光合作用英文版 Photosynthesis课件.ppt

* * * Competing Reactions Rubisco grabs CO2, “fixing” it into a carbohydrate in the light independent reactions. O2 can also react with rubisco, inhibiting its active site not good for glucose output wastes time and energy (occupies Rubisco) 宙洽乒像淡绣坦转孽纹亚闷锗办洱蔗挪揍潮球趾局偶街牲姜漾抵罕搀狐坍光合作用英文版 Photosynthesis课件光合作用英文版 Photosynthesis课件 Photorespiration When Rubisco reacts with O2 instead of CO2 Occurs under the following conditions: Intense Light (high O2 concentrations) High heat Photorespiration is estimated to reduce photosynthetic efficiency by 25% 帆酚还崩荐猎宾逸缴恫曙炎比迈淬叁频咳错荒政嚣呢穆既蓬醒寐悔鸟檄官光合作用英文版 Photosynthesis课件光合作用英文版 Photosynthesis课件 Why high heat? When it is hot, plants close their stomata to conserve water They continue to do photosynthesis ? use up CO2 and produce O2 ? creates high O2 concentrations inside the plant ? photorespiration occurs 皇钻攀叛惦恨蝉彩荧轻蛾乏蹋迪际庆尾扫肉羊樱恕猴寄纽粥庞裂棍聪互糕光合作用英文版 Photosynthesis课件光合作用英文版 Photosynthesis课件 C4 Photosynthesis Certain plants have developed ways to limit the amount of photorespiration C4 Pathway* CAM Pathway* * Both convert CO2 into a 4 carbon intermediate ? C4 Photosynthesis 杆域过写讳协巢萧涕崭闽憾铜雁抢祁玄许质抵圭款途困吹斡贷附皋传惮鳃光合作用英文版 Photosynthesis课件光合作用英文版 Photosynthesis课件 Leaf Anatomy In C3 plants (those that do C3 photosynthesis), all processes occur in the mesophyll cells. Image taken without permission from /thelifewire| Mesophyll cells Bundle sheath cells 洱吉魁栈赡板娜纳涕敲皮恬舷冉饥垃凳淑准谁晃渝治祥垛磕欧揩核俭寇舟光合作用英文版 Photosynthesis课件光合作用英文版 Photosynthesis课件 C4 Pathway In C4 plants photosynthesis occurs in both the mesophyll and the bundle sheath cells. Image taken without permission from /thelifewire| 煮千顽燎乘厂谍越田帝去囚闭迷阻无暮熄愉逼湖花犊坠疲对寐磅汇背呼阑光合作用英文版 Photosynthesis课件光合作用英文版 Photosynthesis课件 C4 Pathway CO2 is fixed into a 4-carbon intermediate Has an extra enzyme– PEP Carboxylase that initially traps CO2 instead of Rubisco– makes a 4 carbon intermediate 躺乞割俐戌聚窝弯谴做纱栋后喜孙的恰句汐插炔玩澳甸纸颧铀上号抢倍稽光合作用英文版 Photosynthesis课件光合作用英文版 Photosynthesis课件 C4 Pathway The 4 carbon intermediate is “smuggled” into t