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

How to measure the rate of a chemical reaction catalysed by an enzyme and then how I can change the rate at which the enzyme speeds up the chemical reaction.

Extracts from this document...


Biology coursework: GCSE I am going to investigate how to measure the rate of a chemical reaction catalysed by an enzyme and then how I can change the rate at which the enzyme speeds up the chemical reaction. The reaction I am going to investigate is Hydrogen Peroxide --> Water + Oxygen 2H20 --> 2H20 + 02 Catalyse is an enzyme found in all living cells. It causes Hydrogen peroxide to decompose into water (H20) and oxygen (02). Enzymes are able to increase the rate of a chemical reaction without being used up in the process. Enzymes are very efficient and small amounts at low temperatures can produce results that would usually require high temperatures and violent reactions. Increases in temperature can speed up the reaction; however enzymes become unstable when heated. Different factors that affect the speed of a chemical reaction that is catalysed by an enzyme are: Temperature When the temperature is increased the particles move faster as they have more energy. This results in more collisions, and the particles collide with higher energy, therefore the reaction is quicker. Heat can sometimes cause an enzyme to become out of shape, causing the substrate to no longer fit into the active site. Concentration If the solution is more concentrated it means there are more particles of reactant between water molecules. This makes collisions between important particles more likely to happen. ...read more.


Equipment * Washing up bowl half full of water * Large measuring cylinder * Two small measuring cylinders * A conical flask with a bung * Delivery tube * Stop watch * Goggles * 10cm3 hydrogen peroxide * 5cm3 enzyme Diagram Method 1. Fill the large measuring cylinder with water and invert it into the washing up bowl 2. Measure out 10cm3 hydrogen peroxide and pour into the conical flask 3. Using a clean measuring cylinder, measure out 5cm3 enzyme 4. Place the delivery tube so that one end of it goes up into the large measuring cylinder 5. Pour the enzyme into the conical flask with the hydrogen peroxide and immediately place on the bung and start the stop watch 6. Time for one minute and take a reading of the amount of gas in the large measuring cylinder Results Experiment 1 2 3 Strength of hydrogen peroxide (%) 100% 100% 100% Time (mins) 1 1 1 Measurement of gas (cm3) 95 97 91 Average 94.3 cm3 of gas I am now going to repeat the experiment although this time I will change the concentration of the hydrogen peroxide. I expect that the stronger the hydrogen peroxide is, the more gas will be collected in the large measuring cylinder. This is because as the concentration of substrate is increased, there are more hydrogen peroxide molecules available to fill the active sites and react. ...read more.


It is important to check that results are reliable because they make the experiment accurate. I feel that my results are reliable as took many precautions to ensure the reliability and fair tests of my experiments and there are no results that do not fit in with the line of best fit on my graph. I have collected sufficient results to make a firm conclusion that the stronger the concentration of the substrate, the quicker the reaction will take place when catalysed by an enzyme. Another way to investigate the effect of concentration on the rate of a reaction that is catalysed by an enzyme: 1. Set up apparatus as in the following diagram 2. Record the weight of the empty conical flask 3. Pour 5cm3 catalyse enzyme into the conical flask and record the weight of it minus the weight of the conical flask 4. Weigh the hydrogen peroxide and record the weight of it separately 5. Work out the sum of the hydrogen peroxide and catalyse to get the total weight of them added together in one conical flask 6. Pour the enzyme into the conical flask containing hydrogen peroxide whilst it is on the scales and start the stopwatch immediately 7. Time 1 minute and record the weight 8. Minus this from the total weight to calculate the weight of gas that has escaped during the reaction 9. Repeat the experiment with hydrogen peroxide at different concentrations A problem with this experiment is that very accurate weighing scales are needed to gain a reliable set of results. ...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. Peer reviewed

    Effect of enzyme concentration on rate of reaction

    4 star(s)

    The first one is the 'lock and key' model which suggests that the active site is rigid and is a perfect fit with the substrate molecule just as how the key would fit a lock. However, this theory is thought to be a simplification of the mechanism and the 'induced-fit' model was introduced.

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

    For the other concentrations, the line gradient showed that the rate of reaction slowed down slightly over the three minutes, but it didn't decrease and level off as predicted.

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

    They reduce the activation energy (Ea) required for a chemical reaction to take place. 9) The names of most enzymes end in -ase, this suffixes often being added to the name of the substrate. The Rate Of Enzyme Controlled Reactions The rate of an enzyme reaction is measured by

  2. An Investigation on the Effect of Enzyme Concentration on rate of hydrogen peroxide breakdown.

    Heating a substance means giving the molecules in that substance kinetic energy and hence increases molecular motion. Heating a solution containing enzymes results in increased speed at which the enzyme and substrate molecules travel.

  1. Investigation in to factors affecting the rate of an enzyme catalysed reaction.

    Once this point has been reached the bonds holding the enzyme molecule in its shape begin to break, causing it to denature. A very similar thing happens with pH, most enzymes work fastest at a pH of about seven, which is fairly neutral, where as protease pepsin have a different

  2. Experiment To Investigate The Effect Of Concentration On An Enzyme Based Reaction.

    molecule, making it harder for a substrate molecule to bind with it as the active site will change shape. pH affects the ionic bonds in the enzyme structure as well as the 'R' groups that line the active site with which the substrate physically binds.


    I believe our timing may have been inaccurate or the temperature reading might have been wrong too. We could have used more computerised equipment for our experiment like digital thermometers to produce more reliable and accurate results. We could have also been more precise when measuring the enzyme (there may have been too little)

  2. Factors that affects the rate of chemical reaction?

    There're still many types of enzymes, that involve in many biological process, such as making the heart beats, expanding and contracting the lungs, facilitate the process of turning nutrient into various substance that is use for tissue building, making new blood cells and convert chemical energy to make muscle move.

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