PHOTOSYNTHESISEXERCISE 12 A & B Group 3Andal, Alliza De La Cruz, JairoDulnuan, DuchessFlorece, Kristine

PHOTOSYNTHESISPhotosynthesis is a redox reaction, wherein plants convert carbon dioxide and water to their own organic molecules and release oxygen as a by-product, summarized by the equation below:

ObjectiveTo determine the role of chlorophyll in photosynthesisTo determine the role of light in photosynthesis PHOTOSYNTHESIS

The Role of Chlorophyll in PhotosynthesisGraptophyllum pictum L.

The Role of ChlorophyllMethodology

Questions:What is the purpose of boiling the leaf prior to chlorophyll extraction?

What is the purpose of boiling the leaf in the ethyl alcohol?

The Role of Chlorophyll

Answers:The leaf was boiled to rupture the cell membrane and remove the cuticle in the epidermis.

The leaf was boiled in ethyl alcohol to bleach the green part containing the starch.

The Role of Chlorophyll

ResultThe Role of Chlorophyll

DiscussionThe presence of starch indicates the presence of the chlorophyll; thus, photosynthesis occurred. The Role of ChlorophyllConclusionThe blackening of the original green parts indicate the presence of starch in the leaf.

The Role of Light in PhotosynthesisPotted Phaseolus radiatus Linn. plant

The Role of LightMethodology

ResultThe covered part didnt appear to have starch when applied with IKI solution. The Role of Light

Questions:What is the purpose of putting the plants in the dark for 48 hours?

What portions in the leaf showed a positive reaction to starch test? The Role of LightDiscussion and Conclusion

Answers:The plant was put to dark so photosynthesis would not occur.

The uncovered part of the leaf exhibit the positive reaction to starch unlike the covered part which did not exhibit the presence of starch because there was no sunlight for photosynthesis to occur.The Role of LightDiscussion and Conclusion

The absence of starch in the covered part of the leaf indicates that photosynthesis did not occur in the area due to the absence of light; thus, light is a vital factor for photosynthesis to occur. The Role of LightDiscussion and Conclusion

Reference:Reece, J.B., 2011. Campbell Biology: Concepts & Connections. 7th Edition. Pearson Education Inc. Jurong, Singapore.