Catalyst  Could humans survive without plants? Why, if at all, are plants important?

Cell Parts: Chloroplast  Photosynthesis: occurs only in plants (not animals!)  6CO 2 + 6H 2 O + light  C 6 H 12 O 6 + 6O 2 (glucose sugar) (oxygen) (carbon dioxide)(water) (energy) stored in plant; for plant use or animal use with cellular respiration released from leaves absorb through leaves from roots from sun Image Source:

 Chloroplast: capture light energy; make food energy

Cell Parts: Chloroplast Image Source:  Thylakoid: flattened discs containing chlorophyll  Granum (pl. Grana): stack of thylakoids  Stroma: fluid inside chloroplast (similar to a cell’s cytoplasm)  Lamella: links thylakoids in grana together  Lumen: inside of the thylakoid

Cell Parts: Chloroplast  Chlorophyll: pigment in chloroplasts that absorbs light  Review: Visible Light Spectrum Violet IndigoBlueGreenOrangeRedYellow “VIB G YOR” (or “ROY G BIV”)

Cell Parts: Chloroplast  The color you see is the color that is reflected  Chlorophyll reflects green; absorbs ROYBIV! R O Y G B I V Reflects: Absorbs: We See: RED OTHER COLORS RED Light energy the plant uses!!!!

Cell Parts: Chloroplast  Phase I: Light-Dependent Reactions  Phase 2: Light-Independent Reactions / Calvin Cycle Image Source: bioweb.uwlax.edu

Cell Parts: Chloroplast  Phase 1: Light-Dependent Reactions  Occurs at thylakoid membrane (Lumen  Stroma)  Requires light (dependent)

Cell Parts: Chloroplast  Phase I: Light-Dependent Reactions

Cell Parts: Chloroplast  Phase 1: Light-Dependent Reactions  Mini-Steps: 1. Photosystem II absorbs light energy to spilt water into: oxygen, H + s in lumen, & activated e - that enters the ETC. 2. Electron Transport Chain – e - s move through membrane to pump H + s into lumen. 3. Photosystem I absorbs light energy and re- energizes e -, which moves to ferrodoxin (protein) to form NADPH. 4. H + s accumulate in lumen to create a gradient (high [H + ] in lumen, low [H + ] in stroma). 5. ATP Synthesis – As H + s move across thylakoid membrane through ATP Synthase, ADP is converted into ATP. Chemiosmosis

Cell Parts: Chloroplast  Phase 2: Calvin Cycle / Light-Independent Reactions  In stroma  Doesn’t directly require light energy (independent)  ATP & NADPH = energy, but not stable  converted to glucose sugar.

Cell Parts: Chloroplast  Phase 2: Calvin Cycle 12 3-PGA CCC 12 G3P CCC Rubisco CO 2 6 ribulose 5-phosphate CCCCC ribulose 1,5-bisphosphate6 CCCCC 2 G3P CCC Transported from chloroplast to make glucose, fructose, starch, etc. (carbohydrates / sugars) 12 ATP 12 ADP 12 NADPH 12 NADP + 6 ATP 6 6 ADP Calvin Cycle (3-phosphoglyceric acid) (glyceraldehyde 3-phosphate)

Cell Parts: Chloroplast  Phase 2: Calvin Cycle  Mini-Steps: 1. Carbon Fixation: Carbon dioxide joins a five-carbon molecule to make twice as many three-carbon molecules. 2. ATP & NADPH turn 3-PGA into G3P (a high energy molecule). ATP supplies phosphate groups; NADPH supplies H + s and e - s. 3. Two G3P molecules leave to make glucose & other carbohydrates. 4. Rubisco (enzyme/protein) converts remaining ten G3P molecules into five-carbon molecules to be used in carbon fixation PGA CCC 12 G3P CCC Rubisco CO 2 6 ribulose 5-phosphate CCCCC ribulose 1,5-bisphosphate6 CCCCC 2 G3P CCC 12 ATP 12 ADP 12 NADPH 12 NADP + 6 ATP 6 6 ADP Calvin Cycle (3-phosphoglyceric acid) (glyceraldehyde 3- phosphate)

Cell Parts: Chloroplast  Phase I: Light-Dependent Reactions  Photosystem II uses light to split water: H + s, oxygen, & e -.  ETC: e - pumps H + s into lumen.  Photosystem I re-energizes e- with light: forms NADPH.  H+s in lumen create a concentration gradient.  H+s move across thylakoid membrane through ATP Synthase: converts ADP into ATP  Phase 2: Light-Independent Reactions / Calvin Cycle  CO 2 molecules join with 5-carbon molecules to make 3-PGA molecules.  NADPH and ATP from Light-Dependent Reactions turn 3-PGA into G3P.  Two G3P molecules leave the Calvin Cycle to form glucose & other carbohydrates.  Remaining G3P molecules converted by Rubisco into 5-carbon molecules that restart the cycle. Image Source: bioweb.uwlax.edu