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

How does the concentration of a substrate affect the activity of an enzyme?

Extracts from this document...

Introduction

Planning (a) Introduction: Enzymes are proteins with catalytic properties (due to their powers of specific activation) that work by lowering the amount of initial energy needed for a reaction. They cannot catalyze these reactions until the substrate involved binds to the active site. This occurs because of the arbitrary movement of liquid molecules that causes the substrate and active site to collide. If the concentration of a substrate is increased in a solution with a predetermined enzyme concentration, substrate-active site collisions will take place more recurrently and the rate at which the enzyme is able to catalyze its reaction will increase.* (*The purpose of this lab was to test the validity of this fact using tangible results.) Question: How does the concentration of a substrate (hydrogen peroxide) affect the activity of an enzyme (catalase)? Hypothesis: If catalase is added to hydrogen peroxide samples of varying levels of dilution (1.5%, 1.0%, 0.5%), the solution with the highest substrate concentration will yield the most activity, thus requiring more potassium permanganate in order to neutralize. ...read more.

Middle

Procedure: 1. First, a catalase sample was prepared by combining a potato portion with 3 mL of water in a food processor or blender. This was placed in a cup, then placed in a separate cup full of ice in order to keep the sample cool and reduce denaturing of the enzyme tested. 2. Next, the different substrate samples were prepared. To prepare 1.5% hydrogen peroxide, 10 mL of distilled water was added to 10 mL of 3.0% peroxide in a graduated cylinder. Three individual 5 mL samples were measured from this and set aside, and the excess was discarded in the waste container. To prepare 1.0% hydrogen peroxide, similar steps were taken, only 6.7 mL of 3.0% peroxide was combined with 13.3 mL of water. To prepare 0.5% peroxide, the same steps were taken, only 3.2 mL of 3.0% peroxide was combined with 16.8 mL of water. (For calculations, see Data Processing/Presentation.) 3. Eighteen 2 mL samples of sulfuric acid were measured with a graduated cylinder and set aside in small test tubes, to be used to stop the reactions. ...read more.

Conclusion

most concentrated hydrogen peroxide solution required the highest amount of indicator to titrate, it has been proven that the hypothesis was correct; increased substrate concentration does in fact yield higher enzyme activity. The above data supports this inference because while catalase mixed with 0.5% hydrogen peroxide only required an average of 1.1 mL of potassium permanganate to neutralize; the 1.5% required an average of 5.3 mL, much higher. Evaluation: While the procedures used were successful in that they proved the hypothesis correct and were for the most part clear and consistent, they were far from perfect. For example, the enzyme used was diluted with distilled water, which could have limited its capability to catalyze. The reactions were not all stopped after exactly three minutes; there could have been a few seconds of inconsistency, which would skew the data. Not enough pipettes were used, therefore contamination could be another issue that would skew the data. Nevertheless, the results produced by experimentation were relatively consistent. Perhaps if it was repeated, more attention could be paid to the issue of contamination, more consistent timing could be observed, and the enzyme tested could remain pure. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Biology 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 International Baccalaureate Biology essays

  1. Marked by a teacher

    Effect of substrate concentration on catalase activity (Biology IA)

    3 star(s)

    = Repeated for each concentration of Hydrogen Peroxide Solution E.g. Average time taken for the coloured liquid to rise by 5cm (seconds) when Concentration of Hydrogen Peroxide Solution is at 0.5% Standard Deviation = E.g. Standard Deviation for 0.5% Concentration of Hydrogen Peroxide Solution D.P.

  2. Browning Enzyme

    in the appearance of the discs yet not much could be done. These would lead the results to be larger than expected. When crushing the discs, some discs were thicker than others and this caused inaccuracies as when they were crushed in the crucible, the discs which were thicker, were

  1. Investigating an enzyme-controlled reaction: catalase and hydrogen peroxide concentration

    nearest 0.1 second even though the stopwatch shows the measurements to the nearest 0.01 second. Conclusion -The conclusion is stated and answers the aim -The conclusion has been explained using scientific theory -A comparison is made with a literature value.

  2. Enzyme activity using the enzyme catalase in different plant sources

    It would have been better and more accurate if the mass of the food samples were taken using an electronic balance. When holding the food sample with our hands, either to be cut or to put into the test tubes, this could cause delay in the reaction as we are

  1. Penicillin - its discovery, properties and uses.

    cited current work in Oxford that showed the drug was not toxic, was ' many hundred times as active as the sulphonamides', and was able to overcome bacteria the sulphonamides did not affect. No scientists were named. 'The prospect is certainly an alluring one,' the article said and, quoting The

  2. The Effect of Temperature on the Rate of Activity of the Enzyme Catalase in ...

    the target 40�C temperature data set SA = standard deviation for mean relative rate of enzyme catalase activity for the target 20�C catalase temperature data set SB = standard deviation for mean relative rate of enzyme catalase activity for the target 40�C catalase temperature data set = number of relative

  1. Biology Lan - factors affecting enzyme activity

    DATA COLLECTION AND PROCESSING: Raw Data Table: Factor: Volume of oxygen evolved � 1.0 ml Temperature �0.2�C 1st Trial 2nd Trial 3rd Trial 4th Trial 5th Trial Average 5�C 15 ml 17 ml 14 ml 16 ml 10 ml 14.4 ml 15�C 15 ml 12 ml 21 ml 11 ml 19 ml 15.6 ml 23�C (room temp)

  2. Experimental Question: What effect does substrate concentration have on the rate of enzyme activity?

    The rate of enzyme activity of catalase obtained from beef liver is examined by using hydrogen peroxide as its substrate. The assay system used in this lab consists of collecting gas produce when the catalase enzyme is mixed with H2O2.

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