Exploring Photosynthesis Worksheet-2 PDF

Preview

Summary

Download Exploring Photosynthesis Worksheet-2 PDF

Description

Online students: upload this worksheet to a shared drive (i.e. OneDrive, Google Docs or a similar resource) and work together with your online groupmates to complete it while your in-person counterparts set up the experiment. If your group is done and other students are still conducting their experiments, discuss the completed worksheet with in-person students; otherwise, in-person students can review it after the lab period ends. Questions included on this worksheet may appear on your final lab exam – make sure to answer each to the best of your ability! 1. Explain the difference between Photosystems I and II. What kind of reactions occur in each?. a. Both Photosystem I and II contain several pigments that assist in collecting light energy. The chlorophyll molecules in Photosystem I are P700, while the ones in Photosystem II are P680. In photosystem I, NADPH synthesis occurs, and the electrons from PS II are received. In photosystem II, hydrolysis of water occurs, as well as ATP synthesis.

2. Compare and contrast thylakoid membranes and mitochondria. Note structural and functional differences/similarities. a. Thylakoid membrane contains carotenoids, chlorophyll, and pigments, while the mitochondria does not contain any pigments. The thylakoid membrane conducts the light reactions of photosynthesis. The mitochondria is a membrane bound organelle found in most eukaryotic cells. 3. Would anything happen if you didn’t use a heat sink for this experiment? i.e., would excess heat affect unboiled chloroplasts? Hint: it may be helpful to revisit temperature optima information from the enzymes lab. a. Yes, the enzymes would not show maximum activity since they are not at their optimal temperature, which ranges from 20-40C and if the temperature is too high from their optimal range it could denature them and would not allow them to catalyze their reaction. Excess heat would affect the unboiled chloroplasts because it would denature them and they would not function correctly and they would lose their overall shape. 4. How many types of chlorophyll are there? List them and provide an example of the organisms they’re found in for each.  of chlorophyll: chlorophyll a, found in all higher plants, algae a. There are four types and cyanobacteria; chlorophyll b, found in higher plants and green algae; chlorophyll c, found in diatoms, dinoflagellates and brown algae; and chlorophyll  d, found only in red algae.

5. Why are stomata important? What role do guard cells play in their function?

a. Stomata have two main functions, namely they allow for gas exchange acting as an entryway for carbon dioxide (CO2) and releasing the Oxygen   (O2) that we breath. The other main function is regulating water movement through transpiration.Guard  cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the  stomata. 6. We talked about concentration gradients earlier this semester (e.g. in the Diffusion and Osmosis lab) – how do they relate to photosynthesis? Why is maintaining a concentration gradient specifically important for energy production? Note: the use of concentration gradients by cells to accomplish specific functions will be revisited in many other courses (e.g. neuroscience, anatomy, etc.), so it’s important to understand this concept. a. Concentration gradients relate to photosynthesis since during the electron movement a H+ ion concentration gradient is produced across the thylakoid membrane. This is similar to what happens in the mitochondria during cellular respiration, the H+ is allowed to diffuse back across the membrane and into the stroma due to the facilitation of the ATP synthase enzyme. It is important to maintain this concentration gradient for energy production since the H+ flow is what powers the pump and ATP is the result that is produced....