Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7

My aim is to investigate the breakdown of starch molecules (polysaccharides) into maltose molecules (disaccharides) catalysed by the digestive enzyme amylase. I am trying to find out if the rate of reaction is affected by pH.

Extracts from this essay...

Introduction

AS Biology T1 Individual Project Kevin Isaacs 12B1 22/10/02 Amylase Investigation Aim: My aim is to investigate the breakdown of starch molecules (polysaccharides) into maltose molecules (disaccharides) catalysed by the digestive enzyme amylase. I am trying to find out if the rate of reaction is affected by pH. Hypothesis: I predict that the amylase will be most effective at breaking down starch at a pH of around 7 to 8. As the pH moves further away from this level, either increasing (becoming more alkaline) or decreasing (becoming more acidic) I expect that the rate of reaction will slow down. Eventually, at very low or very high pHs I expect that the enzyme will not catalyse the reaction at all. Amylase is a biological catalyst. It is found in the mouth in saliva produced by the salivary glands and in the duodenum produced by the pancreas. It speeds up the chemical reaction of breaking down starch into sugar (maltose). A catalyst is a substance that speeds up the rate of a chemical reaction. The catalyst changes the mechanism of the reaction lowering its activation energy. This means that the reaction will take place more quickly as less energy is needed to make the substrate(s)

Middle

* Water bath - This will be needed to keep the temperature constant so as to make the experiment more accurate. * Iodine - This is a Universal Indicator to see how much starch is broken down. If there is starch present it will turn a blue-black colour, if not it will remain a light brown colour. 0.05% iodine will be needed. * Starch Solution - This will be broken down by the amylase. 5cm3 of 1% starch solution will be needed. * Pipettes -These will be needed to measure solutions and enzyme accurately.1cm3 and 5cm3 pipettes will be required. * Amylase - An enzyme, which catalyses in the breakdown of starch. 1cm3 of 0.625 % will be needed. * Range of Buffer solutions (pH of 3.0, 5.0, 7.0, 8.0). - These will be needed to change the pH of the starch solution for the investigation. 5cm3 will be needed. * Stopwatch -This will be required to keep track of the time whilst doing the investigation. * Spotting tile -This will be needed to see the colour of the iodine/solution mixture. Method: Firstly, drops of iodine will be spaced out on the cavity tile. Three test tubes containing 5 cm3 of starch solution, 5cm3 of buffer solution of pH 3.0 and 1cm3 of amylase respectively will be placed in a water bath of temperature 37o C and left for 2 minutes.

Conclusion

and Sodium Hydrogen Phosphate (0.2 mol dm -3 ). They are mixed together in different proportions to produce the levels of pH that I am going to use. I have shown how much will be needed of each substance in the table below. pH Na2HPO4 Citric Acid 3.0 20.55 cm3 79.45 cm3 5.0 51.50 48.50 7.0 82.35 17.65 8.0 97.25 2.75 When handling the acid take care as it may cause burns if it comes into contact with the skin. Gloves and protective clothing including gloves should also be worn. If it is swallowed, wash out mouth and give victim a glass of water. Seek medical attention as soon as possible. If the vapour is inhaled move the victim to fresh air to rest. If any of the liquid gets in eyes, flood the eye with gently running tap water for 10 minutes and seek medical attention. If any acid is spilt on the skin or clothes flood the affected area with water and remove contaminated clothing. Should any acid be spilt in the laboratory, wear eye protection and gloves and ventilate area of spill. Cover with mineral absorbent and clear up. Should any of the alkali be spilt in the laboratory, eye protection and gloves should be worn. Lay down mineral absorbent and scoop into a bucket. Treat the absorbent with water and citric acid and then pour down the drain.

The above preview is unformatted text

Found what you're looking for?

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

Not the one? Search for your essay title...
  • Over 180,000 student essays
  • Every subject and level covered
  • Thousands of essays marked by teachers

Related AS and A Level Molecules & Cells

  1. Marked by a teacher

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

    4 star(s)

    This means there is solid concrete evidence on which I can base my analysis and with which I can prove or disprove my hypothesis. In some ways, however, this would be a bad method for conducting the experiment. The optimum temperature of ?-amylase is 37°C, yet the highest temperature at

  2. Catalyse Investigation

    the active site of the enzyme changing its shape; when it's shape has been changed then the starch will no longer fit in the active site and therefore cannot be digested. This is 15 OC above the suggested typical temperature, see Evaluating Evidence for possible reasons why it is higher than expected.

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

    I tried another experiment with just pH 12, and added drops of iodine to it. The pH turned colourless straight away, showing that it was the high pH 12 that was making the iodine colourless, and no other factor. To query about the other levels of pH, I set-up tubes

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

    In this way I can make up the concentration I require accurately without wasting a lot of solution. Making the Concentrations of the Chemicals Variable 1- Temperature In order to take samples of the solution it is essential that I have enough starting solution to carry out the whole experiment.

  1. Enzymes - investigate the affect of amylase concentration on starch breakdown into glucose.

    This is known as the V-max. To explain my predicted graph further I have decided to split it up into sections: - At point 'a', I predict that the rate of reaction will increase slowerr than proportional to the concentration of amylase.

  2. Trypsin. Hypothesis: - I hypothesize that as the temperature increases the rate of enzyme ...

    If temperature is reduced to near or below freezing point, enzymes are inactivated, not denatured. They will regain their catalytic influence when higher temperatures are restored. Hypothesis: - I hypothesize that as the temperature increases the rate of enzyme catalysed reaction increases.

  1. For this investigation I am going to investigate the effect of the concentration of ...

    pH Level This is once again like temperature in the way that every enzyme has an optimum temperature the same as they have an optimum pH. Optimum means the "best" or in this case the best conditions for the enzyme to break down the starch the quickest.

  2. Theeffects of amylase concentration on the breakdown of starch

    However some enzymes are specifically designed to work more efficiently in more extreme pH levels than others. For example, digestive enzymes (enzymes contained in bile eg.proteases) when released into the stomach are able to work more efficiently at the acidic pH levels than other enzymes.

  • Over 180,000 essays
    written by students
  • Annotated by
    experienced teachers
  • Ideas and feedback to write
    your own great essays

Marked by a teacher

This essay has been marked by one of our great teachers. You can read the full teachers notes when you download the essay.

Peer reviewed

This essay has been reviewed by one of our specialist student essay reviewing squad. Read the full review on the essay page.

Peer reviewed

This essay has been reviewed by one of our specialist student essay reviewing squad. Read the full review under the essay preview on this page.