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# Investigating Catalase.

Extracts from this document...

Introduction

ENZYMES Investigating Catalase Plan I will investigate how the concentration of hydrogen peroxide effects the volume of gas produced and how long it takes for the height of the foam produced to reach a certain height when reacted with the enzyme catalase, which is present in potatoes. In order to make my experiment fair, I must keep some factors constant: - INPUT CONSTANTS OUTPUT Concentration Volume of hydrogen peroxide Volume of Oxygen Surface area of potato Height of foam Temperature of hydrogen peroxide Cross section and overall length of potato Temperature of room Type of hydrogen peroxide Same potato pH of enzymes I chose to use concentration as my input variable. The other variables I could have changed are: - * Temperature (of Hydrogen peroxide) - changing the temperature would mean the hydrogen peroxide particles would have more energy meaning more successful collisions will occur making the reaction not only faster, but more oxygen would be collected in the same amount of time then if it was not heated. This is what I predict the graph would look like if I changed this variable: * Temperature of catalase (potato) - the temperature at which enzymes work best is called the 'optimum temperature' of 40�C. Anything below that and they slow down, anything higher than that and they become denatured. When an enzyme becomes denatured (at around 60�C), its molecules get too much energy making them unravel and so the reactant (hydrogen peroxide) would no longer fit into it. However enzymes do not die. By heating the potato to 40�C, the enzyme would be at its optimum temperature, therefore more oxygen would be collected and more foam formed. ...read more.

Middle

* If hydrogen peroxide spills onto your hand, you must wash it under water quickly 1. Arrange apparatus as shown above 2. Measure out the hydrogen peroxide and water into correct parts using a measuring cylinder then pour into test tube and measure the temperature (the temperature of the water should be room temperature) 3. Using the cylinder shaped potato cutter, get some potato and using the knife cut it to 3 cm 4. Now add the potato piece in the hydrogen peroxide (and water) and put the stopper in place. Remember to start the stopwatch at this point 5. After 5 minutes, measure the height of foam and take note of the volume of oxygen collected. Write the results in your table. 6. Repeat with the other concentrations, then repeat all four concentrations 3 times to ensure it is a fair test. I will record my results in a table: Concentration (%) Temp of (�C) Time (mins) Room temp (�C) Surface area of potato Height of foam (cm�) Volume of (cm�) SA of a cylinder= 2?rh+2?r� Diameter of cylinder cross section = 5 mm Radius (r) = 2.5 mm Height of cylinder (h) = 3 cm = 30 mm Surface area of a cylinder = 2?rh+2?r� = [2 x ? x 2.5 x 30] + [2 x ? x 2.5�] = 471.2 + 39.3 = 510.5 mm� = 51.05 cm� Obtaining Evidence Concentration (%) Temp of (�C) Time (mins) Room temp (�C) Surface area of potato (cm�) Height of foam (cm�) Volume of (cm�) 100 23 5 22 51.05 2.8 3.2 75 23 5 22 51.05 2.5 2.9 50 23 5 22 51.05 2 2.6 25 23 5 22 51.05 1.5 2.1 100 23 5 22 51.05 2.6 3.4 75 23 5 22 51.05 2.2 ...read more.

Conclusion

The biggest difference in volume of gas in the 'averages' graph however, was a difference of 0.6 cm� between the 25% and the 50% concentrations. In the first three graphs, the differences are only 'approximately' 0.5 cm�, because the results aren't all the same, but they are not far out. The lowest difference is 0.2 cm� in the 2nd experiment in the 'volume of oxygen produced' column between the 50% and 75% concentrations, and the highest difference is 0.8 cm� in the 3rd experiment in the 'volume of oxygen produced' column between the 25% and 50% concentrations. These differences are only 0.3 cm� more or less than 0.5 cm�, so they are still viable. There was only one anomaly in my 'rate of reaction' graph, which was the reading for the 25% concentration of hydrogen peroxide. Between the rests of the readings, there was a difference of 0.001 cm�/second, but between the 25% and the 50% concentration reading, there was a difference of 0.002 cm�/second. The reason for all these anomalies is that maybe my method slipt up a bit somewhere which meant some results were very close together and some were very far apart. The only difficulty I encountered when doing my experiments, was starting the stop watch, because I needed to put the stopper into the test tube at the same time, but I got over this problem by asking someone close by me to start it for me. I could have taken my investigation further, by heating the hydrogen peroxide to 40�C, which is the optimum temperature for enzymes. This would have meant that the enzyme would be at its peak activity rate, so more oxygen and foam would have been formed in the same time 5 minutes), because there would have been more successful collisions. ...read more.

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# Related GCSE Life Processes & Cells essays

1. ## What I will be investigating is the average height of foam that is produced ...

Below is the equation that I will use - Hydrogen Peroxide Oxygen + Water (H2O2) (Catalase) (O2) (2H2O2) (Substrate) (Enzyme) (Products) As you can see from above, the substrate I will be using is Hydrogen Peroxide, the enzyme is Catalase and the products of the experiment are Oxygen and Water

2. ## What influence does pH have on the enzyme Catalase?

Its fastest rate of reaction was 134mm/20s. This shows that this potato has a high amount of catalase and is in excellent health. This variation is only normal and if you look at the repeats of the individual potato results the repeats are all reasonably close.

1. ## How will whether the concentration of hydrogen peroxide when reacted with potato, determines the ...

Concentration: The higher amount of substrate to combine with, the faster the reaction due to the theory of successful collisions the more successful collisions the faster the rate of reaction. Lowering the amount of substrate reduces the rate due to less frequent collision between enzyme and itself.

2. ## Investagating the Action of the Enzyme Catalase On the Surface Area of a Potato.

They are specific, speeding up one reaction only 3. They work best within a small pH range which is different for each enzyme 4. They work fastest when warm, usually at body temperature (370C) 5. Above 500C, their shape is changed and is denatured causing them to stop working.

1. ## My hypothesis is that the higher the concentration of hydrogen peroxide the more catalase ...

This is similar to the idea of a higher pressure causing a faster rate of reaction. There are more molecules of acid, either because the volume of the container is less or because there are more molecules of the acid.

2. ## effect of hydrogen peroxide on potatoes

Safety: 1. Wear safety goggles, as Hydrogen Peroxide is an irritant that if gets in your eyes could be very harmful. 2. Putting all stools underneath the desk is vital as it could be dangerous of it is lying around and somebody knocks into it.

1. ## Decomposition of Hydrogen peroxide

This is because all the active site are occupied, so any extra substrate molecules have to wait until some of the active site becomes available. The graph shows reaction rate versus substrate concentration, the reason that the curve reaches a plateau, and does not increase any further at high substrate concentration is that the active site is saturated with substrate.

2. ## Hydrogen peroxide will breakdown to oxygen and water in the presence of Catalase. The ...

or attach themselves to the enzyme, altering the shape of the active site so that the substrate is unable to occupy it and the enzyme cannot function (non-competitive inhibitors). Inhibitors therefore slow the rate of reaction. They should not have affected this investigation, however, as none were added.

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