Biology 210 Lab

Biology 210 Lab

Introduction
Today, your class would have conducted an experiment to examine if catechol oxidase is present or absent in apples, pears, and sweet potatoes. The experimental design should be complete to the extent that others can perform the experiment based solely on this information. Next week, you will revise the experimental design as needed. During the subsequent lab periods (at home), you will write a complete scientific paper draft (A8) over your experimental design using data from previous semesters, peer review your classmate’s drafts (A9), and revise the scientific paper you will write over this experiment (A10). This experimental design (A7) is worth 6 points. Your lab instructor will have specific directions on how to earn these points.

Use Exercise 4.1 (Action of Catechol Oxidase on p. 84-87) and the quantitative method outlined on p. 103 (Investigative Extensions #3) to construct an experiment for the class to perform (see Fig. 1 and Fig. 2 below). You should select a question, construct a hypothesis, and design an experiment to test the hypothesis. Each student will submit a copy of their experimental design to the lab instructor by Thursday April 9th, 2020.

Figure 1. Information regarding the action of catechol oxidase from Exercise 4.1.

Figure 2. Investigative extension #3.

Materials used for experiment:
Spectrophotometer

Test tube rack

8 quartz cuvettes

4 – 50 mL beakers

Pipette Pumps

Kimwipes

Sharpie %Transmittance→Absorbance conversion table

1 % Catechol

Potato, apple, pear, and sweet potato extracts

pH 7 buffer

Test tube rack and thermometer for room temperature incubation

Parafilm

Masking Tape

1 mL and 5mL glass pipettes

Disposable, uncalibrated transfer pipettes

Experimental Design
Based on the above information, come up with your own question for this experiment. Answer questions 1-8. Question 10 asks for an outline of the materials and methods section; you may type this up on a separate document and attach it as part of your assignment. Question 11 needs to be changed from “X, Y, Z” to the proper treatment levels you answered in Question 8. Use the data provided in question 12 to answer Question 13.

1. A statement of the question being asked (0.5 pts)
2. A statement of the hypothesis (0.5 pts)
3. A statement of the prediction (0.5 pts)
4. Independent variable (0.5 pts)
5. Dependent variable (0.5 pts)
6. Controlled variables (0.5 pts)

Note: Remember that each test tube must contain the same total volume (6 mL total) for quantitative comparisons. How will you maintain this constant volume?

1. Control (0.5 pts)
2. Levels of treatment (3) – list out treatment levels (0.5 pts)
3. Experimental replications = 7 total
4. Outline of the experimental methods section for your paper. Use this information and information from the PowerPoint over Cellular Respiration and Fermentation to write up the materials and methods section of your rough draft. Refer to Figure 2. Investigative extensions #3 for the format of the outline. If needed, write it in a separate document and include it with your submission. (1 pt)

A. Spectrophotometer calibration

· Spec 20 D+ Emulation

· 540 nm

· 100 % transmittance

B. Practice Round

· Test tube prep (parafilm/kimwipe)

· Don’t add catechol until ready!

· 5 min interval for 10 min

· Clean test tubes

C. Experimental Round

· Test tube prep (parafilm/kimwipe)

· Don’t add catechol until ready!

· 5 min interval for 20 min

· Clean test tubes

D. Record Data

· Data conversion form (%T -> A)

· Calculations

1. Table of test tube contents for blank tube(s), control tube, and tubes for each treatment level. This table may be used in your rough draft to show how the test tubes were filled out. Make sure you know what the X, Y, and Z placeholders are for and adjust the table accordingly.

Table 1.1. Contents of practice/experimental, blank and control test tubes

Test Tube

Extract

Catechol

pH 7 Buffer

Control (Potato Extract)

0.5 mL Potato

0.5 mL

5 mL

Apple Experimental Tube

0.5 mL apple

0.5 mL

5 mL

Pear Experimental Tube

0.5 mL pear

0.5 mL

5 mL

Sweet Potato Experimental Tube

0.5 mL sweet potato

0.5 mL

5 mL

Apple Blank

0.5 mL X Extract

0 mL

5.5 mL

Pear Blank

0.5 mL Y Extract

0 mL

5.5 mL

Sweet Potato Blank

0.5 mL Z Extract

0 mL

5.5 mL

Potato Blank

0.5 mL Potato

0 mL

5.5 mL

1. Table for inputting absorbance values. Use this data to create a graph for question 13.

Table 2.2. Absorbance values for experimental and control tubes over a 20-minute period.

Test Tube

Group

0 Minutes

5 Minutes

10 Minutes

15 Minutes

20 Minutes

Apple Extract

1

0

0.1534

0.1643

0.1659

0.1472

Apple Extract

2

0.0269

0.1871

0.2596

0.1308

0.0862

Apple Extract

3

0

0.0888

0.1382

0.1888

0.1855

Apple Extract

4

0.0132

1.301

0.1192

0.1024

0.1192

Apple Extract

5

0.2441

0.2291

0.2596

0.284

0.328

Apple Extract

6

0.2756

0.357

0.2291

0.2441

0.2675

Apple Extract

7

0.0362

0.1871

0.1871

0.2441

0.2147

Apple Extract (Average)

NA

0.085143

0.3576429

0.193871

0.1943

0.19261429

Pear Extract

1

0.02

0.1024

0.1707

0.1221

0.2403

Pear Extract

2

0.0458

0.2147

0.1939

0.1939

0.319

Pear Extract

3

0

0.0835

0.0888

0.0942

0.1235

Pear Extract

4

0.1675

0.2756

0.2291

0.1939

0.1739

Pear Extract

5

1.155

0.2756

0.2596

0.319

0.398

Pear Extract

6

0.2596

0.2007

0.0862

0.1303

0.2147

Pear Extract

7

0.0362

0.1739

0.2756

0.337

0.328

Pear Extract (Average)

NA

0.240586

0.1894857

0.186271

0.1986286

0.25677143

Sweet Potato Extract

1

0.0022

0.538

0.549

0.763

0.498

Sweet Potato Extract

2

0.0706

0.1612

0.2676

0.1192

0.1367

Sweet Potato Extract

3

0

0.6888

1.155

1.398

2

Sweet Potato Extract

4

0.2007

0

0

0

0

Sweet Potato Extract

5

2

0.721

1

2

0.959

Sweet Potato Extract

6

0.0706

0

0.0458

0.1192

0

Sweet Potato Extract

7

0

0.0555

0.0862

0.0757

0.0655

Sweet Potato Extract (Average)

NA

0.334871

0.3092143

0.443371

0.6393

0.52274286

Control (Potato Extract)

1

0.0281

0.959

0.2861

0.824

0.912

Control (Potato Extract)

2

0.0862

0.398

0.319

0.367

0.482

Control (Potato Extract)

3

0.2255

0.824

0.733

0.62

1.14

Control (Potato Extract)

4

0.409

0.432

0.387

0.398

0.42

Control (Potato Extract)

5

0.921

0.721

0.1939

1.046

1.398

Control (Potato Extract)

6

0.0088

0.2147

0.638

0.699

0.796

Control (Potato Extract)

7

0.2756

0.638

0.921

0.886

0.959

Control (Average)

NA

0.279171

0.5981

0.496857

0.6914286

0.87242857

1. Graph relating the average change in absorbance to time. Make sure to properly title and label the graph. You may create the graph by hand or use Excel. (One line for control tube, one line for each treatment level) (1 pt)