Aim:
My aim in this investigation is to find out and investigate how the temperature affects the rates of reaction of the enzyme catalyse on its substrate hydrogen peroxide.
An enzyme is a biological catalyst, it alter the rate of reaction without being changed itself. Enzymes are proteins; they have a very precise three-dimensional shape, which forms a one specific active site on the enzyme. Each enzyme can only convert one kind of substrate molecule in to one kind of product molecule. These are specific.
What affects Enzymes?
· Temperature- Enzymes stop working if the temperature rises above 40ºC. Increasing the temperature alters the 3D shape and so the enzyme can no longer fit the substrate.
· pH- They work best in neutral conditions neither acidic nor alkaline.
What affect does catalyse have?
Catalyse is a very fast reacting enzyme, it is found in many living cells, it breaks down hydrogen peroxide to water and oxygen. In fact one molecule of it can deal with six million molecules of hydrogen peroxide in 1 minute. Hydrogen peroxide is toxic so needs to be changed into harmless substances.
Apparatus:
· Hydrogen peroxide 30ml
· 25ml cylinder tube
· Kettle
· Water bath
· Hot water bath
· Delivery tube
· Conical flask
The Term Paper on Potato An Hydrogen Peroxide And Liver And Hydrogen Peroxide
An investigation to compare the reaction rates between potato and hydrogen peroxide against liver and hydrogen peroxide through loss in mass. Background information: Catalase is an enzyme that is found in all cells. This means that it is an intracellular enzyme. And enzyme is a biological catalyst. A catalyst is some thing that speeds up a reaction without being changed itself. Because of this ...
· Thermometer
· Clamp
· Burette (60cm)
· Stop watch
· White tile
· Knife
· Ruler
· Rubber bung
· Goggles
· Flask
· Stop watch
· Potato
Method:
· Put goggles on
· Gather all the equipment
· I will then put all my apparatus together ensuring that I have assembled everything correctly
· Warm the water up in the kettle
· I will then get the white tile and place the potato onto the tile
· While the water is warming up, using the cork borer, (6cm) I will make 5 cylinders from the large potato, cutting them all accurately so they are the same length, measuring them accurately with a ruler(1cm each)
· Measure 25ml of hydrogen peroxide using a measuring cylinder.
· Select the temperature you are going to study
0ºC- iced water
25ºC-no extra equipment
37ºC-water bath required
55ºC-water bath required
100ºC-beaker of boiling water
· Fill up one of the water baths with normal tap water-about half way
· Then I will fill the burette with water using a funnel
· Add the measured hydrogen peroxide of 20 ml, and attach the rubber bung connected to the measuring syringe.
· While holding one end of the burette, run it and attach it to the clamp and place it into the water bath.
· Then fill in the 2nd water bath with the water that has been warmed up in the kettle.
· I will measure the temperature of the water using a thermometer and ensure that the temperature of the water is constant.
· Then attach the end of the delivery tube to the end of the burette ensuring that there are no air bubbles in the tube.
· Place the conical flask into the water maintained bath.
· Add the hydrogen peroxide into the conical flask
· Reset the stopwatch.
· Make sure that a table has been drawn in advance, so the results can be recorded easily and efficiently.
· Add the spud and close the conical flask using a bung.
· Start stopwatch and record volume of gas collected every 15 seconds.
· Repeat this procedure for as many temperatures as required.
The Essay on Thermal Pollution Water Temperature Oxygen
What is thermal pollution? One of the most serious ways that humans change the temperature of waters is through thermal pollution. The raising of the air or water temperature by artificial means is called thermal pollution. Thermally polluted water often undergoes biological changes that make it less valuable for drinking, recreational, habitat and industrial uses. What causes Thermal pollution? o ...
The Diagram below shows what all the equipment will look like once it has been set up:
Fair testing:
Throughout my investigation I will keep the following constant in order to ensure that my investigation is fair:
· The surface area of the potato
· Same volume of hydrogen peroxide in each part of the investigation
· The same size equipment e.g. boiling tubes as the readings for the results will be wrong if this is not constant.
· Use the same method for each experiment so that there won’t be any major differences. Only alter the temperature.
· Keep the amount of potato the same amount.
· Measure the temperature with a thermometer.
In order to ensure that the results I obtain are accurate and correct I will have to ensure I follow my plan and measure everything precisely.
I must:
· Measure the volume in cm” and amount of potato in grams to make sure that they are exactly the same mass before using them in the experiment.
· Do the experiment three times to ensure that there isn’t an odd result. Three is a good number to use as you can see if there is one odd one where if you just done the experiment twice then you wouldn’t know which one odd and which isn’t.
· Also to average out the results.
Safety: In order to stay safe I must:
· Wear goggles at all times
· Handle the hydrogen peroxide with care as it is irritant and corrosive
Risk Assessment:
Risk assessment
Name of chemical Hydrogen peroxide
Hazards Corrosive
In case of contact with substance Wash skin thoroughly with cold water immediately.
How to keep safe Make sure that you are always wearing safety goggles to protect your eyes.
My prediction:
From my research I predict that the enzymes will denature after 40ºC and any other temperature above that. Reason being that enzymes are proteins and their structure is three-dimensional. Increasing the temperature disturbs the intra molecular bonds that hold the 3D shape. Because of this the shape is altered. Enzymes have an active site. This fits into the substrate molecular, the LOCK AND KEY theory demonstrates this.
If the active site is altered the substrate will no longer fit in and so the enzyme doesn’t work properly.
The Term Paper on Hydrogen Peroxidev
Enzymes are biological catalysts that speed up chemical reactions, without being used up or changed. Catalase is a globular protein molecule that is found in all living cells. A globular protein is a protein with its molecules curled up into a ‘ball’ shape. All enzymes have an active site. This is where another molecule(s) can bind with the enzyme. This molecule is known as the ...
The rise of reaction rate is also due to the increase in temperature, relating to the kinetic theory. The higher the temperature, the faster they move. This happens but only to an optimum of 40ºC. The curve leading up to the optimum point is gradual but as it is reached it falls dramatically. The reason being that the active site is destroyed therefore no reaction can take place as there is only one specific active site per substrate.
Below I have done my preliminary testing:
I did preliminary work to verify the amount of hydrogen peroxide that was needed and what the size of the spud should be in order to determine some variety of results. Below are the results to the preliminary experiment that I did. The size of the borer is 6cm and the temperature is 50oC.
Volume of hydrogen peroxide (ml) Length of potato (cm) Volume of gas produced after 2 minutes (ml)
20 1 45.5
Repeat 36
30 1 33.6
Evaluation:
Overall I think that the results that I obtained during this investigation were rather good.
In my method, keeping the temperature constant throughout the investigation was hard to maintain, as the temperature of the contents of the tube would change quite quickly and therefore the hydrogen peroxide wouldn’t be at the temperature required. To overcome this problem I could keep the test tubes in a hot water bath for all the temperatures making sure that the water bath was the suitable depth. This would ensure constant temperature throughout the whole 5 minutes.
Also another problem that I observed on accuracy was that I didn’t allow the temperature to equilibrate to the right temperature. In this case I wasn’t using the correct temperature that I wanted, this could have led to some anomalous results. Ideally I should have brought the temperature of the hydrogen peroxide up to the needed temperature before adding to the potato. Looking back at my results I found some anomalous results in my findings. When averaging I used these results, which could have made the average either lower or higher than it should be. To improve this I should have missed these results. Not including some sets of results when making averages may have led to better values. Looking back at my results I found some anomalous results in my findings. When averaging I used these results, which could of made the average either lower or higher than it should be. To improve this I should have missed these results. Not including some sets of results when making averages may have led to better values.
The Essay on Effect Of Temperature On Hydrogen Peroxide
It is important that we use the apparatus carefully, as safety will be an issue throughout the whole experiment. We will wear goggles and an apron or lab coat to protect our eyes and clothes. As we are using enzymes and Hydrogen Peroxide we need to be extra careful, ensuring they don’t come into contact with our eyes, skin or clothes. Catalyse is an enzyme found in all living cells. It ...
My results are in line with those I predicted. Graphs indicate rise in temperature up a point leads to an increase in oxygen production. This is in line with kinetic theory. However it is very clear that after a certain temperature is reached the enzyme actually virtually stops. This supports my theory of lock and key fit. However optimum activity of enzyme is at about 37ºC this is as I had expected.
Overall, due to reliable repeats and in general predictions being confirmed I feel my results are reliable enough to make a conclusion. One of the main ways of improving this investigation is to change the method. I measure the volume of oxygen that was produced. In order to get pure oxygen without any other gases that are in the air I would use the same equipment but make sure that the gap between the rubber bung and solution was free from any other gases.
