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

Enzyme Investigation

Extracts from this document...


Biology Coursework Introduction I have to determine and choose one factor that will affect the rate of an enzyme and then investigate it. In this case the enzyme will be urease and the substrate will be urea. The following factors affect the rate that an enzyme works at: The temperature: Prediction - Reason - At higher temperatures usually there is an increase in enzyme activity. This is because as the temperature rises, the movement of enzyme molecules and substrate molecules increases. This increase in speed allows the substrate and enzyme to join and create the product quicker. If the temperature rises to high however, the enzyme activity declines rapidly as the heat denatures the enzyme. Below is an illustration of how the temperature can speed up the enzyme activity. Biology Coursework The pH: Enzymes are affected by changes in pH. The point where the enzyme is most active is known as the optimum pH. Extremely high or low pH values generally result in complete loss of activity for most enzymes. Prediction: Reason - I have predicted the optimum pH of Urease is 7, as urine is mainly made up of water (which has a pH7). Biology Coursework Substrate Concentration: Prediction: Reason - At very low substrate concentration, collisions between enzyme and substrate molecules are infrequent and reactions proceed slowly. ...read more.


I will use room temperature. I will also use 2cm3 of ethonic acid as it is just used to standardize a pH (starting point). Biology Coursework Method Biology Coursework Method Firstly prepare water bath to room temperature and note using a thermometer. Using a pipette put 5cm3 of Ethanoic acid into a test tube to form a starting point. Then put in 1cm3 of Universal Indicator using the pipette. The solution will turn into a red colour (acidic). Then place 5cm3 of Urea into the test tube. Then add 5cm3 of Urease and begin timing. The solution will go from red, to yellow and finally to green. Now stop timing. Repeat process 3 times and workout the average total. I should now change the quantity of Urease and start again. Extra Urea + water carbon dioxide + ammonia CO (NH2)2 + H2O CO2 + 2NH3 To test for the carbon dioxide I will use moist universal indicator paper and see if it turns orange. Obtaining Evidence Changes I made to my original plan - The only change I made to my original plan was to do an extra repeat (I got 3 readings for each experiment). This was because I had more time then I had initially anticipated and therefore made my results more accurate. ...read more.


What further work can be done? - This experiment can be taken further by using data-loggers that would provide much more accurate results. Each reading could be taken every 30 seconds. Also a different machine could have been used to measure the exact amount of urease in each experiment. More substrate concentrations also could have been used to prove the whole experiment was correct. More readings could have been taken to provide a more accurate average. Also a permanent constant temperature would result in better accuracy. Final Conclusion - In any chemical reaction, altering the concentration of reactants changes the rate at which the reaction takes place. Those reactions catalyzed by enzymes are no exception. If the amount of enzyme present is increased, the reaction speeds up proportionally. THIS IS TRUE AS LONG AS THERE IS PLENTY OF SUBSTRATE TO ACT UPON. This idea is best explained in a biology advanced studies book called 'Biochemistry' by Martin Carr and Bob Cordell. 'It it just like using a bus (i.e. the enzyme) to take a 1000 fans (i.e. the substrate molecules) to a football match (i.e. arrival = product). One bus will only do the job slowly, 2 buses will do the job twice as quickly, 3 will achieve three times the rate and so on. However, if there are only 20 fans to start with increasing the number of buses won't have great affect. Navad Khanzada 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

Here's what a teacher thought of this essay

3 star(s)

*** An experiment that has produced usable data, but that is missing key sections that are needed to gain the highest credit.
To improve
The missing relevant biological background theory sections need to be included. Suitably selected and cited references should be included to help inform the planning. A quantitative prediction should be included and this should be explained using biological knowledge. The key reaction involved in this experiment should be explained fully as it is this mechanism that is being used to determine the rate of reaction.
There is not enough consideration given to the key variables in the experiment. There should be a table or section detailing the way in which variables are controlled, manipulated or taken into account. The results of all trial or pilot experiments should always be included in an experimental report.
A thorough risk assessment should be included.
The apparatus appears to have been used competently but the table headings are lacking key details such as concentration or Molarity of the solutions used. The candidate said that means would be included in an analyzing evidence section but this was not included.
Analysing and Evaluating
This section appears incomplete. There needs to be a conclusion stated that comments on the trends and patterns in the data explained using relevant biological principles. The limitations of the results, and the conclusions based on them should be recognized and evaluated. The evaluation and suggestions for modifications would benefit from a more extensive analysis and some comments need more scientific detail. For example stating that a 'machine' could measure urease concentrations lacks the explanation needed for A level work.

Marked by teacher Stevie Fleming 22/08/2013

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 Effect of pH on Pectinase

    3 star(s)

    As soon as I had placed the apple puree into each funnel, I quickly and efficiently started the stopwatch and let it run for 5 minutes. After 5 minutes I removed the apple puree from above the measuring cylinders then measured accurately how much fruit juice had filtered through into each cylinder.

  2. Effects of Copper Sulphate on the Activity of Catalase

    But I wouldn't believe myself to have read a whole set of results inaccurately. The set of results for 20% H2O2 with no CuSO4 present seems to be less productive of oxygen than expected. I have to attribute this result on faulty apparatus; after all it was the last test for that part of the experiment.

  1. The Effect of Concentration on Pectinase Using Apple

    However it is also clear that at approximately 240 seconds, the graph begins to taper off. Slight resemblance to this trend can also be seen in the other concentrations. These graphs and tables alone do not show the rate of reaction for the five minutes.

  2. Type - 1 Hypersensitivity Reaction

    On the second exposure to egg albumin in the sensitised ileum, there was no contractile response, a reason to this was because the mast cells had already been ruptured, and through the degranulation of the mast cells, the histamine that had been released via the first exposure of the egg

  1. Investigating The Activity Of The Enzyme Lipase On Milk

    with three readings at each temperature, but also with three different milk samples, which would provide an even more accurate reading, as I could calculate an even wider average. Another problem was that I had to leave the milk solution and lipase solution to acclimatize for longer than I expected

  2. Investigating how different concentrations of a antibiotic effects the growth of a bacterium.

    It reacts with certain acids to form esters, e.g., with acetic acid it forms ethyl acetate. It can be oxidized to form acetic acid and acetaldehyde. It can be dehydrated to form diethyl ether or, at higher temperatures, ethylene. When reading the properties of Ethanol it can be seen that

  1. Investigating the effect of temperature on the activity of free and immobilised enzymes.

    Immobilised beads * 4cm3 lactase (?-galactosidase) * 16cm3 of 2% sodium alginate solution * 200cm3 of 2% calcium chloride solution in a plastic beaker * Semi-quantitative glucose test strips (Diabur 5000) * Muslin gauze * 10cm3 plastic syringe and barrel * Clamp and clamp stand * Short length of tubing, to fit plastic syringe and screw


    To control these variables I use the same diameter potato corer and cut all chips to the same length at all times. I will cut to the nearest millimetre, using a 15cm ruler. Also the volume of the sucrose solution will affect the experiment therefore the volume of the sucrose

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