Investigating The Effect Of Changing Temperature On The Activity Of The Enzyme, Catalase PDF

Preview

Summary

class assignment...

Description

Investigating The Effect Of Changing Temperature On The Activity Of The Enzyme, Catalase Introduction: Enzymes are macromolecular biological molecules (a type of proteins) that aid in catalyzing important chemical reactions in nearly all living organisms, but are unaltered in the process itself. Enzymes are crucial to life and assist in a variety of important functions such as digestion and metabolism. Metabolism is the group of processes that include respiration (production of energy), anabolism (when smaller molecules form to construct one larger molecule), and catabolism (when one larger molecule is destroyed and forms smaller molecules). Enzymes are a very selective group, meaning each enzyme only helps speed up a certain reaction. Hydrogen Peroxide is a by-product of numerous biological processes like aerobic respiration and is a toxic substance to most living things. Therefore, it needs to be removed from the organisms systems quickly before it is able to harm cells. This is where Catalase comes in. Catalase is an enzyme produced by the cells in the body that catalyzes the reaction to break down Hydrogen Peroxide (H₂O₂) into Water (H₂O) and Oxygen (O₂). The chemical equation and word equation for this reaction is:

Like everything else in the world, there are certain criteria that need to be met for something to function properly. A lot of environmental changes can decrease proper function of an enzyme and some examples are: Temperature, pH, and Substrate Concentration. Temperature is a factor that is constantly changing in an environment and one that will affect enzymes the most. Enzymes are highly specific not only in the reactions that they catalyze but also the temperatures that they work at. Decreasing temperature can affect the rate of the reaction of the enzyme and substrate because the temperature is not optimal for the reaction to occur properly. When the temperature is low the movement of the molecules slows down and therefore the reaction occurs slower than it would at optimal temperature. Increasing the temperature is able to affect the structure of the enzyme. High temperatures beyond the optimum temperature can denature (destroy the characteristic properties) of the enzyme. This means that properties will be changed and it will dramatically affect the process of the reaction. If the temperature is at optimal temperature the reaction will occur faster and will not affect the enzymes because that is the temperature that they work at their best. The molecules of the enzymes will be moving at the proper speed and therefore the optimal temperature will not affect the reaction rate. This is the way that temperature affects functional efficiency of enzymes. pH is also a reason that can influence a change in functional efficiency. Alterations in pH affect not only the shape of an enzyme but it may also alter the shape or change properties of the substrate that the enzyme acts upon so that either the substrate is not able to bind to the active site of the enzyme or it is unable to undergo catalysis. If the enzyme is working in conditions where it is the optimal pH then the reaction rate will increase and the reaction will not be compromised by any pH factors. This is because the pH is at the condition that the enzyme needs it to be at. This is how pH is able to affect the functional efficiency of enzymes. Substrate concentration is another environmental factor that influences an enzymes functional efficiency. Substrate concentration refers to the quantity of the substrate (how much substrate is available). The more substrate that is available the faster the rate of reaction will be. Enzymes bind to the substrate that they react with and form an enzymesubstrate complex and this is also called the ’lock and key mechanism’. The substrate will continue to bind to the enzymes active sites and this will occur until all active sites have been occupied and no more substrate is able to be accepted by the enzyme. When all active sites are taken up, this is the maximum rate at which the reaction can occur at and this is known as the ‘saturation point’. This is how substrate concentration can affect functional efficiency of enzymes. Catalase works at its best when it is at 37 degrees Celsius (Body Temperature) and at a pH of 7.4 (Neutral). Catalase is found predominantly in the liver in the liver cells and in peroxisomes. Peroxisomes are small organelles that are present in the cytoplasm of many cells. these cells contain the enzyme, catalase and usually some oxidases. Oxidases are an enzyme that promotes the exchange of a hydrogen atom from a particular substrate to an oxygen molecule to either form water or hydrogen peroxide. Catalase also has a variety of industrial applications for example, in the food industry, it is used in combination with other enzymes to preserve foodstuffs, it is employed in the rubber industry to form oxygen,

which converts latex to foam rubber, and it assists in the manufacturing process of beverages and certain food items. Commercial catalases are used to break down the hydrogen peroxide in wastewater. Catalase is the fastest known enzyme because they are some of the most efficient enzymes that are found in cells. Each catalase molecule is capable of decomposing millions of hydrogen peroxide molecules every second.

Aim: To investigate the effect of changing temperature on the activity of enzyme catalase. Hypothesis: Changing the temperature will affect how efficiently the reaction occurs. Since catalase works optimally at 37 degrees Celsius it will work properly around that temperature. Increasing and decreasing the temperature will affect its functional efficiency. The more foam (oxygen bubbles) will be produced at around 35 0 C because it is the closest to body temperature. The temperatures lower than 350 C, the reactions will take longer to occur because it is lower than the optimal temperature. Temperatures higher than 35 0 C will react even slower because they are beyond optimal temperature and the enzyme might/might not have been denatured. Apparatus:

5 test tubes

70ml Hydrogen Peroxide

1 Leaf of Spinach

Ruler (cm)

Mortar and pestle

Kettle

5 large beakers each with 20 ml water at different temperatures

Ice cubes

(O0 C, 150 C, 250,C 350,C 50oC) Measuring cylinder (ml)

Stirring rod Safety Glasses (PPE)

Thermometer (o C) Strainer Stopwatch (min & sec) Small Beaker 160ml Water Piece of Paper and Pen to record Results Test Tube Rack Permanent Marker Risk Assessment:

Safety Risk

Cutting yourself with the knife

Description Of The Safety Risk



Whilst cutting the spinach you could cut your finger.

Safety Precautions Minimizing The Safety Risk  Wear safety gloves to prevent cuts  If you cut your finger, clean your wound and have it bandaged as quickly as possible.

 Hot liquids

 

Hot liquids could be bumped, fall, or spill from the table and cause serious burns and/or injury Heated flasks could break and cause injury

 

 Chemicals Spilling



Glass equipment breaking



Chemical spilling on your skin causing harm or injury





 

Equipment either breaking on the table or floor if you drop it. They can also break if the equipment get too hot and the glass breaks if you squeeze it. Broken glass equipment can cut you severely and cause very serious injuries.

 

 Slipping on floor if floor is wet.



Water and/or chemicals spill on the floor causing it to become slipper and you/other people slip and fall causing harm and/or injury to yourself and others.



If a hot liquid spills and burns your skin, place the burnt area under cold running water for at least ten minutes. Wear solid, closed shoes. Let the flasks cool down before toughing them and if you need to move them then wear safety gloves to prevent injury. Be careful when using chemicals and don’t hurry when pouring in liquids into a flask, beaker etc. If in any case a chemical spills or makes contact with your skin, wash it off as quickly as possible.

To prevent dropping it, hold equipment firmly when moving it. If the equipment is hot then, let it cool before touching and/or moving it If equipment breaks and it cuts you and causes injury. Stop whatever you are doing and inform the teacher about what has happened. If chemicals or water spills on the floor, quickly clean it up using a paper towel and afterwards make sure that none of the surroundings are wet. This will prevent any injury from slipping on a wet floor. If you slip and injure yourself, tell someone (if you are not able to) to inform the teacher so that they can get help.

Variables and the Control: Independent variable: The temperate of the water baths is the independent variable as it is the thing that I will change Dependent: The amount of oxygen (foam) produced in the reaction and the time taken for the hydrogen peroxide to react with the enzyme, catalase. These measurements are the dependent variable and will indicate the functional efficiency of the enzyme, catalase. Controlled variables: The amount of hydrogen peroxide in each test tube, the amount of water in each test tube, the size of the test tubes. Control group: The water bath at 25o C is the control group because it is at room temperature. Procedure: 1. Collect all apparatus and set up the experiment 2. Gather 5 test tubes and place them in a test tube rack and label the test tubes A,B,C,D,E 3. Cut the leaf of spinach into six equal pieces and crush each piece individually in the mortar and pestle. 4.

Add 50 ml of water to the crushed spinach and mix using the stirring rod to form a slurry and then strain the fluid into a small beaker. That fluid is the catalase.

5.

Prepare the 6 water baths. Add ice and water into one beaker to bring the temperature down to O 0 C, add a bit of ice to the second beaker to bring the temperature down to 15 0 C, the third one should be at room temperature which is around 25oC, the fourth beaker should be at 35 0C which is close to body temperature, and for the last one, boil water in a kettle to bring the temperature up to 500 C.

6.

Measure 10ml of the catalase fluid using the measuring cylinder and pour 10ml into each of the test tubes.

7.

Wear safety goggles and pour 5ml of Hydrogen Peroxide and pour into each test tube and place one test tube into each of the water baths.

8.

Record the time that it takes for each of the reactions (bubbles) start to form, record down the time it has taken on a piece of paper.

9.

When each of the reactions have occurred, measure the height of foaming using a ruler and record it down on the piece of paper.

10. Wash all equipment thoroughly and repeat experiment once for more reliable and valid results. Use the extra hydrogen peroxide and water for the repeated experiment. Diagram of the Setup:

Hydrogen peroxide + catalase solution

Water bath

00 C

150 C

250 C

350 C

500 C

Results: The temperatures will be varied to see at which temperature catalase works at its optimal condition. The height of foaming will be measured to see if the reaction is functioning properly. The oxygen bubbles produced will be the reaction and the higher the ‘height of foaming’ the better the reaction. The time taken to react will show if the reaction is occurring properly. If the reaction takes long to occur it is not reacting optimally. If the reaction is quicker then the reaction is occurring properly and at its optimal point. Test Tube A (O0 C)

Height of foaming (cm)

B (150 C) C (250 C) D (350 C) E (500 C) Discussion: 1.

Does the data you collected support or disprove your hypothesis? Explain why.

Time To React (min, sec)

2.

Are there any patterns/trends in the data you collected? Explain these patterns/trends.

3.

Assess the accuracy of any measurements and relative importance of the data gathered.

4.

Assess any uncertainty that may be present in the measurement of the data.

5.

What were some of the limitations within the procedure of your investigation?

6

What modification/s did/could you make to improve the procedure?

7

Discuss the possible effects of these modifications on the outcomes of the investigation.

8

Evaluate the validity of your first-hand data in relation to the area of investigation.

Conclusion:

Bibliography: The Editors of Encyclopedia Britannica, Enzyme, https://www.britannica.com/science/enzyme [Accessed 18/02/2018] Smith.B, How Does Temperature Affect Catalase Enzyme Activity?, https://sciencing.com/temperature-affectcatalase-enzyme-activity-7776025.html, [Accessed 20/02/2018] Castro.J, How Do Enzymes Work?, https://www.livescience.com/45145-how-do-enzymes-work.html, [Accessed 20/02/2018] Brooklyn College City University of New York, The effect of pH on enzyme activity, http://academic.brooklyn.cuny.edu/biology/bio4fv/page/ph_and_.htm [Accessed 22/02/2018] The Editors of Encyclopedia Britannica, Catalase, https://www.britannica.com/science/catalase, [Accessed 22/02/2018] Humphreys.K, Surfing Biology 1 & 2, science Press, Marrickville, NSW, 2018 Goodsell.D, Catalase, http://pdb101.rcsb.org/motm/57, [Accessed 1/03/2018]...