1 / 13

Factors Affecting Photosynthesis & Photosynthesis Vs. Cellular Respiration

Factors Affecting Photosynthesis & Photosynthesis Vs. Cellular Respiration. Section 3.5 & 3.6. Factors affecting Photosynthesis. The rate of photosynthesis can be determined by measuring either: CO 2 uptake O 2 production. Factors affecting Photosynthesis.

magnar
Download Presentation

Factors Affecting Photosynthesis & Photosynthesis Vs. Cellular Respiration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Factors Affecting Photosynthesis &Photosynthesis Vs. Cellular Respiration Section 3.5 & 3.6

  2. Factors affecting Photosynthesis • The rate of photosynthesis can be determined by measuring either: • CO2 uptake • O2 production

  3. Factors affecting Photosynthesis • HOWEVER, CO2 and O2 participate in 2 other metabolic processes within plant cells • Cellular respiration (happens in all plant cells) • Photorespiration (happens primarily in C3 plants) • Both of these pathways consume O2 and release CO2

  4. Factors affecting Photosynthesis • Therefore it is necessary to measure net gas exchange between a plant and its environment, using the following equation: Net CO2 uptake = CO2 uptake – CO2 prod’n – CO2 prod’n (rate of (Photosyn’s) (Cell. Respn) (Photorespn) photosynthesis)

  5. Light Intensity • Light – saturation point • Rubisco enzymes are saturated  photosynthesis cannot go any faster • Light compensation point • CO2 in = CO2 out • Net CO2 = ZERO! • Dark Respiration Rate: cellular respiration produces CO2, thus net CO2 uptake is negative.

  6. Carbon Dioxide Availability • High CO2 concentration: • Increased photosynthesis, because higher CO2 levels allow Rubisco enzymes to “take on” more CO2, even if O2 is present • Plateau still reached when Rubisco enzymes are saturated

  7. Temperature • From 10 – 30 ˚C, photosynthesis is directly proportional to temperature • ↑ temp causes ↑collisions /molecular activity) • Above 30 ˚C, photosyn’s rate ↓ • Temp ↑ causes denaturation • Max rates between 20-30 ˚C • Remember: all enzymes have diff optimal temp for max activity / productivity

  8. Oxygen Concentration • High levels of O2 have an inhibitory effect on photosynthesis, because of competition between O2 and CO2 active sites on Rubisco enzymes Rubisco + CO2 carbon fixation via photosynthesis Rubisco + O2  photorespiration

  9. Photosynthetic efficiency • Equals the net amount of CO2 uptake per unit of light energy absorbed • Also called the quantum yield • Is determined by calculating the slope of the light-response curve

  10. Photosynthetic efficiency • Note that initial slope of the curve is greater at the lower temperature • For most C3 plants, as temp increases, the rate of photorespiration increases more rapidly than the rate of photosynthesis

  11. Photosynthetic efficiency • Therefore, in most C3 plants, the net CO2 uptake per unit of light absorbed (i.e. Photosynthetic efficiency) decreases as the temp. Increases • (line A on the graph)

  12. Photosynthesis VersusCellular Respiration Section 3.6  Last one!!!!!!1!11!1!

  13. “Worksheet Time!” Says Happy Dragon!

More Related