Visualizing Visualizing Biochemical Biochemical PathwaysPathways

Kali MacAdam and Ramie QaisarKali MacAdam and Ramie Qaisar

Table of ContentsTable of Contents1.1. Robert Emerson and William ArnoldRobert Emerson and William Arnold

2.2. Hans Gaffron and WahlHans Gaffron and Wahl

3.3. Prior KnowledgePrior Knowledge

4.4. The ExperimentThe Experiment

5.5. The ResultsThe Results

6.6. Interpretation of ResultsInterpretation of Results

Robert Emerson Robert Emerson and William and William

ArnoldArnold• Plant Physiologist born on Plant Physiologist born on

November 4November 4thth, 1903; died , 1903; died February 4February 4thth 1959. 1959.

• Studied under Otto Warburg in Studied under Otto Warburg in Berlin in 1927.Berlin in 1927.

• Joined Cal Tech in 1930.Joined Cal Tech in 1930.

• Worked with undergraduate Worked with undergraduate student William Arnoldstudent William Arnold

Hans Gaffron and Hans Gaffron and WahlWahl

• Chemist and Chemist and Biological Researcher Biological Researcher born May 17, 1902 born May 17, 1902 and died August 18, and died August 18, 1979.1979.

• Studied and Studied and developed many developed many theories with Wahl theories with Wahl throughout the 20throughout the 20thth century.century.

Prior KnowledgePrior KnowledgeOxygen in photosynthesis is produced by the Oxygen in photosynthesis is produced by the splitting of water, not by splitting carbon splitting of water, not by splitting carbon dioxide.dioxide.Proved by C.B. Van Neil in the early 1930s using Proved by C.B. Van Neil in the early 1930s using the purple sulfur bacteria experiment:the purple sulfur bacteria experiment:COCO22 + 2H + 2H22S + light S + light [CH [CH22O] + HO] + H22O + 2SO + 2S““the yield of photosynthesis in alternating light the yield of photosynthesis in alternating light with equal light and dark periods, and showed with equal light and dark periods, and showed that very short dark periods can contribute to that very short dark periods can contribute to photosynthesis almost as much as equal periods photosynthesis almost as much as equal periods of illumination” (Rabinowitch, 181)of illumination” (Rabinowitch, 181)Quantum Theory: Light comes in bursts called Quantum Theory: Light comes in bursts called quanta quanta

The ExperimentThe Experiment

Slight Change from Otto Warburg’s Slight Change from Otto Warburg’s designdesign

Plant: Green Algae Plant: Green Algae

Light from condenser discharges Light from condenser discharges

““On” period: 10On” period: 10-5-5 seconds seconds

““Off” period: 0.1 secondsOff” period: 0.1 seconds

ResultsResultsWahl and Gaffron calculated a ratio Wahl and Gaffron calculated a ratio between CObetween CO22 and Chlorophyll molecules. and Chlorophyll molecules.

This ratio was found to be constant This ratio was found to be constant during the alternating dark and light during the alternating dark and light periods as well as periods continuous periods as well as periods continuous light.light.

Interpretation of Interpretation of ResultsResults

For 1 molecule of OFor 1 molecule of O2 2 produced, 2400 chlorophyll produced, 2400 chlorophyll molecules are present.molecules are present.

Creation of a “unit” was suggestedCreation of a “unit” was suggested

Gaffron and Wohl, developed on Emerson and Gaffron and Wohl, developed on Emerson and Arnold’s findings.Arnold’s findings.

““light absorbed by most of the chlorophyll molecules light absorbed by most of the chlorophyll molecules in the ‘photosynthetic unit’ is transferred to the in the ‘photosynthetic unit’ is transferred to the ‘photoenzyme’ for chemistry..” (Rabinowitch,1932)‘photoenzyme’ for chemistry..” (Rabinowitch,1932)

““Off time” allows time for the photosynthetic Off time” allows time for the photosynthetic reactions to occurreactions to occur

Quantum theory relation Quantum theory relation

Sources UsedSources UsedRobert Emerson, 1903 – 1959 Robert Emerson, 1903 – 1959

http://www.linkpdf.com/ebook-viewer.php?http://www.linkpdf.com/ebook-viewer.php?url=http://books.nap.edu/html/biomems/url=http://books.nap.edu/html/biomems/remerson35.pdfremerson35.pdf

Emerson, Robert Emerson, Robert http://www.encyclopedia.com/doc/1G2-http://www.encyclopedia.com/doc/1G2-2830901315.html2830901315.html

JSTOR: Plant Physiology, JSTOR: Plant Physiology, http://www.jstor.org/pss/4257438http://www.jstor.org/pss/4257438

Milestones in Photosynthesis Research Milestones in Photosynthesis Research http://www.life.illinois.edu/govindjee/papers/milestonhttp://www.life.illinois.edu/govindjee/papers/milestones.htmles.html