• 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

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

    4 star(s)

    the starch, copper sulphate and iodine solution into a test tube and mix thoroughly, a blue-black colour is formed as iodine solution and starch are mixed together. Then I will add the amylase into the solution, and start the stop clock straight away.

  2. Marked by a teacher

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

    4 star(s)

    However, as there is no other possible method considerable for pH equality in the starch agar, this factor will have to be ignored in the final results, which means the results themselves will not be as fully accurate as was first hoped.

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

    This is why I have chosen to vary temperature, as I believe it will alter the rate of the reaction. However raising the temperature too far will cause the enzyme to become denatured. This means the bonds holding the tertiary structure of the enzyme together will be overcome, and the active site will have altered in shape.

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

    shall stay the same. Obviously the time shall change only as a result of the varying length in rate of reaction Apparatus 9 boiling tubes pH sensor Measuring cylinder 50 ml 1% starch 50ml 1% amylase Iodine solution Pipette Stopwatch Pilot study A pilot study will be carried out to

  1. Catalyse Investigation

    I have also assumed that the result at 12.5% is an anomalous result. The grounds for the assumption are sound (I had left the solution for a few days and I was using the second set of apparatus, which will obviously not be identical to the first)

  2. Theeffects of amylase concentration on the breakdown of starch

    Natural starches are mixtures of amylose (10-20%) and amylopectin (80-90%). It is the amylose in starch that is responsible for the formation of a deep blue/black colour in the presence of iodine. Iodine is not very soluble in water therefore the iodine reagent is made by dissolving iodine in water in the presence of potassium iodide.

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

    Basically, the enzyme acts as a lock which has a unique shape i.e. the active site of which only the correct key can fit in. This key is the substrate. No other substrate can fit into this active site. This is why enzymes are 'specific'; they work only on one type of substrate.

  2. Amylase Investigation

    Starch: production of dextrose, fructose, and special syrups for the baking, confectionery, and soft drink industries Textiles: stone washing of denim (in combination with pumice stones), bio-polishing and softening of cotton and defibrillation of Tencel(r) fabrics, degumming of silk, bleaching, clean up, removal of starch from woven materials.

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