then I placed my test tubes in the test tube rack so that I wouldn't accidently drop any of them. I then measured out 10mls of the buffer solution using the pipette and the pumpette. I also made sure that I measured out the 10mls as accurately as I possibly could without letting any air bubbles into the pipette. Then I transferred the 10mls into the test tube and added 0.5mls of the fungal amylase that were freshly made just before I started the experiment. I also took the same precaution as I did when I measured out the buffer solution but I also made sure that I did not spill any of the amylase on my hands or on the table top. ...read more.

Conclusion

But if I had been given more time then I would have tried adding the starch and the pH before adding the amylase. Then I could compare the results get for this with the results that I already have to see if this would cause any difference. The most important limitation to this was in making an accurate judgement of the final end point of the reaction. After the end of some reaction the iodine appeared to have a dark brown colour and at the end of some it had a light brown colour so the exact end point was hard to judge. When I did the experiment I only started timing after I had completely added my 10mls of starch and this is not very accurate because the enzyme would have started reacting with the starch as soon as the first drop was added. So I can't completely say that the time I got for the experiment is very accurate because some of the starch would have already been converted to maltose even before I started the stop clock. Since there was only a limited amount of time given to me to do the experiment , I only did pH 1,3,4,5,6,7 and 9 but if I had been given more time then I could have tested a wide range of pH eg: pH 4.5, 6.5,8 etc to see exactly at which point the amylase works best. I could have also change the concentration of the starch if I had more time. But overall with the work I have done and by looking at my results I can draw a firm conclusion that my hypothesis is right and that the enzyme does get denatured if the pH is too acidic or too alkaline and the time taken for the reaction to be completed increases. The experiment also shows that there is a certain pH at which enzymes will work but if the pH is too extreme the enzyme gets denatured. But clearly repeating my experiment would further give me more reliable results. 1 ...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

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

    4 star(s)

    Optinum pH of amylase The optinum pH of alpha amylase is pH 7.0 [16], therefore I am using a buffer solution of pH 7.0 to control the pH of solution. Planning Independent variable The concentration of copper sulphate at 0.1%, 0.2%, 0.4%, 0.6%, 0.8% and 1.0%.

  2. Marked by a teacher

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

    4 star(s)

    The rate at which the starch in the agar plate is broken down does increase as the concentration of the enzyme solution is increased. This is due to the fact that as I increase the concentration of the enzyme solution, I increase the number of enzyme molecules in the solution.

  1. Marked by a teacher

    How does the pH affect the activity of amylase

    3 star(s)

    from the colour you started with, use one column for each repeat, 3 in total Results of the time taken for the enzyme to consume the substrate pH level pH 3 pH 4 pH 6 pH 8 pH10 1 2 3 4 Time 5 Minutes 6 7 8 9 10

  2. Marked by a teacher

    Beetroot Practical Write up

    3 star(s)

    The standard deviation shows that the year's results were quite accurate because each spread of data is considerably comparable. Research of ethanol and the effects of this on the cell membranes of beetroot showed that the pH affects proteins that are essential on the cell membrane.

  1. Investigation of the effect of adding different concentrations of NaCl to an enzyme-substrate (amylase-starch) ...

    experiment, as they can store small volumes of solutions and still allow them to be adequately accessible; test tube racks will be used, as they would provide support for the test tubes. Iodine will be used as a measure of whether or not the starch has been broken down or not.

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

    Wash thoroughly with warm water if contact occurs Iodine- Can be toxic and an irritant. Eye protection should be worn. Any spillage onto the skin should be washed away with water. Only small drops should be used. pH Buffer Very low risk.

  1. Investigating the effect of temperature On the action of Amylase on Starch.

    At 10 C there is more energy being provided so there will be traces of activity it will take a while for the Amylase to break down the starch, as the enzyme is still gaining energy. At 20 C the rate of reaction will be faster, as the Amylase is beginning to break down the Starch much faster.

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

    This procedure is much better than observing the intensity of colour by eye, as it is more accurate and gives a numerical value. - Water Bath I have decided to use a water bath as oppose to a Bunsen burner, as there is a smaller fluctuation of temperature.

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