Lab #4:  Adirondack Leaf Pigments

 

Part 1:  Pre-lab Challenge Questions (LE textbook pages 136-137):

 

1)    What is light made up of ? (Paragraphs 1 and 2)

 

 

 

 

 

 

2)    Explain why leaves are green in the summer (Paragraph 3)

 

 

 

 

 

 

3)    Why do leaves change color in the fall (Paragraph 4)

 

 

 

 

 

 

 

 

After a lesson on photosynthesis answer the following challenge question using information on pages 139-140 of the LE textbook.

 

4)    What abiotic factors affect photosynthesis? (see The Rate of Photosynthesis)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Lab #3:  Adirondack Leaf Pigments

 

Following a lesson on proteins, pigments, and enzymes you will be given the following challenge to be worked on throughout the remainder of the first marking period.  Although we will be working together on this project Ð each student must hand in his/her own unique finished product for a major grade.

 

Part 2:  Adirondack Leaf Pigment Challenge

 

Your team will conduct a study of leaf pigment concentrations over a two month period.  Analyze data and create a poster, paper, or PowerPoint presentation displaying your results.  Based on your results you will create a new hypothesis to test.  Then you will design a controlled experiment to test your hypothesis.

 

5)    Before coming up with a hypothesis to test we must find out what happens to leaf pigment concentrations over time.  In order to do this we will be collecting leaf samples from now until the leaves begin to fall to the ground.  The tree to be studied is a sugar maple (Acer saccharum).  Throughout the time that we take leaf samples the physical environment will be changing.  What are some of those changes and how can we measure them?

 

Abiotic factor to be monitored

Procedure

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2)

 

 

 

 

 

3)

 

 

 

 

 

 

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Leaf sampling procedure for each time point:

 


  1. Use a whole punch to collect 2 leaf sections from 6 different leaves.  Be sure to choose leaves from each side of the tree to get a sample that represents the entire tree not just one side.

 

  1. Store  sections in two ziplock bags in the freezer

¯    both should be labeled with the date

¯    one should be labeled chlorophyll extraction and one anthocyanin extraction

 

  1. Samples will be gathered once a week on the same day and at the same time.

 

 

 

 

 

Pigment extraction procedures:

 

  1. Chlorophyll / carotenoid extraction

¯    Add 3 ml (80%) acetone to a test tube labeled chlorophyll with the date of the sample

¯    Store in the fridge (4¡C) overnight

 

  1. Anthocyanin extraction

¯    Add 3 ml (HCL:H2O:MeOH) 1:3:16

¯    Store in fridge overnight

 

  1. After  24 hours spin down using a centrifuge at high speed
  2. Measure absorption using a spectrophotometer

¯    A470 = Chlorophyll a

¯    A647 = Chlorophyll b

¯    A663 = Carotenoids

¯    A530 = Anthocyanin (methanol extractions)

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Lab #3:  Adirondack Leaf Pigments

Part 3:  Mini Challenges

 

6)    What is the economic importance of sugar maples in NYS? (Sugar Maple and Life of a sugar maple handouts)

 

 

 

 

 

 

 

7)    Describe the absorption spectrum for chlorophyll (LE text page 136-37)

 

 

 

 

 

 

 

 

8)    Name 3 types of pigments and their colors.  (Fantastic Fall Colors handout)

 

 

 

 

 

 

 

9)    Explain the ecological importance of sugar maples in the Adirondacks.

 

 

 

 

 

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 Product Quality Checklist

Challenge: Adirondack Leaf Pigment Challenge

 

Student:

Due Date:                                                                           Class Period:       

Observed

Standard/Criteria

Points Possible

Rating

 

Title:  centered, stands out, includes authorÕs name

5

     

 

Abstract: brief statement of purpose and hypothesis

5

     

 

Background Information:

     

     

 

     Ecological Importance of sugar maples in the Adirondacks

4

     

 

     Economic importance                  "

 2  

     

 

     Describes the spectrum of light

2

     

 

     Fully explain photosynthesis and the role of pigments

5

     

 

     A statement describing pigments as proteins and an explanation of the role of enzymes in their production

2

     

 

     A list of abiotic factors that might affect pigment production

5

     

 

Materials and Methods

     

     

 

     Includes all materials within the procedures

2

     

 

     Describe how samples were taken, prepared, and analyzed

4

 

 

     Describes how abiotic factors were monitored

2

 

 

     Provides enough detail to repeat the challenge

2

 

 

Results:

----Statement and line graph describing pigment concentrations over time

----Statement and graph describing changes in each of the abiotic factors studied

20

 

 

Conclusions:

----Describe the relationships between pigments and all of the abiotic factors

----Explain why a controlled experiment testing only 1 variable is necessary to better answer the essential question

----Formulate a new hypothesis based on your results

20

 

 

Sections are separated and clearly identified neatly

5

 

 

Student worked well and actively participated throughout the learning process

10

 

 

Assignment is handed in on time

5

 

 

 

 

 

 

TOTALS 100

     





 

Comments:      In addition to the above project.  Students will be expected to design a controlled experiment isolating one of the variables analyzed in this challenge.  Rubric for this portion of the challenge will be a predefined set of criteria established by the teacher in the beginning of the year.

 

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