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

The Effect of substrate concentration on the enzyme catalase

Extracts from this document...

Introduction

The Effect of substrate concentration on the enzyme catalase Aim This is an experiment to see how the concentration of the substrate affects the rate of reaction with an enzyme. In this instance, the substrate is hydrogen peroxide and the enzyme is catalase. Background Information Enzymes are commonly known as biological catalysts. A biological catalyst is a molecule that speeds up a chemical reaction, remaining unchanged at the end of the process. Almost all metabolic reactions that occur in living organisms are catalysed by enzymes. Without enzymes, incredibly simple processes that we take for granted would be unable to subsist. Enzymes are globular proteins that are coiled into a precise three-dimensional shape, with hydrophilic R-groups on the outside of the molecules ensuring that they are soluble. Catalase, the enzyme I will be using in this experiment, is found in food such as potato, liver and celery. It is used for removing Hydrogen Peroxide from the cells, which is the poisonous by-product of metabolism. Catalase speeds up the decomposition of Hydrogen Peroxide into water and oxygen. The equations below show this: CATALASE Hydrogen Peroxide Water & Oxygen CATALASE 2H2O2 2H2O + O2 The way enzymes work can be explained by the lock and key theory. Like all enzymes, catalase has an active site. The active site of an enzyme is an area to which another molecule, substrate, can bind. It has a lock and key structure because the active site's shape allows the substrate to fit perfectly. ...read more.

Middle

I am choosing to record the amount of gas given off every ten seconds as it will enable me to collect a large set of results making the experiment more reliable and it means I will be able to compare reaction rate at the beginning and end of the reaction. As my aim is to investigate how the concentration of substrate affects the rate of reaction I needed to choose the different concentrations of hydrogen peroxide that I would test. I carried out my preliminary experiment at different concentrations and have decided to use five concentrations of hydrogen peroxide. This will give me a wide range of results. I will use concentrations of 100%, 80%, 60%, 40%, 20% and 0%. In each case I will use distilled water to dilute the hydrogen peroxide. My 0% will be the control, it will be 10ml of distilled water. I am not expecting to see a reaction here. See table below to see amounts of hydrogen peroxide and distilled water to be used: After carrying out my preliminary experiment, I have decided to do my experiment as follows: Plan Method 1) Pour over 10ml of 100% hydrogen peroxide into the biurett (making sure the biurett is closed). Weigh 10 grams of the liver and put in boiling tube. Place bung on flask and have apparatus as drawn before. 2) Open the biurett and release exactly 10ml of the 100% hydrogen peroxide into the flask containing the celery, close the biurett. ...read more.

Conclusion

Also the readings could be affected by my speed of reaction of reading off the measuring cylinder. * The precision of measuring the amounts of hydrogen peroxide, liver and water I used each time could have also affected my results, as it was difficult to be completely accurate. To make the measurements more accurate I could have used pipettes rather than pouring the hydrogen peroxide and water. Improvements If I had the time I would do more repeats at each of the concentrations of hydrogen peroxide. This would make the average I took more accurate as it would mean errors, which could have been made in one experiment, would not affect the over all result so much. Also to improve this experiment I should extend it to include more time intervals. I think if I had continued to take readings every 10 seconds for another minute it would have produced a better graph as my curve would have flattened off more as the solution became saturated. I could repeat this experiment for more concentrations of hydrogen peroxide so I could have more rates of reaction to compare. This would make my results more reliable. I conclude that my final conclusion is valid because the evidence shows that my prediction was correct. This is seen in my results, on the graph it shows that the 100% concentration of hydrogen peroxide has the fastest rate of reaction. I feel that any uncertainties play little affect in making my conclusion any less valid as they can be justified by the inaccuracies I stated at the start of this evaluation. Deepak Chandi AS Level Biology Coursework 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

    The effects of Hydrogen Peroxide concentration on the activity of Potato Catalase

    4 star(s)

    Set up the apparatus as shown in figure 1.4 3) Add 5g of minced potato to the side-arm conical flask. Then add 10cm3 of buffer solution. Swirl gently to mix. 4) Add the bung to the flask, making sure the bung is securely in place.

  2. Marked by a teacher

    Enzymes - investigate how the substrate concentration (H2O2) affects the activity of catalase on ...

    3 star(s)

    Pipette - 5 ml 2 Use to transfer hydrogen peroxide from Burette - 50 cm3 1 Measure the volume of gas produced. Clamp and stand 1 Hold burette in straight in large beaker. 2.0 mol/dm3 hydrogen peroxide solution 250 cm3 Use to dilute to create required concentrations.

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

    Using the markings on the 50cm� beaker pour 50cm� of NaCl solution into a beaker and label it 'NaCl.' 5. Using the markings on the 50cm� beaker pour 50cm� of distilled water into a beaker and label it 'Water.'

  2. To investigate the rate at which hydrogen peroxide is broken down by the enzyme ...

    Another way to measure the rate of reaction is to weigh the beaker of the mixture throughout the reaction, however this is another inaccurate way of measurement because the change in the weight of the mixture due to the oxygen is so minimal compared to its volume, and at many

  1. The effect of Copper Sulphate concentration on Catalase activity on Hydrogen Peroxide.

    I hence assumed that the value for the optimum pH of the enzyme had to be in betIen 7 and 8. the reason why I didn't assume it would take a higher value is because such environments are only slightly alkaline, usually of value betIen 7 and 8.

  2. Investigate how concentration of the enzyme catalase in celery tissue alters the rate of ...

    At the maximum rate, at any given time, all the active sites of the enzymes are being implemented, so increasing the substrate concentration has no further effect on the rate of reaction. See below for a graph explaining this relationship.

  1. Investigating the effect of the Temperature on the Enzyme Catalase when it reacts with ...

    What safety Precautions should you take? These are the safety precautions that you should take when doing a Practical experiment. * Hydrogen peroxide is a corrosive solution, use gloves and handle it with care. * If spilled onto your skin then rinse it off with loads of water *

  2. WHAT EFFECT DOES SUBSTRATE HAVE ON THE RATE OF RESPIRATION IN SACCHAROMYCES CEREVISIAE?

    As I have mentioned before, enzymes have an active site that has a shape highly specific to that of the substrate. This means that they can usually act on one type of substrate only. When the substrate enters the active site of the enzyme, it causes the enzyme to change

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