Electron Carriers Electron carriers are molecules that will

Electron Carriers Electron carriers are molecules that will “pick up” one or two hydrogen ions and electrons and carry them to another location. Examples: Photosynthesis = NADP + Cellular Respiration = NAD + & FAD+ copyright cmassengale 1

The Photosynthesis Equation copyright cmassengale 2

Photosynthesis Overview copyright cmassengale 3

1 st Step of Photosynthesis • Light-Dependent Reactions – Requires light (Energy Source) – Occurs in the Thylakoids • In the Chlorophyll (inside the Thylakoids) • Across the Membrane of the Thylakoids

Light-Dependent Reactions • These reactions use water molecules to produce oxygen gas. • They use energy from light to produce ATP and NADPH (an electron carrier). • They convert – ADP into ATP – NADP+ into NADPH

Light-Dependent Big Idea Light is absorbed by chlorophyll to split water molecules and give off oxygen. This “charges up” the energy molecules ATP and NADPH.

Light Absorption & Chemiosmosis Light is absorbed by Chlorophyll TWICE during the Light Dependent Reaction. 1. Photosystem 2 splits H 2 O & gives off Oxygen gas 2. Electrons are excited and are carried to Photosystem 1 3. Photosystem 1 pumps H+ ions into the Thylakoid (AGAINST the gradient) and stores energy in NADPH 4. Chemiosmosis occurs to produce ATP. copyright cmassengale 7

Chemiosmosis SUN H+ H + Thylakoid E PS II (Proton Pumping) T PS I C H+ H+ H + H+ ADP + P H+ H+ high H+ concentration ATP Synthase ATP Thylakoid Space low H+ concentration 8

Light Reaction Summary Reactant: H 2 O Also Needed: Light Energy, Chlorophyll, ADP & NADP Products: • O 2 (PS II; released into atmosphere) • ATP (chemiosmosis) • NADPH (PS I; used in the Calvin Cycle) copyright cmassengale 9

2 nd Step of Photosynthesis • Calvin Cycle – a. k. a. Light-Independent Reactions or Carbon Fixation – Does NOT require light • Uses Energy Storage Molecules (ATP & NADPH) – Occurs in the Stroma copyright cmassengale 10

Calvin Cycle (Light-Independent Reactions) • Uses CO 2 and the “Left-over” Hydrogen from NADPH. • Produces Glucose (C 6 H 12 O 6). • These reactions use the ATP and NADPH produced in the lightdependent reactions to produce high-energy sugars.

nd 2 Step of Photosynthesis Calvin Cycle • aka Light Independent Reaction, Dark Reaction, Carbon Fixation or C 3 Fixation • Uses energy (ATP and NADPH) from light reaction to make sugar (glucose). • Occurs in the stroma • Uses 6 CO 2 12

REMEMBER • The following were produced during the Light-Dependent Reaction: – O 2 (released into the atmosphere) – NAPDH & ATP (used for ENERGY in the Calvin Cycle) copyright cmassengale 13

Calvin Cycle • Big Idea: 6 CO 2 molecules are “fixed” into Glucose (C 6 H 12 O 6) • ADP & NADP+ are reused in the next light-dependent reaction C 3 Remember: CO 2 = Calvin Cycle Glucose 14

Calvin Cycle Big Idea (Light -Independent) Energy is used from ATP and NADPH. The “left-over” hydrogens from the water are carried to the stroma by NADPH. They are combined with CO 2 to make glucose.

Light Dependent • Energy Source= Light • Occurs in the Thylakoids (Chlorophyll & membranes) • Changes ADP into ATP • Changes NADP into NADPH • Uses H 2 O • Produces Oxygen Gas Calvin Cycle • Energy Source = ATP and NADPH • Occurs in the Stroma • Changes ATP into ADP • Changes NADPH into NADP • Uses CO 2 & “left-over” H from NADPH • Produces Glucose

Photosynthesis Overview copyright cmassengale 17

Light Dependent Reaction Simulation • http: //www. youtube. com/watc h? v=RFl 25 v. SEla. E • Video http: //www. youtube. com/watch? v=v 590 JJV 96 lc • Rap http: //www. youtube. com/watch? v=p. E 82 qt. KSSH 4 • Light Dependent Claymation http: //www. youtube. com/watch? v=CLf 4 yu 8 Iwo 0 copyright cmassengale 18

More Videos • Calvin Cycle Claymation https: //www. youtube. com/watch? v=hhkp. Jw. SDx. QQ • Calvin Cycle Animation https: //www. youtube. com/watch? v=E_XQR 800 Ag. M • Crash Course Biology: Photosynthesis https: //www. youtube. com/watch? v=s. QK 3 Yr 4 Sc_k copyright cmassengale 19

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