Experiment 9 Report Sheet SOLVING A MURDER MYSTERY USING TRANSITION METALS AND D

Question

Experiment 9 Report Sheet

SOLVING A MURDER MYSTERY USING TRANSITION METALS AND DNA

Total Points =

  Total  

55

Experimental Procedure

1. Obtain 6 test tubes and label them: no-DNA control, Arnold (A), Cindy (C), Gary (G), Tina (T), and Knife (unknown).

2. Use the syringe to add solutions to each test tube. When using the syringe, be careful to clean between each different chemical added. Clean the syringe by drawing distilled water into the syringe and expelling it out into the sink. Do this 5 times between each different chemical that will be measured by the syringe. Before placing the syringe into a new solution, wipe the outside of the syringe with a paper towel.

3. Add the following amounts of each chemical to each test tube. First add water, then the buffer solution, then the DNA solution. Mix the solutions with a transfer pipet.

Test Tube

Distilled H2O (mL)

DNA / Buffer (mL)

0.01 M KMnO4 (mL)

1 (No-DNA Control)

1.5

3.5

0.5

2 (Arnold)

1.5

3.5

0.5

3 (Cindy)

1.5

3.5

0.5

4 (Gary)

1.5

3.5

0.5

5 (Tina)

1.5

3.5

0.5

6 (Knife Handle)

1.5

3.5

0.5

4. Add 0.5 mL of the 0.01 M potassium permanganate solution to each of the test tubes and mix the solutions thoroughly using a transfer pipet.

5. Observe the solutions and write down your observations over a 20 minute time frame.

NG

8

6. At 20 minutes, document your experiment by taking one picture that contains all six samples. Place a piece of white paper behind the samples to get the clearest colors in your picture. A color print of your picture must be added to your final lab report.

To upload the picture:

Take the picture with your phone

After your lab attendance has been set, use your phone to log on to chem21Labs.com and navigate to this webpage

Click the Upload Image link and Browse on your phone until you see the picture.

Select the picture and complete the upload.

OR

Take the picture with your phone

Email the picture to yourself

Save the picture to your computer's harddrive

Follow the steps above to upload the image from your computer

NG

6

Discussion Questions

1. What is the purpose of the control test tube? What does it tell you about the experiment in general?

NG

8

Edit Answer

2. For each of the six reactions, what color did you observe at the 20 minute time point? At the 20 minute time point, what is the most likely oxidation state of manganese in each of the 6 reactions?

NG

6

Edit Answer

3. In this experiment, what is being reduced, and what is being oxidized?

NG

6

Edit Answer

4. What is the reducing agent, and what is the oxidizing agent?

NG

7

5. Which DNA nucleotide is the strongest reducing agent, and which is the weakest?

NG

6

6. Who is the most likely murderer in your experiment?

NG

8

Edit Answer

Total Points =

  Total  

55

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Experiment 9 Report Sheet

SOLVING A MURDER MYSTERY USING TRANSITION METALS AND DNA

Total Points =

  Total  

55

Experimental Procedure

1. Obtain 6 test tubes and label them: no-DNA control, Arnold (A), Cindy (C), Gary (G), Tina (T), and Knife (unknown).

2. Use the syringe to add solutions to each test tube. When using the syringe, be careful to clean between each different chemical added. Clean the syringe by drawing distilled water into the syringe and expelling it out into the sink. Do this 5 times between each different chemical that will be measured by the syringe. Before placing the syringe into a new solution, wipe the outside of the syringe with a paper towel.

3. Add the following amounts of each chemical to each test tube. First add water, then the buffer solution, then the DNA solution. Mix the solutions with a transfer pipet.

Test Tube

Distilled H2O (mL)

DNA / Buffer (mL)

0.01 M KMnO4 (mL)

1 (No-DNA Control)

1.5

3.5

0.5

2 (Arnold)

1.5

3.5

0.5

3 (Cindy)

1.5

3.5

0.5

4 (Gary)

1.5

3.5

0.5

5 (Tina)

1.5

3.5

0.5

6 (Knife Handle)

1.5

3.5

0.5

4. Add 0.5 mL of the 0.01 M potassium permanganate solution to each of the test tubes and mix the solutions thoroughly using a transfer pipet.

5. Observe the solutions and write down your observations over a 20 minute time frame.

NG

8

6. At 20 minutes, document your experiment by taking one picture that contains all six samples. Place a piece of white paper behind the samples to get the clearest colors in your picture. A color print of your picture must be added to your final lab report.

To upload the picture:

Take the picture with your phone

After your lab attendance has been set, use your phone to log on to chem21Labs.com and navigate to this webpage

Click the Upload Image link and Browse on your phone until you see the picture.

Select the picture and complete the upload.

OR

Take the picture with your phone

Email the picture to yourself

Save the picture to your computer's harddrive

Follow the steps above to upload the image from your computer

Edit Answer

NG

6

Discussion Questions

1. What is the purpose of the control test tube? What does it tell you about the experiment in general?

NG

8

Edit Answer

2. For each of the six reactions, what color did you observe at the 20 minute time point? At the 20 minute time point, what is the most likely oxidation state of manganese in each of the 6 reactions?

NG

6

Edit Answer

3. In this experiment, what is being reduced, and what is being oxidized?

NG

6

Edit Answer

4. What is the reducing agent, and what is the oxidizing agent?

NG

7

Edit Answer

5. Which DNA nucleotide is the strongest reducing agent, and which is the weakest?

NG

6

Edit Answer

6. Who is the most likely murderer in your experiment?

NG

8

Edit Answer

Total Points =

  Total  

55

Explanation / Answer

1. The purpose of control test tube is for baseline measure. It is to analyse the effect of reactions between chemical reagents except the variable sample used for experiment. It is needed to tear the response of reagents while analyzing sample as they are interfering with true results of reaction. In the particular experiment the role of control is to determine the color change in solution in the absence of DNA.

2. The experiment is started with potassium permanganate (KMnO4) solutions, oxidation state of Mn is = +7, The starting solutions will be purple. After addition of DNA samples to the KMnO4 solutions, the DNA samples will reduce the Mn and change its oxidation state and color of each solution also change. Different DNA samples will cause the KMnO4 to undergo reduction to different extents. Actually in DNA Thymine and cytosine bases are good reducing agents Therefore,KMnO4 with the DNA the reaction mixture goes from a purple solution (+7) to a yellow intermediate
(+5) and finally to clear or with brown precipitate MnO2 (+4) .

(3) The starting reagent KMnO4 has oxidation state +7. In the reaction the oxidation state of manganese is decreasing till +4 and therefore manganese is undergoing reduction. The reaction takes place in presence of DNA nitrogenous base specifically Thymine and cytosine. They are then undergoing oxidation.

(4) Nitrogenous bases of DNA Thymine and cytosine are reducing agents that induce the reduction of KMnO4. And KMnO4 is the oxidizing agent that induce the oxidation of DNA bases by reducing (accepting electrons) itself.

(5)  Thymine and cytosine are good reducing agents for the reduction reaction of KMnO4,  while adenine and guanine are not.

(6) Need to know the observations of experiment to reach at the conclusion of murderer's name.

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