Important La@n Roots Auto Self Throph Photo Feeding Hetero Other Photosynthesis: Organic Molecule (food) Production through Solar Power Sunlight energy enters ecosystem C 6 H 12 O 6 Glucose Oxygen Photosynthesis C Carbon dioxide H 2 O Water Cellular respira8on drives cellular work Heat energy exits ecosystem Figure 6.2 Zannie Dallara 1
energy 6 C 6 H 2 O C 6 H 12 O 6 Photo- Carbon dioxide Water synthesis Glucose 6 Oxygen gas Figure 7.UN1 Vein Inner Outer Granum Stroma Thylakoid C Stomata Leaf cross sec8on Interior cell LM TEM Zannie Dallara 2
AUTOTROPHS: Self Eaters Plants (mostly on land) Some Pro8sts (aqua8c) Forest plants Kelp, a large alga Some Bacteria (aqua8c) Cyanobacteria Fig 7.1 Vein Guard Cells - Protect against water loss C Stomata - Pore for gas exchange Leaf cross sec8on Figure 7.2a Photosynthesis occurs in two stages: 1. The Reac8ons convert solar energy to chemical energy 2. The Calvin cycle uses the products of the light reac@ons to make sugar from carbon dioxide A Photosynthesis Road Map Zannie Dallara 3
Gamma rays X- rays Increasing wavelength 10 5 nm 10 3 nm 1 nm 10 3 nm 10 6 nm 1 m 10 3 m UV Infrared Micro- waves Radio waves Visible light 380 400 500 600 700 750 Wavelength (nm) Wavelength = 580 nm Figure 7.4 Reflected light Absorbed light Transmi_ed light Figure 7.6 Lots of different Pigments are capable of photosynthesis Figure 7.7 Zannie Dallara 4
A photosystem is a group of chlorophyll and other molecules in the thylakoid that func@on as a light- gathering antenna. How s Harvest Energy behaves as discrete packets of energy. Chlorophyll molecules absorb photons. Electrons in the pigment gain energy. These electrons go down an ETC, releasing energy Pigment molecules Photon Electron transfer Primary electron acceptor Reac8on- center chlorophyll a Antenna pigment molecules Reac8on center Thylakoid Transfer of energy H 2 O C Stack of thylakoids reac8ons ADP P Calvin cycle Stroma Sugar (C 6 H 12 O 6 ) Figure 7.UN5 Zannie Dallara 5
How the Reac@ons Generate and Two types of photosystems cooperate in the light reac@ons: 1. The water- spli\ng photosystem Use sunlight to split water 2. The - producing photosystem The water- splicng photosystem Figure 7.11 How the thylakoid converts light energy to the chemical energy of and To Calvin cycle ADP + P Stroma Thylakoid Electron transport chain synthase Inside thylakoid H2O 1 2 Electron flow 1. The water- spli\ng photosystem e acceptor ADP 2. The - producing photosystem e acceptor Electron transport chain Photon Photon Chlorophyll H2O 2 1 + O2 2 Chlorophyll Water- splicng photosystem - producing photosystem Zannie Dallara 6
Bio 10 - Lecture 9: Photosynthesis ETC works like a Dam Inside Thylakoids Dam = Thylakoid Membrane e- Transport Chain P AT ase th syn Outside Thylakoids 1. - Dependent Reactions Gave Us: S8ll no CO2 used! THE CALVIN CYCLE: MAKING SUGAR FROM CARBON DIOXIDE The Calvin cycle: Func@ons like a sugar factory within the stroma of a chloroplast 2010 Pearson Education, Inc. Zannie Dallara 7
To Calvin cycle ADP + P Stroma Thylakoid Electron transport chain synthase Inside thylakoid H2O 1 2 Electron flow Figure 7. Summary: Calvin cycle CO2 Calvin cycle ADP P G3P P Glucose and other compounds Figure 7.UN7 2. -Independent Reactions: Calvin Cycle C 6 H 12 O 6 We can build a tree from this! Zannie Dallara 8
energy 6 C 6 H 2 O C 6 H 12 O 6 Photo- Carbon dioxide Water synthesis Glucose 6 Oxygen gas Figure 7.UN1 Evolu@on Connec@on: Solar- Driven Evolu@on 3 types of plants 1. C 3 plants: Use C directly from the air Are very common and widely distributed 2. C 4 plants: Close their stomata to save water during hot and dry weather Can s@ll carry out photosynthesis 3. CAM plants: Are adapted to very dry climates Open their stomata only at night to conserve water 2010 Pearson Education, Inc. Zannie Dallara 9