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

Investigate the effect of copper sulphate on pepsin activity.

Extracts from this document...

Introduction

INVESTIGATE THE EFFECT OF COPPER SULPHATE ON PEPSIN ACTIVITY Plan: Pepsin is the main protease found in the stomach of mammals and other animals; the mammalian enzyme is sometimes called called gastric pepsin as opposed to other similar bacterial and fungal enzymes. Pepsin is first made by the body as an inactive form called pepsinogen and only becomes active when it is secreted by cells lining the stomach. Pepsin will digest a range of plant and animal proteins, including albumen, a protein found in the egg white of chicken eggs. Copper sulphate is a simple molecule which can have an adverse effect on the activity of some enzymes. Molecules which do this are referred to as inhibitors, as they inhibit a reaction's progress. Copper sulphate is called a heavy metal inhibitor, as copper is a relatively large metal atom. There are two types of inhibitors in biology. One type is called a competitive inhibitor, one which has a similar shape to that of the substrate being digested, and so it bonds with the active site of the enzyme. The other type is a non competitive inhibitor, one which is not similar in structure to the substrate, so it does not compete for the active site, but simply attaches itself to an area of the enzyme which distorts the active site, preventing the enzyme from catalysing reactions. Hypothesis: Copper sulphate will slow down the digestion of albumen by pepsin by acting as an inhibitor. The higher the concentration of copper sulphate, the slower the digestion of albumen by pepsin. Enzymes are commonly referred to as biological catalysts. This is because they are biological substances, but they can speed up various biological and chemical reactions, just like a catalyst. In chemistry, a catalyst works by providing a surface upon which reactions can take place. An enzyme works in a similar way, using what is called a 'lock and key' mechanism. ...read more.

Middle

it is an accurate way to set an environmental temperature for a reaction to take place in, and it is able to maintain that temperature for the duration of the experiment. I will use a stopwatch to accurately measure how long each sample has reacted for, and to stop the reaction when the time limit has been reached. Thermometers will allow me to check whether the contents of the test tube have reached the desired temperature before the reaction begins. This will improve accuracy of results. I will use albustix because they provide a quantitative test for proteins, and it is not as subjective as other tests. Risk assessment Pepsin: IRRITANT, HARMFUL This is bought in powder form; all enzymes must be treated with care as they have biological activity. In powder form: Wear chemical goggles and use rubber gloves, do not inhale dust. As 1% solution: Wear eye protection, rubber gloves and protective clothing. Do not introduce to skin or eyes. If this happens, flood the affected area with cold water for at least 10 minutes. Do not ingest. In case of emergency, seek immediate medical attention. Albumen: Very low health risk, store in a clear labelled container away from direct sunlight or high temperatures Copper sulphate: As 0.1 mol, 0.01 mol and 0.001 mol solutions: Use eye protection, protective clothing, do not ingest. A lab coat and goggles should be worn at all times during the experiment and in a laboratory. Implications on ethics and the environment: My experiment involves the use of copper sulphate, an inorganic molecule which is not harmful to the environment in small amounts I will also use pepsin, an enzyme. Enzymes in biology are not classified as living organisms, so it is acceptable to use them in experiments and testing. It is not harmful to the environment in such small amounts. However, I will be using albumen, extracted from the white of chicken eggs. ...read more.

Conclusion

The reliability of the results was also limited by the constraints. There was not sufficient time to repeat each experiment more than three times, and it was unfeasible to do more than four different concentrations. Improvements: Improvements to the method for further experimentation would be to use a colorimeter to measure the amount of protein remaining in the reacted solution, instead of using albustix, as they are subjective methods, and the colorimeter is quantitative and less subjective. I would also consider using a buffer solution to keep the temperature of the solution constant throughout the duration of the reaction. However, this complicates the experiment, and the experiment is sometimes affected by the actual buffer solution If I were to do the experiment again and I had more time, I would use a wider range of measurements and repeat each concentration at least 5-6 times For further research, I would see how concentration of enzymes and substrates affect the reaction, and temperature and pH can affect the rate of reaction. I could also test how temperature and pH affect the inhibitor molecules. Changing two variables in an experiment can make it an unfair test, but it can help to overcome some of the limitations of the experiment. Potential sources for error in my experiment could be a number of factors. I did not wash and sterilise the equipment myself so I had no way of knowing whether the equipment was contaminated or not. I had to trust that the technicians had cleaned the apparatus beforehand. Another source for error was the fact that I used albumen from egg whites. I used two different eggs, so one of the eggs could have contained more protein than the other, so it would have greatly affected my results. The last source for error was my judgement when analysing the colour of the albustix. The method was subjective, so there could easily have been some mistakes in the readings. Emile Khan 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

Here's what a teacher thought of this essay

4 star(s)

****
A good account of the investigation with all relevant background theory covered, good presentation of results and a well worded evaluation. A little more care with the use of precise scientific terminology would be beneficial.

Marked by teacher Adam Roberts 17/09/2013

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

    Analysing the vitamin C content in different fruit juices

    5 star(s)

    The volume of vitamin C solution used is recorded in a table. 6. Steps 1 to 5 are repeated twice to determine the average volume of vitamin C solution of concentration of 1.000g/100ml that is needed. 7. Steps 1 to 6 are then repeated using 0.75g, 0.5g, 0.25g, 0.125g of

  2. Effects of Copper Sulphate on the Activity of Catalase

    They therefore catalyse the forward and reverse reactions equally. Provided there is an excess of enzyme molecules, an increase in the substrate concentration produces a corresponding increase in the rate of reaction. At the point where there are sufficient substrate molecules to occupy all active sites on the available enzyme

  1. Investigating the effect of temperature on the activity of protease enzyme.

    Taking the average of 3 results per temperature will improve the accuracy and ensure that 1 anomalous result would not falsely manipulate the entire investigation. Results Temperature �C % Of light transition of milk and protease enzyme after 5 minutes 2nd result 3rd result Transmission with water and milk Average

  2. To investigate how temperature affects the concentration of vitamin C in orange juice (specifically ...

    Conclusion: The results show that the higher the temperature, the lower the amount of DCPIP was needed to react completely with the orange juice. On the graph of temperature versus amount of DCPIP used, I got a curve. This indicates that while the amount of DCPIP decreases as the temperature increases, at some point the amount of DCPIP remains constant.

  1. An experiment to show how protease enzymes are affected by temperature

    added to each beaker (1 beaker with the 3 boiling tubes of milk in and the other with 3 test tubes of enzyme) These were then left to equilibrate until the temperature was the same for all tubes. The temperatures where checked using a thermometer.

  2. Qualitative tests for carbohydrates

    Pentose gives a bluish green colour. The apparatus and materials utilised included:- * 6 boiling tubes * Water bath * Bunsen burner * Starch solution, glucose solution, fructose solution, sucrose solution, xylose solution and "UNKNOWN" solution * Bial's reagent, Molisch reagent, Benedict's reagent, Iodine solution, Seliwanoff's reagent, conc.

  1. Type - 1 Hypersensitivity Reaction

    The mask cells contain and release many biologically active secretory substances including histamine, which in turn bind onto the histamine 1 (H1) receptor on muscle (cells) surface. " The binding of allergens to IgE on mast cells triggers the release of several mediators, of which histamine is the most prevalent".

  2. An experiment to investigate the effect of temperature on the action of the enzyme ...

    The enzyme is said to be denatured because it can no longer form an enzyme-substrate complex as its active site has been unalterably changed. Another reason for the way enzymes act at lower temperatures is because they are protein based and so react like them, and are damaged by excessive heat or cold, as well as acidity.

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