Enzyme Lab Using Jello
Enzymes are known as protein catalysts. The name protein catalyst suggests that most enzymes are made of proteins. A catalyst is a substance that speeds up chemical reactions without being consumed in the process. (Giuseppe, M 2002, p.69). After a reaction has been catalyzed, the catalyst can be used again to catalyze the same reaction. Enzymes reduce the activation energy (minimal energy) it takes for a reaction to take place. Enzymes can either catabolize (destroy), or anabolize (build up) a chemical system.
The substrate is the reactant that an enzyme acts upon as it catalyzes a chemical reaction. (Giuseppe, M 2002, p. 69). The substrate is bound to a specific site on the enzyme and only that specific enzyme can act on a specific substrate. Some enzymes in the body require either non-protein cofactor or a coenzyme which enables the enzyme to carry out its specific function. A non-protein cofactor found in the body of humans is called insulin. Insulin brings the glucose from red blood cells pass the cell membrane and into the cell.
Enzymes are inhibited by a variety of organisms. These organisms are called competitive inhibitors or noncompetitive inhibitors. Competitive inhibitors inhibit enzymes on their active site so that the substrate cannot fit into the active site. Noncompetitive inhibitors bind to a site other than the active site thus changing the shape of the enzyme to the point that it looses affinity for the substrate. (Giuseppe, M 2002 p. 73). Feedback inhibition is a method that controls the metabolic process in the body. (Giuseppe, M, 2002 p. 73). It tells the enzymes when to either produce more or less products.
Enzymes can be denatured; this means that an enzyme can lose its function due to forces acting on the enzyme. Protein denaturing can be caused by two factors: temperature and pH. Every enzyme in the body has a temperature at which it works best. The human enzyme works best at a temperature of 32oC. (Giuseppe, M 2002 p. 73). If this temperature is surpassed, protein denaturing occurs and the enzyme will lose its function. Another factor that plays a role in protein denaturing is pH (acidity of the body). If the pH of a protein increases or decreases past a crucial point, the protein is also denatured and it will lose its functions.
To test for the presence of enzymes in fruits and the specificity of those enzymes, as well as to identify and show the susceptibility of enzyme to certain environmental factors (temperature, pH) originating in the enzyme’s environment.
The Pineapple and Kiwi fruits will contain enzymes which denatures gelatine protein molecules. The proteolytic enzymes in Pineapples will be denatured at a temperature of 75oC.
1 envelope gelatine
thawed pineapple juice concentration, 1 measuring cup
hot water bath
9 test tubes
7-5 ml pipettes
1 test tube rack
test tube tongs
Enzyme Lab 1
Test tubes were numbered from 1 to 9
Gelatin was prepared in a mixing bowl
Half of the recommended boiling water amounts was dissolved well with a spoon 4.
3ml fruit juiced was placed in each test tube
Tube 1 – water only
Tube 2 – pineapple
Tube 3 – kiwi
Tube 4 – lemon
Tube 5 – apple
Tube 6 – papaya
Tube 7 – strawberry
Tube 8 – Soy solution
Tube 9 – Worcestershire solution
10 ml. gelatine mixture was added to each test tube
The test tubes were shook well to ensure proper mixing
The test tubes were placed on a test tube rack to be refrigerated overnight. Observations were recorded. 8.
On the second day, the contents of each test tube were checked for solidification of contents....
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