Datasheet for Lab 4: Cellular Respiration and Photosynthesis in Plants

Transcription

1 Name Datasheet for Lab 4: Cellular Respiration and Photosynthesis in Plants Discuss your hypotheses and predictions from your prelab with your group. Revise them if necessary and record them in the tables below. Table 1: Hypothesis and Prediction for Plant in Light Hypothesis: Prediction: IF we expose spinach leaves to LIGHT conditions, THEN we expect LEVELS of to and LEVELS of to Table 2: Hypothesis and Prediction for Plant in Dark Hypothesis: Prediction: IF we expose spinach leaves to DARK conditions, THEN we expect LEVELS of to and LEVELS of to. Page 1 of 5

2 GRAPHS Darkness O2 Gas vs. Time CO2 Gas vs. Time Light O2 Gas vs. Time CO2 Gas vs. Time DATA Leaves In the dark In the light Table 3 O2 rate of production/consumption (ppt/s)= m value CO2 rate of production/consumption (ppt/s) = m value Page 2 of 5

3 INTERPRETING THE DATA AND DRAWING CONCLUSIONS Revisit the hypotheses and predictions you made in Tables 1 and 2. Using your data, answer the following questions: 1. Do you support or reject your hypothesis explaining the rates of photosynthesis and respiration occurring in the light? Explain your reasoning. If you reject your hypothesis, write a corrected hypothesis below. 2. Do you support or reject your hypothesis explaining the rates of photosynthesis and respiration occurring in the dark? Explain your reasoning. If you reject your hypothesis, write a corrected hypothesis below. Carbon sources are anything that release more carbon (typically in the form of CO2) then it absorbs. Carbon sinks are anything that absorbs more carbon than it releases essentially becoming a reservoir or storage area for the CO2. 3. Are plants a carbon SOURCE or SINK in light conditions? What evidence do you have for your answer? 4. Are plants a carbon SOURCE or SINK in dark conditions? What evidence do you have for your answer? 5. Plants are considered Net Producers, which means they produce more sugars during the day then they use during the day (over the course of their lifespan). Explain what this means in terms of cellular respiration, photosynthesis and the growth of the plant. 6. What factors can affect the rate of photosynthesis? Page 3 of 5

4 POSTLAB QUESTIONS : (Note: these questions may be worked on during the data collection time in lab) 8. Examine the image above (The Carbon Cycle). Now pick a real ecosystem that you are familiar with (can be your backyard, a local park, etc.) and make a diagram of the carbon cycle within this ecosystem. Include: at least two different examples of show where cellular respiration is occurring autotrophs (producers) show where photosynthesis is occurring at least two different examples of heterotrophs (consumers) show where decomposition is occurring at least one example of a decomposer 9. Examine the carbon cycle you drew above. a. Which process (photosynthesis or cellular respiration) is occurring during decomposition? b. List the processes that move carbon from one reservoir to another. Page 4 of 5

5 c. Are living organisms carbon sources, carbon sinks or both? d. Are producers net (overall) sources or sinks? e. Are consumers net (overall) sources or sinks? f. Note on your drawing where carbon is in its inorganic form (CO2) or organic forms (e.g., glucose, cellulose). Residence time is the time a substance (e.g., CO2, water) stays in a particular location or reservoir. g. Note on your drawing where residence time for carbon is short (hours to days) and where it is long (months to years). h. Where do you think residence time is the longest for carbon? 10. List at least three human activities that can increase the amount of CO2 in the atmosphere. 11. Use the information below to calculate how many trees (carbon sink) you would need to plant in order to offset the fossil fuel (carbon source) burnt in your car over a year. a) Calculate how many tonnes of CO2 are released annually by your driving by using this website: b) Convert the amount in tonnes to the amount in pounds using this converter: c) Use this calculator to determine how many trees with a circumference of between 120 and would be needed to balance that amount of carbon dioxide output. d) If you were having trees planted now to offset your carbon dioxide emissions from driving for one year, how many trees would that require and why? Page 5 of 5