The Effect of Heat on Enzyme Activity By: Kelly Duffy, Grade 9.
Problem • How hot does it need to be for pineapple enzymes to stop working?
Research • Enzyme • A catalyst can be used over and over again in a chemical reaction: it does not get used up. Enzymes are very much the same except that they are easily denatured by heat. • Denature • All enzymes are made of protein; that is why they are sensitive to heat, pH and heavy metal ions.
Hypothesis • If the pineapple enzymes are heated to 37° Celsius, then they will stop working and won’t be able to melt the jello.
Materials • A scale • One fresh pineapple • Two boxes of jello mix • A candy thermometer • A tray • A pot • 24 dishes
Procedure • Room was 23 degrees Celsius. • Experiment was not interfered with. • Two packets of jello mix were poured into a 22 by 33 cm glass pan. • 236 milliliters of boiling water were poured into glass pan. • Solution was stirred for two minutes. • 236 milliliters of cold water were poured into glass pan. • Solution was stirred for a minute. • Glass pan was placed in refrigerator at five degrees Celsius for four hours to jellify. • The jello was cut into 3cm slabs. • Pineapple was cut into 1cm cubes; core was excluded. • Twenty-four cubes in total.
Procedure • Initial temperature of water taken; 23.5 degrees C. • Dishes labeled at 5-degree increments after 23.5°C. • Pineapples placed in pot of water and put on low heat. • Pineapples taken out at 5-degree increments. • Pineapple cubes cooled for thirty-five minutes. • Pineapple cubes placed on jello slabs. • The first 13 pineapple cubes melt jello completely. • The next four only melt part of the jello. • The pineapple cubes stopped melting the jello after being heated to 103.5 degrees C.
Variables • Independent variable: The temperature of the pineapple cubes. • Dependent variable: Whether or not the enzymes are working. • Control: The pineapple that hadn’t been heated. • Constants: Pineapple, jello.
Conclusion • Hypothesis: If the pineapple enzymes are heated to 37° Celsius, then they will stop working and won’t be able to melt the jello. • The hypothesis was not supported. • The enzymes stopped melting the jello after being heated to 103.5° Celsius. • The experiment could be improved by testing the effect of heat on the enzymes of many fruits.
Thanks To… • Those in attendance listening • Works Consulted • http://www.education.com/science-fair/article/effect-of-heat-on-enzyme-activity/ • http://www.wordiq.com/definition/Enzyme • http://www.purchon.com/biology/enzymes.htm • Any Questions?