STUDENT LABORATORY Plant Respiration and Photosynthesis

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Hilary Bates
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1 Pasco Plant Respiration and Photosynthesis Page 1 of 5 STUDENT LABORATORY Plant Respiration and Photosynthesis Grade (Out of 20): Lab Credits: Full Name: Lab Section: Lab Instructor: Lab Date: Credit: 1 lab period Objectives: To explore the cycle of carbon dioxide gas as a plant undergoes cellular respiration in darkness and cellular respiration and photosynthesis in bright light. LABORATORY EXERCISE *Note This lab is due at the end of the lab period or as directed by your instructor. Your instructor may modify the lab based on time. Photosynthesis and Respiration in Plants: Pre-lab: ( 5 pts.) 1. Fill in the blanks. Terms (right) may be used once, more than once, or not at all. (2pts) During photosynthesis, plants harness energy and convert it to energy in the form of. This occurs in the. Photosynthesis utilizes the inorganic substance (gas), and converts it into energy-rich compounds and (gas). The reaction is summarized as: Photosynthesis: 6 CO H 2 O + sunlight ---> C 6 H 12 O O 2 ATP Carbon dioxide Chemical Chemical bonds Chloroplast Glucose Inorganic Mitochondria Organic Oxygen Solar Cellular respiration is a process by which energy stored in the of organic molecules is converted to, an energy form usable by the cell. Cellular respiration occurs in the. During respiration, organisms take in (gas) and release (gas). The reaction is summarized as: Cellular Respiration: 6O 2 + C 6 H 12 O > energy + 6CO 2 + 6H 2 O Cellular respiration occurs 24 hours a day in plants. However, photosynthesis only occurs when the plant is in sunlight. Plants perform photosynthesis at a much higher rate than respiration, thus taking in (gas) and releasing (gas) into the atmosphere during the day. At night, when no light is present, photosynthesis cannot occur, but the plant continues to perform cellular respiration, thus taking in (gas) and releasing (gas). 2. The picture below displays a flower in the sunlight, while the flower on the right is in the dark. For EACH plant, draw and label arrows indicating what goes into and out of each plant. Use the above reading as a resource. (2pts)

2 Pasco Plant Respiration and Photosynthesis Page 2 of 5 3. In this lab, you will measure the amount of carbon dioxide produced from plants. Write a hypothesis about carbon dioxide production will change when the plants are exposed to darkness then light. (1pt) Materials and Equipment: Data collection system, CO 2 sensor, sampling bottle, aluminum foil, lamp, spinach Procedure: (6 pts.) Getting started with the Spark unit: A procedure followed by a " " indicates a Tech Tip that may be referenced in the Pasco Tech Tip Guide. Your teacher has a guide on the front desk if you need clarification for a procedure. After you complete a step, place a checkmark in the box. (1pt for the procedure) You may find it easier to use the eraser end of a pencil than your finger to select items on the touch screen. *Note: Avoid bumping the equipment, because jarring or bumping the CO 2 gas sensor may cause it to record erratically. 1. Turn your spark unit on by pressing the power button on the bottom for 2 seconds and wait for the screen to load. This may take 30 seconds or more. 2. Plug the large end of the sensor extension cable into a 9-pin port on the Spark unit. Connect the other end of the cable to the CO 2 sensor. (2.1) 3. On your Spark unit, start a new experiment by selecting the Build button on the lower right corner of the data collection system home screen. 4. Under Carbon Dioxide Gas Sensor choose the CO 2 Concentration to display in parts per million (ppm). Note: the frame will turn orange when properly selected. Now select time on the Experimental Clock to display in seconds (s). (7.1.1) 5. Press the line graph icon in the upper left of the measurement palette grid and press OK. (7.1.1) (3.1) Your screen should now display a graph with CO2 Concentration on the Y axis, and Time (s) on the X axis.

3 Pasco Plant Respiration and Photosynthesis Page 3 of 5 6. Get 2-3 large or 3-4 smaller spinach leaves from your teacher. Use paper toweling and gently pat the leaves to remove any water from the surface. Place the sampling bottle on its side as shown in the figure below. 7. Add the leaves to the sampling bottle arranging them with the dark side facing up so their surface area is maximized (use the eraser end of a pencil to help with the placement). 8. Calibrate the CO 2 sensor buy pressing and holding the green (CAL) button for three seconds. The LED will stay on to indicate that calibration is in progress. Wait about a minute. When the LED starts to flash again, calibration is completed. 9. Place the CO 2 gas sensor into the sampling bottle so that the rubber stopper firmly plugs the end of the bottle. 10. Now you are ready to collect data (7.1.1) (3.1) Collect Data Part 1 In darkness 11. Keep the bottle placed on its side. Carefully cover the sampling bottle with aluminum foil to block out any ambient light. Position the lamp about 10 away from the sampling bottle with the light aimed toward it. Turn on the lamp. 12. Press the green play button on the bottom left of your screen to start data recording. Adjust the scale of Result: SPARKvue creates a new data run and starts recording data points into it. the graph to show all data. (7.1.2) The scale of the graph can be adjusted by pressing the blue graph icon 2. To stop above recording the play data, button select and the selecting Stop button. scale-to-fit icon erroneous data).. (*Note: Do not bump the sensor or it may record 13. Recall from the pre-lab that plants contain both chloroplast and mitochondria and are therefore able to carry out both photosynthesis and cellular respiration. What do you think will happen to the CO 2 level in the bottle while the plant is in the dark? Explain your answer (*Hint: plants only do photosynthesis when light is present). (2pts) 14. Record data for 5 minutes (300 seconds). At the end of 5 minutes, press the orange play button to stop Part 2 In light data collection (6.2) 15. Remove the aluminum foil from around the sampling bottle. Be careful not to remove the sensor from the bottle. 16. Place the bottle onto a small (approx. 5 x8 ) sheet of aluminum foil. Arrange the lamp in the same position it was in during the dark run. (*Note: Make sure that the tops of the leaves are pointing toward the light source). 17. Turn on the lamp.

4 Pasco Plant Respiration and Photosynthesis Page 4 of After the light is turned on, wait 3 minutes and then start data recording. (6.2) A second data set and graph line will automatically be generated in a different color. Adjust the scale of the graph to show all data. (7.1.2) 19. What is the purpose of the aluminum foil? (1pt) 20. What do you think will happen to the CO 2 level in the bottle while the plant is exposed to bright light? Explain your answer in terms of photosynthesis and respiration. (2pts) 21. Record data for 5 minutes, then stop data recording. (6.2) 22. Draw your trend line in the Data Analysis section below. Then clean up the equipment and work area (leaves go in the garbage, save the aluminum foil. Pack the probe and cord in the plastic bag along with the probe instructions. Turn the spark unit off). Data Analysis (9 pts.) 1. Graph a trend line below for CO 2 Concentration versus Time. Create a scale for the y-axis and label the data for dark and light conditions. (3pts) (Create a title above)

5 Pasco Plant Respiration and Photosynthesis Page 5 of 5 2. What is the relationship between CO2 production and light exposure? Explain your answer in terms of respiration and photosynthesis. (2pts) 3. (2pts) Answer Choice: Explanation 4. (2pts) Answer Choice: Explanation *Note Hand this lab in at the end of the lab period or as directed by your lab instructor.

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