Biochemistry Lab Report - Practical Study On Dilution Experiment PDF

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FACULTY OF RESOURCE SCIENCE AND TECHNOLOGY DEPARTMENT OF CHEMISTRY

STB 1083 : Biochemistry

Biochemistry Practical 1 Dilution Experiment

DATE OF SUBMISSION

:

09/04/2018(TUESDAY)

AERON RONNY JELIUS ( 58394) SIXTUS THOMAS (57980) NAME

: ROBSON GAIT ANAK SANTE PAULUS(57718) LUQMANUL HAKIM BIN MOHD IDRUS (58845)

LECTURER NAME

:

DR. AZHAM

Introduction Dilution process is a process where the measured volume of concentrated solution of analyte with a buffer to make less concentrated solutions. This process remain the amount of solute constant, meanwhile the total amount of solutions is increasing, by that means its final concentration is decreasing. Dilution process also can be achieved by mixing the highest concentration of solution to the lesser concentration of the identical solution. Formula to calculate the diluted solution is

C1 V 1 = C 2 V 2 where;

C1 = original concentration of a solution V 1 = original volume of a solution

C2 = concentration of diluted solution V 2 = final volume of diluted solution

In this experiment, 1.0% (w/v) starch solution was used and put in five test tubes. Starch solution is usually used as indicators to detect the presence of iodine. In general, 1.0% of starch solution will produced a deep blue-black colour in the presence of iodine solution (Flinn Scientific, 2017). If the starch solution were too diluted, the colour change still can be observed but the colour produced more too light-yellow. So, we can observe that the more concentrated the starch solution, the more deep blue colour will produced. Materials 1.5% (w/v) starch solution Iodine Distilled water Glass pipets Test tubes Test tubes rack

Objective 1. To study the diluted starch concentration with distilled water in the presence of iodine. 2. To observed the colour of diluted starch concentration in the presence of iodine in 5 different test tubes. Methods 1. 9 ml of distilled water were placed in 5 test tubes by using the glass/serological pipets. 2. 1.0% (w/v) starch solution blue was took and added into the test tubes containing 9 ml of distilled water. The solution was mixed well and left it to settle down. Test tube was labelled as A. 3. 1 ml of test tube A was took and was transferred into the next test tubes that contained 9 ml of distilled water. The solution was mixed by using vortex instrument and left it to settle down. Test tube was labelled as B. 4. 1 ml of test tube B was took and was transferred into the next test tubes that contained 9 ml of distilled water. The solution was mixed using vortex instrument and left it to settle down. Test tube was labelled as C. 5. 1 ml of test tube C was took and was transferred into the next test tubes that contained 9 ml of distilled water. The solution was mixed by using vortex instrument and left it to settle down. Test tube was labelled as D. 6. 1 ml of test tube D was took and was transferred into the next test tube that contained 9 ml of distilled water. The solution was mixed by using vortex instrument and left it to settle down. Test tube was labelled as E. 7. The test tubes were heated at 80°C in the water bath for five minutes. Two drops of iodine solution were added into all test tubes and the observation was recorded and described. 8. The starch concentration and dilution factor of test tubes A to E were calculated.

Result Test Tube A B C D E

Starch Concentration(µg/ml)

Dilution Factor

10000 1000 100 10 1

1:10 1:100 1:1000 1:10000 1:100000

Observations

E

D

C

B

A : The colour of the mixture is blue-black

B : The colour of the mixture is blue

C : The colour of the mixture is light yellow

D : The colour of the mixture is light yellow

E: The colour of the mixture is light yellow

A

Discussion Dilution can be defined as the process where the concentration is the measure of how much of a given substances there is mixed with another substances. To concentrate a solution, the solute must be added to the solution or reduce the amount of solvent, in contrast, to dilute a solution, the solvent must be added to the solution or reduce the amount of solute. In this experiment, the dilution factor of the samples (distilled water which filled with starch in several tubes) and starch concentration are determined by using serial dilution method (use iodine solution as indicator). Iodine solution was used in this experiment as indicator because it has function which is detecting the presence of starch in sample. If starch detected in sample, the sample will turn in colour which from colourless to blue or yellow. The expected outcomes from this experiment are the test tube A, B, C, D and E have different colour after the iodine is added to the sample as shown in diagram 1.

Diagram 1

Sample in test tube A has the strongest colour (dark blue in colour) because the sample in test tube A has the highest concentration of starch and the following sample which are test tube B, C, D and E have lighter in colour which are light blue, purple, yellow and light yellow in colour respectively because the concentration of the starch in these test tube is decreased. Based on the result gained which is shown diagram 2, colour of test tube A has the strongest colour (dark blue in colour) as expected meanwhile the colour of sample in test tubes B, C and D have not showed any differences in term of colour between them (analyte in these test tubes have same colour which light yellow in colour).

Diagram 2 (test tube E, D, C, B and A) Although the colour of samples change and show different strength of the colour after the addition of iodine due to the present of solute (starch) and the different concentration of the solute in the sample, the result that obtained does not precise exactly with the hypothesis. The possible errors that may occurred while handle the experiment are the misused of pipette which can interfere while take the concentration of sample that needed. Next, contamination existed in the sample which can affect the outcomes of the experiment. The error and the lack of sensitivity of the apparatus also can affect the result of the experiment.

Conclusion Overall, the experiment succeeded in showing that dilution of starch concentration with distilled water in the presence of iodine gives different outcome from test tube A to E. Each samples show different colour which is in test tube A is mixture blue-black, test tube B is mixture of blue, test tube C,D,E is mixture of light-yellow. These differences, however, can be accounted for by experimental error.

Exercise 5:

You have 100 μl at a concentration of 7.22 mg/ml. From this material, you need to make 4 ml of a 50 μg/ml solution. To determine the amount of the expensive protein you need, use the formula:

C1 V 1 = C 2 V 2 , where V = volume and C = concentration.

Calculate volume of expensive protein needed in ml & μl to make up the solution and add it in to ml of buffer as stated below.

Then V1 = 0.1mL of expensive protein. To make the dilution, you would take 0.9ml ( 900μl) of the expensive protein solution and add it to 0.1ml of buffer to get a final volume of 4 ml.

Exercise 6

1.

Prepare 2 litres of a 0.2 M (0.2 mole/litre) solution of a chemical having a FW of

154.2 g/mole. How many grams of the chemical do I need to use?

2.

You have a 5 mg/ml solution of a protein with a molecular weight of 66,000. How

many moles/litre proteins are there in your solution?

Exercise 7

1.

0.9% (w/v) NaCl solution is 0.9g NaCl in 100ml water.

When the formula includes a liquid chemical, then the percent solution is volume added chemical in ml made up to 100 ml with solvent.

2.

10% (v/v) acetic acid solution in water is 10 ml glacial acetic acid added to 100 ml

water.

Exercise 8

1. We have 5.15 ml of a solution containing 1.973g/ml protein. How much total protein do we have? Total protein/5.15 ml = 1.973 g/ml Total protein = 1.973 g/ml × 5.15ml Total protein = 10.16 g (round off to the smallest significant value) 2. We have five results from an experiment: 2.6%, 2.4%, 2.5%, 2.3%, 2.4%. The average of these five measurements is %. Average of these five measurements = (2.6 + 2.4 +2.5 +2.3 +2.4)% /5 = 2.4 % (round off to the smallest significant value)

References Flinn

Scientific

(2017).

Preparation

of

Starch

solution.

https://www.flinnsci.ca/preparation-of-starch-solution. Biochemistry I Laboratory CHEM 4401 Units, Concentrations, Solutions and Dilution. (2013,January 28). Retrived from http://faculty.tamucc.edu/plarkin/4101folder/CHEM%204401%20L1%20Units.pdf Zinnen, Tom (June 2004), The Micropipette Story, retrieved November 12, 2011 Solution Concentration.(May 2005). Retrieved from https://courses.lumenlearning.com/boundless-chemistry/chapter/solution-concentration/...