Photosynthesis [8.2] Cell Respiration [8.3] Fermentation [8.3] Metabolism Photosynthesis [8.2] Cell Respiration [8.3] Fermentation [8.3]

Photosynthesis Most autotrophs create energy from the sun using photosynthesis The overall equation is: 6CO2 + 6H2O C6H12O6 + 6O2 This occurs in Two Phases: Light Reaction The Calvin Cycle SUNLIGHT

6CO2 + 6H2O C6H12O6 + 6O2 Light-Reaction Phase: Photosystem II SUNLIGHT Light-Reaction Phase: Photosystem II Uses energy from light to break down H2O Releases O2 Photosystem I Harnesses electrons from broken H2O molecules to produces NADPH Chemiosmosis Uses H+ ions from broken H2O molecules to harvest the energy to turn ADP into ATP

6CO2 + 6H2O C6H12O6 + 6O2 Calvin Cycle: SUNLIGHT Calvin Cycle: Uses CO2 and the energy stored in NADPH and ATP to produce Glucose (C6H12O6)

Alternate Pathways The environment effects a plant’s ability to perform photosynthesis Two alternate pathways exist: C4 plants CAM plants

Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O + ATP Function: to harvest electrons from glucose to produce ATP Overall Equation: Three Stages: Glycolysis Citric Acid Cycle (CAC) [Kreb’s Cycle] Electron Transport Chain (ETC) C6H12O6 + 6O2 6CO2 + 6H2O + ATP

Transition to the Citric Acid Cycle Glycolysis C6H12O6 + 6O2 6CO2 + 6H2O + ATP Glycolysis is anaerobic, meaning that it does not require oxygen. Glucose is broken down yielding: Energy (ADP -> ATP) Electron carriers (NADH) Pyruvate Transition to the Citric Acid Cycle C6H12O6 + 6O2 6CO2 + 6H2O + ATP Requires oxygen (Aerobic) Pyruvate converted to Acetyl CoA

Citric Acid (Kreb’s) Cycle C6H12O6 + 6O2 6CO2 + 6H2O + ATP Step 1- Acetyl CoA Citric Acid Step 2- Citric Acid broken down: Energy (ADP -> ATP) Electron carriers: NADH & FADH2 Waste CO2 Step 3- Acetyl CoA and Citric Acid are regenerated to repeat the cycle.

Electron Transport Chain C6H12O6 + 6O2 6CO2 + 6H2O + ATP A flow of electrons from electron carriers NADH & FADH2 are used to harness energy ETC is Aerobic Final electron acceptor is Oxygen H+ + O2 = H2O Net 36 ATP in Eukaryotes, 38 ATP in Prokaryotes

Anaerobic Respiration What happens when there is NO oxygen? Glycolysis can still occur Kreb’s cycle and electron transport cannot Instead, pyruvate goes into the anaerobic process known as fermentation Occurs entirely in the cytoplasm and regenerates NAD+

Fermentation Two Types: Lactic Acid Fermentation- Pyruvate is converted into lactic acid In muscle cells, occurs when body cannot supply enough oxygen In microorganisms this occurs to make cheeses, yogurts, and sour cream.

Fermentation Two Types: Alcohol Fermentation Occurs in yeast and some bacteria Converts pyruvate into CO2 and ethanol NAD+ is regenerated