Objective Chlamy Results and Figures The objective for Experiment 1 was to evaluate the photosynthetic efficiency of Chlamydomonas reinhardtii chlamy by assessing the rate of oxygen production under specific metabolic conditions The aim was to understand how photosystem II PSII activity and mitochondrial electron transport contribute to oxygen levels in a controlled environment Two metabolic inhibitors were introduced DCMU which blocks PSII and sodium azide which targets mitochondrial respiration to observe the effects of each pathway on oxygen production This experimental setup allowed us to quantify the change in oxygen levels in response to the two inhibitors Measuring these oxygen levels under normal and then inhibited conditions showcases the relationship between photosynthetic and respiratory activities within chlamy thus addressing the primary objective of determining how each metabolic pathway influences oxygen levels Investigating the motility of chlamy cells when exposed to metabolic poisons which disrupts ATP production essential for cellular movement was the purpose of Experiment 2 By examining how chlamy cells respond to these treatments this experiment delved into how metabolic energy derived from photosynthesis and respiration affects motility In this setup cells were exposed to light for a designated period to stimulate cell movement with conditions carefully controlled to distinguish the effects on cell distribution across the tray The concentration of motile cells was then assessed using a hemocytometer allowing us to infer the relationship between energy disruptions and chlamy s kinetic behavior Methodology In Experiment 1 chlamy cultures were exposed to light for a set period under three experimental conditions untreated PSII inhibition with DCMU and mitochondrial inhibition with sodium azide Oxygen levels were monitored using a oxygen sensitive electrode which provided voltage readings proportional to oxygen concentration in the solution Cultures were exposed to a light source for a fixed duration to stimulate photosynthesis Voltage changes over time were recorded and analyzed as a relative measure of oxygen concentration under each condition The same three set of conditions were utilized to investigate cell motility untreated DCMU sodium azide After light exposure cell distribution was checked with a swim test where cultures were allowed to settle under controlled conditions Samples were then collected from the bottom at different regions of the culture tray light covered end middle and foil covered end and stained with iodine to immobilize the cells Cell concentration was then determined using a hemocytometer Results Voltage measurements over time for each condition are displayed in Figure 1 In the untreated sample voltage decreased steadily over the experimental period reflecting an increase in oxygen concentration because of active photosynthesis Photosynthetic activity proceeds normally where oxygen production from PSII exceeds oxygen consumption by respiration In the DCMU treated sample voltage indicated a moderate increase over time which reflects reduced oxygen production due to PSII inhibition as DCMU blocks the light dependent reactions of photosynthesis This observed increase in voltage suggests that respiration continues to consume residual oxygen in the solution and there is a net decrease in oxygen levels over time The sodium azide treated sample showed a slight decrease in voltage over time though the change was less pronounced than in the untreated sample Sodium azide inhibits respiration reducing oxygen consumption by the electron transport chain This allows photosynthetically generated oxygen to accumulate though it is at a slower rate compared to the untreated sample Figure 1 A graph displaying the voltage measurements over time for the three experimented conditions Underneath each line presents its own respective linear equation and R2 value The results for the swim test see figure 2 show distinct patterns in cell concentration under different conditions In the untreated samples the foil covered region exhibited the highest cell concentration 1 440 000 cells mL indicating that cells were largely nonmotile in the absence of light where ATP production from photosynthesis was not possible The light exposed region showed the second highest cell concentration 800 000 cells mL reflecting a mix of motile and nonmotile cells in optimal light conditions The middle region displayed the lowest cell concentration 560 000 cells mL suggesting greater movement and redistribution of cells in this middle area In the DCMU treated samples cell concentrations at the bottom of the foil covered regions were the lowest 80 000 cells mL indicating that most cells had swum upward despite the absence of light The light exposed region was 320 000 cells mL and the middle region showed a slightly higher concentration 360 000 cells mL consistent with a partial reduction in motility due to impaired ATP production for PSII inhibition For the azide treated samples in the light exposed region the concentration 540 000 cells mL suggested that the overall energy availability was reduced due to the lack of mitochondrial respiration In the middle region the concentration was slightly lower 460 000 cells mL In contrast the foil covered region exhibited the lowest concentration 50 000 cells mL indicating that most cells swam upward in the absence of light despite limited ATP production from respiration Figure 2 A table showcasing the cell concentrations of the varying samples after the swim test Sample Cell Concentration from the Bottom of the Tray cells mL Control Light Azide Light Untreated Light DCMU Middle Azide Middle Untreated Middle DCMU Foil Azide Foil Untreated Foil DCMU 640000 540000 800000 320000 460000 560000 360000 50000 1440000 80000
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