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

What is the effect of pH on the activity of the enzyme catalase?

Extracts from this document...


Lab Report #2: Enzyme Lab Aim: What is the effect of pH on the activity of the enzyme catalase? Variables: Independent: the different amount of drops of Hydrochloric acid (HCL)/Sodium Hydroxide (NaOH) and the substances which were tested. Dependent: The height to which the bubbles rose in the test tube after the addition of liver (measured in millimetres). Control: Amount of water, (20ml), Hydrogen peroxide (2.5ml) and liver puree (5 drops) in each of the beakers. Background Information: In living organisms, many chemical reactions must take place in order for it to function normally. These chemical reactions involve the breaking and reforming of chemical bonds between substrates of the reaction. However, though many chemical reactions occur spontaneously, processes such as the metabolic pathways, involve multiple chemical reactions which have to occur in a specific order. This is where a biological catalysts, known as the enzyme, plays a very important role. You see, enzymes have the task of catalyzing, (or speeding up), chemical reactions in a cell, all so that they can occur in a timely and sequential manner. The enzyme catalase, for instance, has the role of breaking down the toxic Hydrogen peroxide in animal and plant cells. Hydrogen peroxide is the byproduct of metabolism that has the ability to destroy cells if not removed. ...read more.


Add 2.5 ml of Hydrogen peroxide (H202) to the beakers. Measure the volume, (in millilitres), of the bubbles produced in each of the beakers. Record the results in a table. Data: Beakers Contents pH of substance Added contents Volume of bubbles (ml) 1 10 drops of HCl and 20ml of water 2 5 drops of liver puree & 2.5 ml of Hydrogen peroxide (H202) 12 2 20ml of water and 5 drops of HCL 4 5 drops of liver puree & 2.5 ml of Hydrogen peroxide (H202) 10 3 20ml of water 7 5 drops of liver puree & 2.5 ml of Hydrogen peroxide (H202) 0.8 4 20ml of water and 5 drops of NaOH 9 5 drops of liver puree & 2.5 ml of Hydrogen peroxide (H202) 2 5 10 drops of NaOH and 20ml of water 11 5 drops of liver puree & 2.5 ml of Hydrogen peroxide (H202) 1.9 Conclusion: Enzymes work within certain limits. One of these limits is pH, (otherwise known as the acidity level), at which an enzyme has an 'optimum' pH, which is basically the pH at which the enzyme works best. The further away an enzyme is from it's optimum pH, the less efficiently it begins to work, eventually becoming denatured. ...read more.


By mistake, some beakers were placed in the wrong order, and we were unsure as to whom they belonged to. We guesstimated the number of each of the beakers, and continued to work. In order to resolve this issue, though it would have consumed more time, we should have worked as a group, and dealt with one beaker at a time. This would have made the experiment far easier, and we would have definitely obtained better results. Another human error was the amount of Hydrochloric acid and Sodium Hydroxide added to the beakers. For beaker number 2, we were supposed to add 5 drops of HCl. However, after adding a few drops, we had lost count, as so we practically guessed the remaining drops which we would have to add. Though this probably wouldn't have made such a large difference in terms of the entire experiment, it could have still affected our results. To improve this error, we should have been more careful in measuring and adding the drops of HCl. Finally, we didn't measure the volume of the bubbles incredibly accurately. In beaker number 2, there was a disagreement between members in our group whether the bubbles rose 9ml or 11ml. Without properly measuring the volume, we simply assumed, by taking the average, that the bubbles were 10ml in height. To improve this, we should have accurately measured the volume of the bubbles in the cylinder. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & 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 GCSE Life Processes & Cells essays

  1. Marked by a teacher

    The Effect of pH on Catalase

    4 star(s)

    stop clock 1 bung (with 2 holes for plastic syringe and to connect to gas syringe) 1 clamp stand, clamp & boss 1 electronic balance 1 Bunsen burner 1 tripod 1 gauze matches narrow range indicator paper for pHs 4.5 - 8.5 grater potato 15 vol.

  2. Marked by a teacher

    The aim of this investigation is to find out what effect pH has on ...

    4 star(s)

    for the pressure to reach 10KPa Here are the results for the pre-test: 5KPa Pressure pH Time (s) 4.4 15.44 5.2 6.84 6.5 5.97 7.5 3.34 8.4 7.34 10KPa pH Time (s) 4.4 21.31 5.2 14.19 6.5 10.56 7.5 6.25 8.4 15.25 As you can see both experiments gave me

  1. Marked by a teacher

    Pectinase Lab

    3 star(s)

    This saved us time and energy and gave us a more liquid-like solution making it easier to pour the apple sauce and made the experiment easier to conduct. This gave us a more accurate measurement while finding the volume of the apple sauce.

  2. The effect of temperature upon the enzyme catalase

    Also the error bars for the set of results at 23oC and 40oC overlapped, the highest result for 23.4 was higher than the lowest result at 40. I also worked out the standard deviations for each set of data at each of the temperatures.

  1. What influence does pH have on the enzyme Catalase?

    However, some decreased a little. Potato 8 went from 65mm/20s at pH 7 to 56mm/20s at pH 8. This shows that the data peaked at its maximum somewhere between pH 7 and 8. There were three measurements from the table which I considered to be outliers as they did not

  2. The aim of this investigation is to find out the effect of pH on ...

    This demonstrates the lock and key theory. The three-dimensional structure of all enzymes can be affected by pH. Enzymes are made up of amino acids. Each amino acid has two groups (a -NH2 group and a -COOH group). pH is all about concentration of H+ ions. At low pH e.g.

  1. The effect of hydrogen peroxide on catalase if you change the temperature.

    In an enzyme catalysed reaction, such as the decomposition of hydrogen peroxide, this increases the rate at which the enzyme and substrate molecules meet and therefore the rate at which the products are formed. As the temperature continues to rise, however, the hydrogen and ionic bonds, which hold the enzyme molecules in shape, are broken.

  2. Structures and functions in living organisms. Revision Notes

    The walls of the collecting duct become less permeable to water and so urine becomes more dilute. 2.76 Recall that urine contains water, urea and salts. 2.77 Understand that organisms are able to respond to changes in their environment Living organisms are sensitive - they can recognise and respond to

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