Presentation on theme: "Chapter 7 - Photosynthesis Almost all plants are photosynthetic autotrophs, as are some bacteria and protists –They generate their own organic matter through."— Presentation transcript:
Chapter 7 - Photosynthesis Almost all plants are photosynthetic autotrophs, as are some bacteria and protists –They generate their own organic matter through photosynthesis.. (a) Mosses, ferns, and flowering plants (b) Kelp (c) Euglena (d) Cyanobacteria
Meso- phyll Vein Stomata Leaf cross sectionMesophyll cell Chloroplast Inner membrane Outer membrane GranaStromaThylakoid space Photosynthesis occurs in the chloroplasts, which: –Are found in the cells of the mesophyll –Contain stroma, a thick fluid –Contain thylakoids, membranous sacs in stacks called grana..
The reactants and products of the reaction.. The Overall Equation for Photosynthesis Light energy Carbon dioxide Water Photo- synthesis Glucose Oxygen gas
Photosynthesis is a two-step process: –Light reactions – require sunlight energy to split water molecules into 2H and O 2 –Calvin Cycle (dark reactions) – hydrogen generated from the light reactions is used to reduce CO 2 to generate sugar – does not require sunlight Leaves absorb CO 2 through stomata..
Chlorophyll molecules absorb photons –Electrons in the pigment gain energy –The energy is released and used.. Excited state ee Heat Light Photon Light (fluorescence) Chlorophyll molecule Ground state 12 (a) Absorption of a photon (b) fluorescence of isolated chlorophyll in solution (c) Fluorescence of a glow stick
The light reactions in the thylakoid membrane 2NADP+ 2NADPH 2 – 2H 2 O O 2..
Light To Calvin Cycle Stroma Thylakoid membrane Electron transport chain ATP synthase Inside thylakoid 1/21/2 NADP ADP + P Light Reactions
The Calvin cycle –Functions like a sugar factory within a chloroplast –Regenerates the starting material with each turn 6NADPH 2 6NADP + 12H 6CO 2 C 6 H 12 O 6 The Calvin Cycle: Making Sugar From Carbon Dioxide
Input 3 CO PGA 6 6 ADP NADP 6 G3P Glucose and other compounds Output 5 G3P 3 3 ADP 3 RuBP Calvin cycle 1 G3P
Photosynthesis has an enormous impact on the atmosphere –It swaps CO 2 in the atmosphere for O 2 Why do we need the O 2 ?..