1. By: Jan Villamor Anna- Maria Allen Amanda Brennan
The discovery of The Chloroplast Julius Von Sachs & Theodore Wilhelm Engelmann
By: Jan Villamor
Anna- Maria Allen
Amanda Brennan

2. Previous Knowledge Phototropism Plants take in CO₂ and produce O₂
(from the discoveries of F.F Blackman, Van Helmot, and Jan Ingenhousz)

3. Julius Von Sachs (1832-1897) A German botanist
Fouder of experimental plant physiology
Discovered that photosynthesis occurred in the chloroplast
Found out that starch is present in chloroplasts by using the Iodine test
It is thanks to him that we have the Iodine test that we use
today
Had a great influence on British and American Botany

4. Major experiments Grew plants in water instead of soil
As a result, it demonstrated that plants can grow with just water, the right amount of nutrients and sunlight
He used the Iodine test to show that carbon was first accumulated as starch in the leaves of plants
Learned that chlorophyll, light and CO₂ are necessary for carbon fixation - carbon fixation is the first stage of the dark reaction of photosynthesis

5. Theodore Wilhelm Engelmann (1843-1903)
A German botanist, physiologist, microbiologist, university professor, and musician
Showed that the light reactions of photosynthesis is converted into chemical energy within the choloroplast
Aim was to discover which part of the cell functioned as light receptors

6. Major Experiments
Used a modified microscope that was able to distinguish and measure different wavelengths of light
Measured the different wavelengths of light on photosynthetic activity
Conducted an experiment that involved illuminating a filamentous alga called Spiragoya (a form of green algae commonly found in freshwater ponds and ditches).
-Light was passed through a prism, exposing all the parts of
the spiragoya in different wavelengths
- aerobic bacteria were used to locate where the alga was
releasing the most oxygen
- the bacteria clumped under the red and blue light

7. Experiment Findings
Proved that photosynthesis takes place inside the chloroplasts of plants
Photosynthesis is necessary in order for plants to survive
Chloroplasts receive the most energy from red and blue light more than any other colour in the spectrum. A year later, Engelmann discovered that purple bacteria used UV light in the same way

8. Link:
Basics of the Chloroplast

9. References:
1) "Julius von Sachs Facts, information, pictures | Encyclopedia.com articles about Julius von Sachs." Encyclopedia - Online Dictionary | Encyclopedia.com: Get facts, articles, pictures, video. N.p., n.d. Web. 13 Nov <
2) Nair, Sonia. "What is Spirogyra." Buzzle Web Portal: Intelligent Life on the Web. N.p., n.d. Web. 14 Nov <
3) "Theodor Wilhelm Engelmann - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 14 Nov <