Photosynthesis Lab Report

1392 WordsOct 29, 20136 Pages
Introduction Plants use a process called photosynthesis to covert energy from the sun into energy they can use for their activities. The plant’s chloroplasts, along with water, carbon dioxide, and light are the essential elements required for photosynthesis to take place. The “photo” part of photosynthesis is in reference to the fact that the process requires light. The simplest form of the photosynthesis equation is: H2O + CO2 ----light----> (CH2O)N + O2 As shown in the equation, photosynthesis produces carbohydrates, but more importantly, it produces oxygen. In 1937, Robert Hill discovered that chloroplasts in water could release oxygen if light and an electron acceptor are available. In his experiment, oxygen was still being…show more content…
This time length was chosen because longer blending periods might cause the chloroplasts to lose their functionality. While simultaneously avoiding CO2 that would cause the photosynthesis reaction to begin, four-layer cheesecloth filtered the solution so it only contained chloroplasts and not cell wall or any other organelles. Five test tubes were needed in our experiment: Tube 1, used for calibrating the spectrophotometer, contained 1 mL of buffer to neutralize the pH of the solution, 4 mL of water, and 3 mL of chloroplasts; Tube 2, the control tube, was only exposed to the fluorescent lights in the room; and three tubes that were used for the actual experiment, Tubes 3, 4, and 5, were assigned separately to each wattage variation. Tubes 2-5 were filled 1 mL of buffer, 3 mL of water, and 3 mL of chloroplasts. The calibration tube was used to set the spectrophotometer’s transmittance to a “base” or “zero” reading, making each experimental tube’s reading more accurate. The control tube held the same contents as the three experimental tubes, but it was not placed under a lamp. Instead, this tube was left alone in the fluorescent lights of the room to observe the chloroplasts’ photosynthetic behavior by themselves, without the aid of light bulbs shining on them that may increase their photosynthesis rates. Test tube racks were used to hold the tubes up in front of their designated lamps. A large Erlenmeyer flask filled

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