PHOTOSYNTHESIS. The reverse of cellular respiration It is already known that photosynthesis is the reverse reaction to cellular respiration

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PHOTOSYNTHESIS Slide 2 The reverse of cellular respiration It is already known that photosynthesis is the reverse reaction to cellular respiration Slide 3 More than you realise In fact, from a basic level of energy analysis, photosynthesis is, in every way, the opposite of cellular respiration Cellular respiration uses glucose to create chemical energy needed to produce ATP Whereas photosynthesis CREATES glucose How do you think the MECHANISM by which plants do this (photosynthesis) is going to look like when compared to cellular respiration? Slide 4 Plants eat too Before moving on, it is worth mentioning that plants also use energy Remember that plants, as living organisms, also undergo cellular respiration they need energy to grow, and to move (yes, some plants can do that) Some plants, however, produce much more energy than is needed and can store it for times when energy is scarce like winter (ie. Maple tree sap that we use to create maple syrup from) Slide 5 Autotrophs Plants, of course, are not the only organisms that are capable of photosynthesis Slide 6 Structure Slide 7 Slide 8 chloroplasts The most important organelle found in plant cells required for the process of photosynthesis is the chloroplast What is your first impression of the chloroplast when you take a look at its physical structure? Slide 9 Slide 10 Slide 11 Structure = function Slide 12 The question of electrons In cellular respiration, we relied upon the breakdown of glucose to free chemical energy that was stored in its bonds Slide 13 Jumping electrons The sun in photosynthetic reactions, therefore, is the energy that is being harnessed to produce energy Slide 14 What if this energy is captured? The concept then, for photosynthesis is simple: Slide 15 Plant pigments Ofcourse, though the overall concept is simple, the actual biochemistry behind it is complex (just like the flaming gummi bear to represent energy in glucose) Slide 16 CHLOROPHYLL The one unifying feature of many plants is the characteristic green colour that we associate plants and therefore, appropriately, life Slide 17 Why? A pigment, ultimately, is able to absorb specific wavelengths of light in the electromagnetic spectrum We see green because that range of wavelengths that is not absorbed rather it is transmitted or reflected lies within the wavelengths or frequencies of light that our brains interpret as being green Slide 18 Slide 19 overview Photosynthesis can be divided into two parts: Slide 20 Slide 21 Photosystems Is the fancy word for enyzmes similar to the ones found in the electron transport chain in the membrane of the thylakoids Slide 22 PHOTOSYSTEM ii Chlorophyll absorbs light energy and an electron is excited out of the chlorophyll Slide 23 Photosystem I Upon reaching photosystem I, more light is used to further excite the electron to a higher level of energy This electron is then passed on through the enzyme membrane and is picked up by NADP (which is the terminal electron acceptor) to produce NADPH Slide 24 http://highered.mcgraw- o13.swf::Photosynthetic%20Electron%20Transport%20and%20ATP%20Synthesis Slide 25 Dark reactions calvin cycle Glucose is produced in the dark reactions when the energy stored in the reduction of the ATP and the NADPH light reactions is used to power the chemical reactions needed to turn carbon dioxide into glucose Slide 26 http://highered.mcgraw- w0/chapter5/animation_quiz_1.html Slide 27 PROGRESSION OF INTERMEDIATES Recall that in glycolysis, G3P is produced first before 3PG In that sense, G3P is closer chemically to glucose in the chain of reactions Notice that in the Calvin cycle, the movement towards the formation of glucose requires the formation of 3PG BEFORE G3P