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Effects of Smog on Photosynthesis

Effects of Smog on Photosynthesis. Photosynthesis Plants convert carbon dioxide and water into carbohydrates using the energy of light, and release oxygen. 6CO 2 +6H 2 O+light/chlorophyll = C 6 H 12 O 6 +6O 2. Smog

myles-barrett
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Effects of Smog on Photosynthesis

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  1. Effects of Smog on Photosynthesis

  2. Photosynthesis Plants convert carbon dioxide and water into carbohydrates using the energy of light, and release oxygen. • 6CO2+6H2O+light/chlorophyll = C6H12O6+6O2

  3. Smog A smoky fog emitted by various industries, and released into the surrounding environment. Two types of smog: 1) Industrial and 2) Photochemical

  4. Industrial smog Produced by burning of carbon compounds or coal Made of sulfur oxides and particulate matter

  5. Photochemical smog Produced by auto emissions: Nitric oxide (NO), carbon dioxide (CO2), and hydrocarbons (HC) Reactions of these chemicals in the atmosphere produce: Nitric acid or acid rain (HNO3), formaldehyde, and ozone (O3) Ozone reacts with other pollutants to form secondary pollutants,such as peroxyacyl nitrates (i.e. PANs) • This type of smog behaves like a filter for sunlight!!

  6. The Problem with SMOG Not limited to large cities Smog travels halfway around the globe! Did you know? Smog alert for Statesboro (1999).

  7. Photochemical Smog and Photosynthesis Causes two main problems for plants: 1) Ozone destroys the leaves of plants because it acts as an oxidizing agent 2) Filtered sunlight limits amount of photosynthesis, which is crucial for plants

  8. Photosynthesis in chloroplasts • Photosynthesis has 2 parts: • Light reactions: produce ATP and NADPH (high energy molecules that store energized electrons) • 2) Calvin cycle: synthesis takes place. CO2 is converted to carbohydrates (mass of the plant) using ATP and NADPH as power houses

  9. Our Goals • To replicate the effects of smog on photosynthetic activity • To test the relationship between different levels of light intensity, and the rate of photosynthetic activity.

  10. Methods • Plants (in the form of chlorophyll) • Light source • Filters (to simulate smog) • How do we measure photosynthetic rate? • Dichlorophenol-indophenol (DCPIP) • DCPIP reduced (electrons) = colorless = NADPH • DCPIP oxidized (no electrons) = blue = NADP

  11. Procedure • To measure the change in concentration of the blue dye using a spectrophotometer • This change in color will allow us to quantify the amount of photosynthesis taking place. • See procedure in lab manual

  12. Continued • Each lab bench will have progressively highly filtered light sources (to simulate higher rates of smog). • Light intensity is already defined for each bench.

  13. The Spectrophotometer • Measures the absorbance (a) of light by a solution at a given wavelength. • An internal light shines a beam of light thru an opening; hits an objective lens, and gets separated into wavelengths • These wavelengths pass thru the sample, and the light that is not absorbed is transmitted trough and detected by a specialized phototube.

  14. A spectrophotometer measures the absorbance of light by a colored solution at a given wavelength. • Since DCPIP acts just like NADP • What should the reading be for a filtered light source? • What about a non-filtered light source?

  15. Expected Results • Unfiltered light • Photosynthesis increases • DCPIP re increases • Light passing through sample increases • Absorbance reading is lower • Filtered light • All of the opposite

  16. Next Lab • Global Climate Change • Bring calculator • Smog worksheet + graph • Eutrophication hypothesis • Scientific article # 3 • Start summarizing articles

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