Introduction
S.6.3 - Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and the flow of energy into and out of organisms.
All organisms, even people, need energy to do complete the actions required for life. Whether you're playing a sport, studying for a test, or eating a meal, there are energy needs which must be fulfilled in order to make this happen. We eat food and process the food's nutrients to obtain energy, but what about plants? Most plants do not need to eat food in the same manner which provide animals with energy, so how do plants such as trees grow to such staggering heights without eating? In this lab, you'll learn the processes by which plants obtain and meet their energy needs, which in turn, provide the energy requirements which meet the needs of entire ecosystems.
Task
The task for today's lesson will be to perform the online lab for Photosynthesis and Cellular Respiration found within the Labxchange.org website. The lab includes a series of introductory readings with prediction questions attached where you must read and answer the comprehension questions and make predictions prior to conducting the virtual experiment. The experiment will demonstrate how pH changes as photosynthesis occurs by transferring water and carbon dioxide into sucrose and oxygen as a chemical reaction.
Your task will be to answer the provided questions, make the necessary predictions, conduct the virtual experiment, and draw conclusions with respect to your hypothesis. Your responses will be recorded in your lab journal as well. This will include the previously mentioned aspects of the lab and the empirical data measured by finding the pH of the solutions and the readings from the spectroscopy portion of the lab as well.
Process
1. Acquire your iPads and log into your school-based account.
2. Click on the following link to begin the lab: Photosynthesis and Cellular Respiration - LabXchange
3. Remember to annotate your responses to the questions into your lab journal and take pictures of your responses.
4. Answer the Evaluation questions after you have completed and post your responses to Schoology.
Evaluation
1. What are the primary reactants and products of photosynthesis?
2. Describe why the BTB solution exposed to light turned blue.
3. Describe why the BTB solution exposed to darkness turned yellow.
4. Explain your results with the spectroscopy portion of the lab. Did you notice any patterns between pH and absorbance?
5. Where does the majority of the mass of plants come from? Were you surprised by this conclusion?
Conclusion
Carbon dioxide and water are the two main components that facilitate plant growth and will eventually be the resultant factors which supply ecosystems. It has been shown that pH changes occur as a result of this chemical reaction where the transfer of hydrogen atoms from water combine with the carbon dioxide to form oxygen gas and sucrose. From the lab, we can also conclude that the Elodea plant growth that was witnessed showed a parabolic growth pattern over the course of the 'twelve hours' that it was surveyed and reacted to the BTB solution. Because of photosynthesis, plants are able to utilize carbon dioxide from the atmosphere where a greater density of vegitation can neutralize this powerful greenhouse gas.
Credits
Photosynthesis and cellular respiration. (2025). Retrieved from https://www.labxchange.org/library/items/lb:LabXchange:0cf2328b:lx_simu…