Identifying Variables.

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Identifying Variables

What are the reasons for controls?

* We did the experiment at the same temperature of room temperature the reason that temperature affects the rate of reaction. In fact over a range or 0 – 40 degree the rate of an enzyme controlled reaction doubles for every rise of 10 degree. Because according to Collision theory, heat increases molecular motion, thus the reactants move more quickly and chances of their bumping into each other are increased. As a result there is a greater probability of a reaction being caused. But after 40 degree (optimum point) enzyme denatures and is no more proportional to the rate of reaction because the structures of the enzyme and its active sites have been disrupted. Therefore we tried to do the experiment at the same time for accuracy of result.  

* Also under conditions of constant temperature every enzyme functions most efficiently over a narrow pH range. When the pH is altered above or below the optimum point, the rate of enzyme activity slows down. Changes of pH cause the enzyme shape to alter therefore; we did the experiment at the same pH when we started for a fair test.

* we did the experiment at the same substrate concentration, since the rate of an enzymatic reaction increases with increasing substrate concentration because there are enough active sites on the enzyme to react with the substrate. We used the same volume of 5cm3 since it is a good volume which doesn’t take a long time to clear.

* we used 5cm3 marvel so that it doesn’t take a long time to do the experiment and also gives a clear result.

* I started timing as soon as enzyme is added other wise we will not get accurate result because reaction would be happening whenever we add the enzyme. We decided to timing as soon as enzyme is added
(when the reaction starts). Still, the result is not going to be perfect since I am not a Robert which would start timing as soon as enzyme is added.

Apparatus

1.  a marker pen to write on beakers what solutions that they contain

2.  3 beakers to store different solution of 0.1 M hydrochloric acid, 4% Marvel & 1% trypsin solution.

 

3.  4% marvel solution since it doesn’t take a long time to do the experiment so I could finish up my experiment in time and it also gives a clear result.

4.  1% trysin solution since it is much easier to dilute with water than starting with 0.5 trypsin of solution

5.  hydrochloric acid to have a control because acid clears mik and to see whether other solution has reacted all by comparing with it

6.  Lab coat – for safety

7.  Goggles because acid blinds our eyes and enzymes irritate out eyes

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8.  A stopwatch to time how long the reactions take to clear the solution

9. a peace of white paper with crosses on the paper to observe how much solution have cleared

10. used 5cm3 of trysin and 5cm3 of marvel because it doesn’t take a long time to do the experiment and it also gives a clear result

11. water and acid for controls to compare with other solution to see whether the solution are fully reacted or not

12. specimen tubes and lids to shake and to compare with other solution.

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