Catalase Activity Experiment
Aim: to find out if different concentration of hydrogen peroxide
release different amounts of oxygen when in contact with catalase
enzyme.
Risk assessment: Hydrogen peroxide is corrosive and can therefore
irritate the skin and damage the eye if it comes into contact with
these. To prevent this extra caution must be taken to avoid contact
with the skin and goggles should be worn while carrying out the
experiments. Other sharp implements such as the scalpel used for
cutting the potato can be dangerous if the sharp side comes into
contact with the skin as it could cut it.
Prediction: I predict that as the concentration of the hydrogen
peroxide decreases, so will the level of oxygen produced. I think this
will happen due to collision theory. The collision theory is based on
the principle that for a reaction to occur the reacting molecules must
collide with each other with enough energy to react. The higher the
temperature the more energy the molecules will have and the faster
they will move, increasing the number of collisions and the chance
that the collisions will lead to a reaction. In terms of enzymes, we
are trying to get the substrate to collide with the enzyme and for the
enzyme-catalysed reaction to take place. Again, the higher the
temperature the more likely there will be effective collisions.
Fair test: The best way to ensure that the experiment is fair is to
make sure that the conditions are exactly the same for all the
different concentrations. Another way to ensure more accurate results
is to take repeat readings and then average out the answers so the
results are exact. The temperature of the water also affects how well
the enzyme works. Enzymes cannot function as well in a temperature
that is too hot or cold from their natural temperature. Using a
thermometer is important to keep this temperature constant. The slices
of potato should also be measured to be the same length so that amount
of catalase stays constant.
In the lab, Inhibiting the Action of Catechol Oxidase we had to investigate what type of enzyme inhibition occurs when an inhibitor is added. Catechol oxidase is an enzyme in plants that creates benzoquinone.Benzoquinone is a substance that is toxic to bacteria. It is brown and is the reason fruit turns brown. Now, there are two types of inhibitors, the competitive inhibitor and non-competitive inhibitor. For an enzyme reaction to occur a substrate has to bind or fit into the active site of the enzyme. In competitive inhibition there is a substrate and an inhibitor present, both compete to bind to the active site. If the competitive inhibitor binds to the active site it stops the reaction. A noncompetitive inhibitor binds to another region
The results of this experiment showed a specific pattern. As the temperature increased, the absorbance recorded by the spectrophotometer increased indicating that the activity of peroxidase enzyme has increased.At 4C the absorbance was low indicating a low peroxidase activity or reaction rate. At 23C the absorbance increased indicating an increase in peroxidase activity. At 32C the absorbance reached its maximum indicating that peroxidase activity reached its highest value and so 32 C could be considered as the optimum temperature of peroxidase enzyme. Yet as the temperature increased up to 60C, the absorbance decreased greatly indicating that peroxidase activity has decreased. This happened because at low temperature such as 4 C the kinetic energy of both enzyme and substrate molecules was low so they moved very slowly, collided less frequently and formed less enzyme-substrate complexes and so little or no products. Yet, at 23 C, as the temperature increased, enzyme and substrate molecules
For example, substrate concentration, enzyme concentration, and temperature could all be factors that affected the chemical reactions in our experiment. The concentration of substrate, in this case, would not have an affect on how the bovine liver catalase and the yeast would react. The reason why is because in both instances, the substrate (hydrogen peroxide) concentration was 1.5%. Therefore, the hydrogen peroxide would saturate the enzyme and produce the maximum rate of the chemical reaction. The other factor that could affect the rate of reaction is enzyme concentration. Evidently, higher concentrations of catalase in the bovine liver produced faster reactions, and the opposite occurs for lower concentrations of catalase. More enzymes in the catalase solution would collide with the hydrogen peroxide substrate. However, the yeast would react slower than the 400 U/mL solution, but faster than the 40 U/mL. Based on this evidence, I would conclude that the yeast has a higher enzyme concentration than 40 U/mL, but lower than 400
Catalase is a common enzyme that is produced in all living organisms. All living organisms are made up of cells and within the cells, enzymes function to increase the rate of chemical reactions. Enzymes function to create the same reactions using a lower amount of energy. The reactions of catalase play an important role to life, for example, it breaks down hydrogen peroxide into oxygen and water. Our group developed an experiment to test the rate of reaction of catalase in whole carrots and pinto beans with various concentrations of hydrogen peroxide. Almost all enzymes are proteins and proteins are made up of amino acids. The areas within an enzyme speed up the chemical reactions which are known as the active sites, and are also where the
The purpose of this experiment was to see if phenylthiourea (PTU) is a non-competitive or competitive inhibitor. Catechol, a phenolic compound found in the potato extract used will play the part of the substrate. Competitive inhibitors are known to bind to the active site of an enzyme and mimic the job of a substrate. This in turn causes the substrate to compete for a position at the active site and increase the concentration of substrate but the inhibitor is still at a constant level. If PTU were a competitive inhibitor the test tube carrying the extract would turn dark brown. Non- competitive inhibitors are known to bind on the enzyme and prevent the substrate from attaching
The alternate hypothesis is that there exists an optimal temperature for catecholase enzyme in which the catecholase enzyme can operate with the highest possible activity.
The shape of the molecules is changing and so the enzyme molecules can no longer fit into the gaps in the substrate that they need to and therefore the enzymes have de – natured and can no longer function as they are supposed to and cannot do their job correctly. Changing the temperature: Five different temperatures could be investigated. Water baths were used to maintain a constant temperature. Water baths were set up at 40 degrees, 60 degrees and 80 degrees (Celsius). Room temperature investigations were also carried out (20 degrees).
As temperature increases, rate of respiration increases, because particles move faster and with more energy, which in turn means more particles collide with enough energy to react. However, as temperature increases, enzyme stability decreases, so at temperatures above the optimum temperature, the rate will decrease, until all the enzymes have been fully denatured and all the active sites have been lost. Enzymes speed up reactions in organisms. Each enzyme works on a specific substance, called its substrate. The diagram below shows an “E” (an enzyme) catalysing the breakdown of “S” (the substrate) into two different products (“P”).
The Effect of pH on the Activity of Catalase Planning Experimental Work Secondary Resources Catalase is a type of enzyme found in different types of foods such as potatoes, apples and livers. It speeds up the disintegration of hydrogen peroxide into water because of the molecule of hydrogen peroxide (H2O2) but it remains unchanged at the end of the reaction.
Jim Clark. (2007). The effect of changing conditions in enzyme catalysis. Retrieved on March 6, 2001, from http://www.chemguide.co.uk/organicprops/aminoacids/enzymes2.html
Investigating the Effect of Substrate Concentration on Catalase Reaction. Planning -Aim : The aim of the experiment is to examine how the concentration of the substrate (Hydrogen Peroxide, H2O2) affects the rate of reaction. the enzyme (catalase).
We then cut our potato tubes with the cork borer and cut them with the scalpel so they were the same length and weighed them. We then put one potato tube in each test tube and then added the same amount sugar solution in to each tube. The concentration of sugar solutions varied in each test tube.
Method: [IMAGE] Equipment needed: Ruler Measuring Cylinder Scalpel Tongs Pipette Thermometer Tri-pod Stop-clock Gauze Delivery Tube Bunsen Burner Beaker Matches/Lighter Potato Hydrogen Peroxide Solution (20%) Water Lead Nitrate The skin of the potato was removed using a scalpel and then cut into 1cm², using a ruler to measure the size of each cube, four cubes are required for each experiment, and therefore at least 36 cubes are required for the full experiment to take place. Fill a beaker half way with water, and place a thermometer in the water. Allow the thermometer to warm to room temperature to gather an accurate reading, and measure the temperature, using the thermometer. A measuring cylinder was used to put 10ml of Hydrogen Peroxide Solution into a
How the Concentration of the Substrate Affects the Reaction in the Catalase Inside Potato Cells Introduction Enzymes are made of proteins and they speed up reactions, this means that they act as catalysts. Hydrogen peroxide is a byproduct of our cell's activities and is very toxic. The enzymes in our bodies break down the hydrogen peroxide at certain temperatures they work best at body temperature, which is approximately 37 degrees. At high temperatures, the cells begin to denature. This means that the hydrogen peroxide is prevented from being broken down because they will not 'fit' into the enzyme.[IMAGE] Objective I am going to find out how the concentration of the substrate, hydrogen peroxide affects the reaction in the catalase inside the potato cells.
the same brand of potato. By doing this I will make it a fair test.