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

Investigating the activity of diastase.

Extracts from this document...

Introduction

Investigating the activity of diastase Enzymes are catalysts and increase the speed of a chemical reaction without themselves undergoing any permanent chemical change. They are neither used up in the reaction nor do they appear as reaction products. They provide an alternate pathway with lower activation energy for the reaction, hence speeding up the reaction. Structure of enzymes Enzymes are made up of amino acids linked by peptide groups into proteins chains, which are then folded into a complex three-dimensional structure held together by a number of different interactions including hydrogen bonding, ionic interactions, van der Waals forces and disulphide bridges. Lock and key theory of enzyme action The folding of the protein chains in enzymes produces a binding site (the active site) which is lined with specific groups which form weak interactions with particular areas in the substrate molecule, holding it in place. Often, the binding of the substrate molecule to the enzyme results in the enzyme changing shape, so specific amino acid chains are brought to the region where the reaction will take place. These amino acids can act as proton donors or acceptors, or can provide the correct conditions for the reaction, either polar or non-polar. ...read more.

Middle

I will use 4cm3 of 2% starch and 1cm3 of a 2% solution of diastase when investigating pH. When investigating substrate concentration I will use a range of concentrations of starch - from 10% to 1% and 1 cm3 of 2% solution of diastase. Method pH - During the investigation I used 4 cm of 5% starch rather than 4cm3 of 2% starch as in my plan and 1cm3 of a 1% solution of diastase rather than 1cm3 of a 2% solution, as I found the activity of the enzyme had increased from when I did my preliminary work to determine which concentrations and volumes I was going to use. I made up one batch of 5% starch (40cm3 of 10% starch to 40 cm3 of distilled water) to use throughout the investigation. I made 10 cm3 of each of the 1% enzymes (0.1g in 10 cm3 of the buffer solution). These volumes of solution were enough to carry out the whole investigation. Concentration of substrate - I used 2 cm3 of 1% enzyme (0.3g of diastase in 30 cm3 of pH 7 buffer solution) and 4 cm3 of each of the starch solutions. These were diluted from 10% starch with buffer solution i.e. ...read more.

Conclusion

The dots in the dimple trays varied in size and as the trays were used repeatedly the dots faded. Also, I only took samples every 30 seconds - increasing the frequency of the samples as the reaction appeared to be reaching its end point but the end point of each individual reaction was only measured to the nearest 15 seconds. The inaccuracy in the end point was probably the greatest source of error in the investigation. Improvements of the investigation I could try to limit the sources of error further by making the end point more exact. This could be done by using colourimetry or light sensors to determine when the iodine reached a specific shade by measuring light passing through the sample. This investigation only covered pH and concentration of substrate and only a limited range of those factors. To improve the reliability of the results I should take more readings at different concentrations of starch and different pHs to confirm the trends suggested in my results. I would specifically look at higher concentrations of starch, to see if the rate continued increasing linearly and to what point and investigate different pHs, especially around the 2 possible optimum pHs to confirm exactly where the optimum pH range was. In addition the investigation could cover other factors such as effect of temperature and effect of varying the concentration of enzyme on the activity of the diastase. ...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

    To investigate the effect of Diastase on Starch

    3 star(s)

    to alter and is almost guaranteed to achieve the best results possible. Apparatus List 5xWater Baths (35oC, 40oC, 45oC, 50oC, 55oC,) 30xTest Tubes, 2x10ml Syringe, 250ml Beaker for Diastase, 250ml Beaker for Starch, 250ml of 1% Diastase, 250ml of 1% Starch, Stop Clock, Safety Glasses, 1xTest Tube Rack, Marker Pen,

  2. An Investigation Into the Effect of Substrate Concentration On the Rate of Enzyme Activity.

    Temperature (oC) 1 / T for each result and median 1 / T 1 2 3 4 5 6 Median 20 0.09 0.08 0.09 0.07 0.08 0.08 0.08 30 0.10 0.09 0.10 0.08 0.10 0.08 0.10 40 0.09 0.10 0.11 0.11 0.11 0.10 0.11 50 0.13 0.14 0.13 0.10 0.11

  1. Investigating the effect of pH on the activity of an enzyme.

    The problems that I faced are: * Due to the difference in some of the equipment and the method from my plan to the equipment and method given on the method sheet confused me slightly as how the experiment was going to be carried out.

  2. What effect does the pH have on the enzyme diastase? What effect does the ...

    Purple Table Two: Time pH of 1 pH of 3 pH of 7 pH of 10 0 Orange Dark yellow Yellow Purple-black 2 min Orange Dark yellow Yellow Purple-black 3 min Orange Dark yellow Light yellow Purple-black 4 min Orange Yellow Light yellow Purple-black 5 min Orange Yellow Light yellow Purple-black 6 min Orange Yellow Light yellow Purple-black 1.

  1. An Experiment to investigate the affect different temperatures have on the rate of an ...

    The method of the experiment is to heat the Starch and Diastase separately for five minutes at the relevant temperate. Once the five minutes are up to two are mixed together and the solution is tested instantly, (time 0).

  2. Enzyme Assay.

    there is enough substrate available to ensure that as soon as the catalytic site of the enzyme is empty (i.e. as soon as the product has left) more substrate is available to bind and undergo reaction. The rate of formation of product now depends on the innate activity of the enzyme itself.

  1. An Investigation into the Effect of Varying pH on Enzyme Activity

    The volumes of the protease, casein (marvel milk is used in the experiment. It is a powdered milk where water can be added to turn it into milk). The volume of the buffer solution will also be kept constant to provide reliable results.

  2. Catalyse Investigation

    the substrate concentration, produces a corresponding increase in the rate of reaction. If there are sufficient substrate molecules to occupy all of the enzymes' active sites, the rate of reaction is unaffected by further increases in substrate concentration as the enzymes are unable to break down the greater quantity of substrate.

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