Photosynthesis Lab Report PDF

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Photosynthesis Lab report...

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Photosynthesis & Respiration Lab

Jessica Borel Biol 1031 14 November 2019 Professor Ellis

BACKGROUND Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct. Through the process of photosynthesis, plants transform energy of sunlight into chemical energy stored in the bonds of sugar. Cells use cellular respiration to convert chemical energy stored in the bonds of sugar into energy in the form of ATP. ATP is a molecule that provides an immediate source of energy.

MATERIALS  Plant leaves  Computer  Vernier computer interface  Logger pro  Vernier CO2 gas sensor  250mL respiration chamber  Large beaker  Lamp  Aluminum foil  Forceps

OBSERVATIONS Photosynthesis’ equation is water + carbon dioxide + light energy yields glucose + oxygen; essentially sunlight yields to glucose. Photosynthesis occurs in the

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chloroplast and CO2 is consumed. Cellular respiration’s equations is glucose + oxygen yields water + carbon dioxide + energy; essentially glucose yields to ATP. Cellular respiration occurs in the mitochondria and CO2 is produced. We know that the spinach leaves are green meaning they are composed of chlorophyll, and this green pigment is involved in photosynthesis.

HYPOTHESIS The concentration of CO2 surrounding spinach leaves and the outside plant leaves in the dark increases, CO2 is produced. The concentration of CO2 surrounding spinach leaves and the outside plant leaves in the light decreases, CO2 is consumed. Control: Spinach leaves and outside plant leaves Dependent variable: CO2 concentration Independent variable: Spinach leaves exposure to light and darkness

PROCEDURES (TESTING HYPOTHESIS) Prepare the CO2 Gas Sensor for usage; turn it on and make sure it is inserted into Channel 1 of the Vernier computer interface. Collect 3-4 spinach leaves and insert them into respiration chamber carefully with the forceps after blotting the leaves dry. Wrap chamber in aluminum foil to ensure that no light will reach the leaves. Place the shaft of the CO2 Gas Sensor into the opening of the chamber. Wait 5 minutes so the leaves can acclimate. After the 5 minutes is up, begin measuring the CO2 concentration for 10 minutes by clicking collect. When data collection has finished, determine the rate of respiration highlighting the entire line and clicking the Linear Fit button. That will give you the slope of the line, m. as the rate of respiration. Store run by selecting “Store Latest Run” from the Experiment menu. Remove foil from chamber and fill the large beaker with 400 ml of water. Place beaker arm length away from the light source. Turn the light source on. The lamp should be on for 5 minutes prior to beginning data collection. After 5-minute time period is up click collect to begin data collection (10 minutes). After data collection is finished, determine the rate of photosynthesis by highlighting all the collected data and clicking on the Linear Fit button, choose “Latest CO2” and record the slope of the line, m, as the rate. Lastly remove spinach leaves from chamber using the forceps. Repeat all these steps for experiment two with the outside plant leaves.

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DATA/ CALCULATIONS Treatment Was CO2 consumed (-) or produced (+) in the chamber?

Spinach Leaves in the dark Spinach Leaves in the light Outside Plant Leaves Dark Light

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Produce (+) Consume d (-) Group 1 red/ yellow flower 0.678 -0.0212

Rate of change of CO2 (ppm/min ) in the chamber for your group 7.110

--49.152

R

Rate of change of CO2 (ppm/ min) in the chamber for other groups 0.59 4 2.35 3

Group 2 yellow flower

Group 3 witches brew

-0.04 -0.11

0.806 0.678

0.001 4 0.000 5 Group 4 purple berries & leaves 0.4323 -0.6388

0.72 1

0.106

0.19 1

0.55 1

0.614 3

1.10 2

Group 5 orange tree 61.680 -111.804

Group 6 leaf: flower 4:1 2.035 -2.111

GRAPH

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ANALYSIS OF DATA My groups data was an outlier due to a defect in the computer system. Instead of the data collection period being 10 minutes like every other groups, our group’s collection period was only 5 minutes. Despite the technical issue, our data still reflected CO2 being produced in the dark and consumed in the light. Group 2’s data was another outlier but only in the experiment using spinach leaves. The chamber tubes may have been defected. In experiment one with the spinach leaves, CO2 was produced in the dark for every group except group two and CO2 was consumed in the light for every group. In experiment two with the outside plant leaves, CO2 was consumed in the light for every group except group 3 (witches brew). CO2 was produced in the dark for every group except group 2 (yellow flower). CONCLUSION/ DISCUSSION Using prior knowledge that CO2 is consumed in light, and produced in the dark, we were able to formulate our hypothesis. We hypothesized that the spinach leaves that were placed in the dark would produce CO2 and the spinach leaves placed in the light CO2 would be consumed. Our hypothesis was accepted. Despite my group experiencing technical difficulties and only being able to carry out each experiment for 5 minutes opposed to 10 like all other groups, our data still reflected CO2 being consumed in light and produced in dark. Because of the technical difficulties, our groups data was an outlier for both the spinach leaf experiment and the outside plant experiment. There is always room for error in any experiment conducted. In this particular experiment, there was several chances error could occur. If the CO2 gas sensor wasn’t calibrated properly, if you didn’t allow 5 minutes for the leaves to acclimate, or if you didn’t put the beaker of water in between the chamber and the light source are a few examples of how error could occur. We were unable to determine whether it was an issue with the computer system or with the CO2 gas sensor that caused our data recordings to be stopped at 5 minutes each time.

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