Tuesday, April 19th - Photosynthesis and homework

(summary of what we did in class today is below the homework)

HOMEWORK IS DUE ON BLOCK DAY:

Read the information about the photosynthesis lab at the link below then answer the 6 questions written below.

http://www.phschool.com/science/biology_place/labbench/lab4/concepts2.html

Explain each of these in your own words.  Do not copy responses directly from the simulation.

1. What is the function of DPIP in this experiment?

2. What does a spectrophotometer measure AND why do we use a spectrophotometer rather than just collecting this data visually?

3.  Predict what we will see happening to the % transmittance in each of the 4 tubes (increase in tranmittance, decrease in transmittance or transmittance will stay the same) and explain.
     Tube 1: No DPIP, unboiled chloroplasts
     Tube 2: DPIP, unboiled chloroplasts
     Tube 3: DPIP, unboiled chloroplasts, wrapped in foil
     Tube 4: DPIP, boiled chloroplasts

4. Analyze the data in the table below. 

 Transmittance (%)                                      Time (min.)

Cuvette	0	5	10	15
2 Unboiled/Dark	31	34	35	36
3 Unboiled/Light	33	47	58	60
4 Boiled/Light	32	33	32	32
5 No Chloroplasts	31	31	31	31

5. In the following sample data table explain what most likely went wrong to give us this data.  (only include explanation that would give THIS particular set of data)

A) Describe the trends seen and

B) Explain why we see these trends.

                        Transmittance (%)                            Time (min.)

Cuvette	0	5	10	15
2 Unboiled/Dark	31	34	35	36
3 Unboiled/Light	33	47	58	60
4 Boiled/Light	32	45	55	58
5 No Chloroplasts	31	31	31	31

6.  In the following sample data table explain what most likely went wrong to give us this data.  (only include explanation that would give THIS particular set of data)

Transmittance (%)                            Time (min.)

Cuvette	0	5	10	15
2 Unboiled/Dark	31	39	45	50
3 Unboiled/Light	33	47	58	60
4 Boiled/Light	32	33	32	32
5 No Chloroplasts	31	31	31	31

In class today we continued our conversation about photosynthesis.  This information can also be found in chapter 10 of your text.  We started with a big picture of how light is used to make sugar in the chloroplasts and then focused in on the light-dependent reactions.