Eks Bab4 Kepekatan Enzim

Berdasarkan maklumat di bawah, rancang satu eksperimen untuk mengkaji kesan kepekatan enzim amilase air liur terhadap kadar tindakbalas biokimia. Terdapat banyak faktor yang mempengaruhi kebolehan enzim dalam memangkinkan sesuatu tindakbalas biokimia. Antara faktor-faktor tersebut ialah pH, suhu, kepekatan substrat dan kepekatan enzim. Apabila kepekatan enzim bertambah, maka terdapat lebih banyak molekul enzim. Berdasarkan maklumat di atas, rancang satu eksperimen dalam makmal untuk mengkaji kesan kepekatan enzim amilase air liur terhadap kadar tindakbalas biokimia. Perancangan kerja eksperimen anda perlu meliputi aspek-aspek berikut:

1. 2. 3. 4. 5. 6. 7. 8. 9.

Pernyataan masalah Objektif kajian Hipotesis Pembolehubah Senarai alat radas dan bahan Teknik yang digunakan Kaedah atau prosedur eksperimen

Cara data dikomunikasikan Kesimpulan

[17 marks]

CADANGAN JAWAPAN : AIM: To study/ investigate the effect of salivary amylase / enzyme concentration on the rate of (biochemical) reaction PROBLEM STATEMENT: What is the effect of salivary amylase / enzyme concentration on the rate of (biochemical) reaction ? HYPOTHESIS The higher the salivary amylase / enzyme concentration, the higher the rate of (biochemical) reaction until it reaches a maximum rate VARIABLES Manipulated: Salivary amylase / enzyme concentration Responding:Rate of (biochemical) reaction // time taken for breakdown of starch Fixed: pH, substrate concentration, temperature

APPARATUS AND MATERIALS Beakers, test tubes, syringe, dropper, glass rod, white tile, thermometer, stopwatch, water bath (wire gauze, bunsen burner, tripod stand), test tube rack, starch solution, iodine solution, salivary amylase/ saliva, distilled water TECHNIQUE: Measure and record the time taken for breakdown / hyrolysis of starch// iodine solution to change colour from blue black to brownish yellow using a stopwatch PROCEDURE: Able to list down the complete and correct procedure used based on the following criteria K1 – Technique of assembling the apparatus to carry out the experiment. K2 – Technique of fixing the constant variables K3 – Technique of changing the manipulated variables K4 – Technique of measuring the responding variables K5 - Technique of taking precautions to increase accuracy Suggested Answer: 1. Label six test tubes as A, B, C, D, E and F. (K3) 2. Fill each test tube with solutions as shown in the table below. (K1, K3) Test tube Volume of saliva (ml) Volume of distilled water (ml) A 0.5 2.5 B 1.0 2.0 C 1.5 1.5 D 2.0 1.0 E 2.5 0.5 F 3.0 0.0 3. Drop a few drops of iodine separately on a white tile. (K1) 4. Pour 4 ml of starch solution into test tube A. (K2) 5. Start the stopwatch immediately. Use a dropper to withdraw a small amount of the mixture and add it to a drop of iodine on the white tile immediately. (K1, K5) 6.Observe the colour change in iodine. (K4)

7.Carry out the iodine test at an interval of 30 seconds until the blue-black colour no longer appears and the iodine solution remains brownish yellow. (K1, K2) 8. Record the time taken for the complete hydrolysis of starch. (K4) 9. If blue black colour is still produced after eight minutes, terminate the experiment with the reaction mixture. (K5) 10. Repeat steps 4 to 8 for test tubes B,C, D, E and F. (K1, K3) 11. Record all your observations. (K4) 12.Plot a graph of rate of reaction [1/time] against enzyme concentration. (K1) RESULT:

CONCLUSION: The higher the salivary amylase / enzyme concentration, the higher the rate of (biochemical) reaction until it reaches a maximum rate. Hypothesis is accepted

A group of students did a study on the function of enzymes as an organic catalyst that can regulate and increase the rate biochemical reactions in the cell. Enzymes are very sensitive to a change in temperature and functions efficiently at an optimum temperature. Design an experiment to study the effect of different temperatures on the activity of salivary amylase on starch. The planning of your experiment must include the following aspects: · · · · · · · · ·

Statement of identified problem Objective of study Variables Statement of variables List of materials and apparatus Technique used Experimental procedure Presentation of data Conclusion

Sample answer: Problem Statement How does different temperatures Affect the activity of salivary amylase? Aim: To study the effect of different temperatures on the activity of salivary amylase . Variables: Manipulated variables: Temperature. Responding variables: Time taken for hydrolysis of starch to be completed// Rate of reaction. Controlled variable: enzyme concentration Hypothesis: The rate of reaction of salivary amylase on starch increases with an increase in temperature until it reaches the optimum temperature. Apparatus & Materials: Test tube, a dropper, a stopwatch, beakers, a thermometer, a white tile, a Bunsen burner, a tripod stand, test-tube rack, a wire gauze. 1 % starch solution, salivary amylase solution, ice cubes, distilled water, iodine test solution. Technique Measure and record the time taken for hydrolysis of starch to be completed using stopwatch Procedure: 1. Collect 5 ml of saliva and dilute it with 5 ml of distilled water and labelled test tube X. 2. Put 1 ml saliva in each test tube labelled A, B, C, D and E. 3. Pour 5 ml of 1 % starch solution into each test tube labelled A, B, C, D and E. 4. Immerse test tube A and X, in water bath where the temperature is fixed at 5C and leave it for 10 minutes. 5. Prepare a piece of white tile and drop iodine solution on it. 6. After 5 minutes pour 2ml of saliva from test tube X to the starch solution in test tube A. Start the stop watch. 7. Repeat the iodine test for the mixture from test tube A at intervals of 1 minute. 8. Record the time taken for the mixture from A to change in colour of iodine solution until it does not change. 9. Repeat steps 4 to 8 for test tubes B, C, D and E with water temperatures fixed at 28C, 37C, 45C and 60C respectively. 10. The results are recorded in a table.

Result:

Conclusion: The rate of increase of enzyme action increases with an increase in temperature until it reaches the optimum temperature. Hypothesis accepted