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Has Anyone seen Confidential instructions for May/June 2011 paper 3 Biology? I want to know what kind of practical could possible come for exam.
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AS level Paper 3 Biology
- Thread starter heetamlani
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Ok Duh we're getting urease & urea tomorrow in Bio 33, Now what wud be the Improvements, Sources of error & Limitations for the experiment below?
Enzyme Concentration
In this investigation, we will examine what happens to the rate of a reaction when the amount of enzyme is reduced. We will use urease, an enzyme that converts urea to ammonia. The ammonia causes the pH of the water to increase (it becomes more basic). You will be able to tell when a reaction occurs because the urea solution also contains a pH indicator that is becomes yellow in acid but turns red when the solution becomes basic.
The object of this experiment is to measure the amount of time it takes for the solution to turn red if less enzyme is used.
C1. Create a hypothesis regarding the the amount of urease and the rate of reaction of Urea.
C2. Obtain four test tubes and add 2 cm of urea to each.
C3. Label three of these tubes 1 through 3; the remaining tube will not be used; it will serve as a control.
C4. Have your lab partner start timing as you add 15 drops of urease to tube #1 and then swirl the tube until it changes to a red color. Record the amount of time that it took for the urease to change to a red color.
C5. Add 5 drops of urease to tube #2 and then swirl the tube until it changes to a red color. Record the amount of time that it took for the urease to change to a red color.
C6. Add 1 drop of urease to tube #3 and then swirl the tube until it changes to a red color. Record the amount of time that it took for the urease to change to a red color.
C7. Record your results in the answer sheet.
C8. Did using less enzyme produce a reaction?
C9. What was the effect of using less enzyme in your experiment? If your experiment did not work as expected, what should have happened?
C10. In general, what happens to the rate of reaction as the amount of enzyme is decreased?
C11. Do your results support your hypothesis? Explain.
Enzyme Concentration
In this investigation, we will examine what happens to the rate of a reaction when the amount of enzyme is reduced. We will use urease, an enzyme that converts urea to ammonia. The ammonia causes the pH of the water to increase (it becomes more basic). You will be able to tell when a reaction occurs because the urea solution also contains a pH indicator that is becomes yellow in acid but turns red when the solution becomes basic.
The object of this experiment is to measure the amount of time it takes for the solution to turn red if less enzyme is used.
C1. Create a hypothesis regarding the the amount of urease and the rate of reaction of Urea.
C2. Obtain four test tubes and add 2 cm of urea to each.
C3. Label three of these tubes 1 through 3; the remaining tube will not be used; it will serve as a control.
C4. Have your lab partner start timing as you add 15 drops of urease to tube #1 and then swirl the tube until it changes to a red color. Record the amount of time that it took for the urease to change to a red color.
C5. Add 5 drops of urease to tube #2 and then swirl the tube until it changes to a red color. Record the amount of time that it took for the urease to change to a red color.
C6. Add 1 drop of urease to tube #3 and then swirl the tube until it changes to a red color. Record the amount of time that it took for the urease to change to a red color.
C7. Record your results in the answer sheet.
C8. Did using less enzyme produce a reaction?
C9. What was the effect of using less enzyme in your experiment? If your experiment did not work as expected, what should have happened?
C10. In general, what happens to the rate of reaction as the amount of enzyme is decreased?
C11. Do your results support your hypothesis? Explain.
Hey all.. Yhe 4 2mrw We might have Urease... N Transverse Section of leaf.. Hopefully..
http://www.scienceinschool.org/print/607 a link realted to enzymes urease.....
http://www.scienceinschool.org/print/607 a link realted to enzymes urease.....
http://www.xtremepapers.me/CIE/Internat ... 3_qp_5.pdf realated to enzyme urease...