Lab Report Using a Chemical Titration to Measure Rate of Conversion of Hydrogen Peroxide to Water and Oxygen
Overview:
In this laboratory you will use a chemical titration to measure and then calculate the rate of conversion of hydrogen peroxide (HO) to water and oxygen using the enzyme catalase.
Objectives:
Before doing this exercise, you should understand:
Ø the general functions and activities of enzymes
Ø the relationship between the structure and function of enzymes
Ø the concept of initial reaction rates of enzymes
Ø how the concept of free energy relates to enzyme activity
Ø that changes in temperature, pH, enzyme concentration, and substrate concentration can affect the initial reaction rates of enzyme-catalyzed reactions.
After doing the exercise, you should be able to:
ü measure the effects of changes of temperature, pH, enzyme concentration, and substrate concentration on rates of an enzyme-catalyzed reaction in a controlled experiment.
ü explain how environmental factors affect the rate of enzyme-catalyzed reactions.
Materials:
· 5mL and 10mL syringe
· 1mL pipet
· 60mL plastic cup
· beaker
· hot plate
· test tubes
· test tube tongs
· marker (to label)
· potassium promgemte
· sulfuric acid
· catalyze
· hydrogen peroxide
· bovine liver
· distilled water
· goggles
· apron
· gloves
Procedure:
Part A: Test of Catalase Activity
1. a) Transfer 10 mL of 1.5% (0.44 M) hydrogen peroxide
(H2O2) into a 50-mL glass beaker.
b) Add 1 mL of freshly made catalase solution.
2. a) Fill a glass beaker with 300 mL of water.
b) Place beaker on a burner and allow it to boil.
c) Transfer 5 mL of p...
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...ing to decrease until the last interval due to the small quantity of substrate left to react with after each passing interval.
5. Based on facts related to enzyme structure and chemistry, explain the inhibiting effect of sulfuric acid on the function of catalase.
§ The inhibiting effect that sulfuric acid takes on catalase is that when introduced it incredibly lowers the pH level of the catalase. Therefore, the sulfuric acid does not allow the enzyme to function properly when it comes to attaching itself to the substrate due to the difficulty of forming the needed hydrogen bonds as well as disulfide “bridges”.
6. Explain the effect of lowering the temperature on the rates of enzyme activity.
§ The effect of lowering the temperature on the rates of enzyme activity is a slower reaction rate because the lowering of the temperature would slow down the particles.
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
After conducting this experiment and collecting the data I would have to say that the optimal temperature for enzyme activity would have to be room temperature which in my experiment was thirty-four degrees Celsius. I came to this answer because the glucose test strip showed that at room temperature there was more glucose concentration that at either of the other temperatures. Due to temperature extremes in the boiling water the enzymes could no longer function because the breakdown of lactose stopped. The cold water also hindered the breakdown of the lactose but as the water warmed the enzymes were more active which can be seen in the results for the cold water at 20 minutes B. Describe the relationship between pH and the enzymatic activity of lactase.
Living organisms undergo chemical reactions with the help of unique proteins known as enzymes. Enzymes significantly assist in these processes by accelerating the rate of reaction in order to maintain life in the organism. Without enzymes, an organism would not be able to survive as long, because its chemical reactions would be too slow to prolong life. The properties and functions of enzymes during chemical reactions can help analyze the activity of the specific enzyme catalase, which can be found in bovine liver and yeast. Our hypothesis regarding enzyme activity is that the aspects of biology and environmental factors contribute to the different enzyme activities between bovine liver and yeast.
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
Input variables In this experiment there are two main factors that can affect the rate of the reaction. These key factors can change the rate of the reaction by either increasing it or decreasing it. These were considered and controlled so that they did not disrupt the success of the experiment. Temperature-
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).
What Affects the Rate of Breakdown of Hydrogen Peroxide by Enzymes Aim = == The aim of this experiment is to find out how temperature and concentration affect the breakdown of hydrogen peroxide by an enzyme (yeast). I hope to achieve reliable results that will confirm my predictions.
The Effect of Temperature on the Activity of the Enzyme Catalase Introduction: The catalase is added to hydrogen peroxide (H²0²), a vigorous reaction occurs and oxygen gas is evolved. This experiment investigates the effect of temperature on the rate at which the enzyme works by measuring the amount of oxygen evolved over a period of time. The experiment was carried out varying the temperature and recording the results. It was then repeated but we removed the catalase (potato) and added Lead Nitrate in its place, we again tested this experiment at two different temperatures and recorded the results. Once all the experiments were calculated, comparisons against two other groups were recorded.
I shall be measuring how much gas is given off. This will be done by measuring the amount of froth on the surface of the liquid. The oxygen released is collected in the form of these bubbles. The equation for the reaction is: (catalase) [IMAGE] H2O2 2H2O + O2 (hydrogen peroxide) (2 part water) (oxygen) I will change the concentration of H2O2 and O2 (making sure the volume stay the same, when one part of a H2O2 particle is taken, an O2 particle is added. Prediction
In this lab, it was determined how the rate of an enzyme-catalyzed reaction is affected by physical factors such as enzyme concentration, temperature, and substrate concentration affect. The question of what factors influence enzyme activity can be answered by the results of peroxidase activity and its relation to temperature and whether or not hydroxylamine causes a reaction change with enzyme activity. An enzyme is a protein produced by a living organism that serves as a biological catalyst. A catalyst is a substance that speeds up the rate of a chemical reaction and does so by lowering the activation energy of a reaction. With that energy reactants are brought together so that products can be formed.
While measuring the effect of the use of a catalyst and temperature on the reaction rate, several factors must be kept constant. During the reaction with a catalyst, the temperature will be kept constant (at room temperature), concentration, pressure and since the reaction involves liquids, the surface area will be kept constant at all times, however they must be mixed the same.
Figure 1 indicates that as the temperature increases the reaction rate increases. When the reaction rate reaches its maximum level this indicates the optimum temperature. The optimum temperature is where the enzyme preforms at its highest capacity. The optimum temperature in relation to this experiment was 37°C. This is expected because this reaction takes place in the human body which has a temperature of 37°C. Below or above this temperature the enzyme loses its ability to function (Santhosh, (2016)).
In this experiment three different equations were used and they are the Stoichiometry of Titration Reaction, Converting mL to L, and Calculating the Molarity of NaOH and HCl (Lab Guide pg. 142 and 143).
The first experiments investigate the order of reaction with respect to the reactants; hydrogen peroxide, potassium iodide and sulphuric acid by varying the concentrations and plotting them against 1/time. An initial rate technique is used in this experiment so ‘the rate of reaction is inversely proportional to time.’ To find the order of reaction in respect to the reactants, 1/time is plotted against the concentration of Hydrogen Peroxide using the equation: