Energy Flow and Matter Cycling (Carbon) Sunlight energy Energy Flow and Matter Cycling (Carbon) ECOSYSTEM Photosynthesis in chloroplasts CO2 Glucose + + H2O O2 Cellular respiration in mitochondria ATP (for cellular work) Heat energy

Cellular Respiration The process by which an organism can extract energy from organic molecules (ex: glucose) and use that energy to make ATP

Cellular Respiration has 3 parts Glycolysis Krebs cycle Oxidative phosphorylation (AKA the electric transport chain)

Quick overview of the Cell

More detail of a plant cell

Structure of the Mitochondria

Glycolysis Occurs in the cytoplasm of the cell ATP is required to start the process Starts with glucose (6 carbons) produces 2 pyruvate, AKA pyruvic acid(3 carbons each) What do you gain (energy) at the end? ATP (2) NADH This is an electron carrier that will be used later

Glucose NAD+ + + 2 Pyruvate Fig. 6-7a Glucose 2 ADP 2 NAD+ + 2 P 2 NADH 2 ATP + 2 H+ 2 Pyruvate

Fig. 6-7c ENERGY INVESTMENT PHASE ATP Glucose ATP Steps – A fuel molecule is energized, using ATP. 1 3 Step 1 ADP P Glucose-6-phosphate 2 P Fructose-6-phosphate ATP 3 ADP P P Step A six-carbon intermediate splits Into two three-carbon intermediates. Fructose-1,6-bisphosphate 4 4 P P Glyceraldehyde-3-phosphate (G3P) Step A redox reaction generates NADH. 5 NAD+ 5 NAD+ 5 ENERGY PAYOFF PHASE NADH P NADH P + H+ + H+ P P P P 1,3-Bisphosphoglycerate ADP ADP 6 6 ATP ATP P P 3-Phosphoglycerate 7 7 Steps – ATP and pyruvate are produced. 6 9 P P 2-Phosphoglycerate 8 8 H2O H2O P P Phosphoenolpyruvate (PEP) ADP ADP 9 9 ATP ATP Pyruvate

Modeling Glycolysis Beans = electrons Blue balls = carbon atoms Yellow balls = phosphate Red ovals = ADP Green rectangles = NAD+

Fig. 6-7b ATP made in Glycolysis is by the process of substrate level phosphorylation Enzyme Enzyme P ADP + ATP P P Substrate Product

What’s next? Pyruvate (pyruvic acid) goes into the mitochondrial matrix Here it gets converted into acetyl-CoA This will enter the Krebs (citric acid) cycle Krebs cycle Our sugar continues to be broken down releasing Carbon dioxide ATP (1 per pyruvate) is made NADH and FADH2 are made These carry electrons to the electron transport chain

Modeling the Krebs cycle Beans = electrons Blue balls = carbon atoms 7 Yellow balls = phosphate 1 Red ovals = ADP 1 Green rectangles = NAD+ 4 Green hearts = FAD 1 Red square = Coenzyme A (CoA) 1

Oxidative phosphorylation electron transport chain The electron carriers (NADH and FADH2) take the electrons to the electron transport chain located on the inner membrane Energy from the electrons moving through the chain provide the power to make ATP About 34 ATP are made

NADH and FADH2 give electrons at the beginning of the chain Oxygen takes electrons away at the end Forming water

Modeling oxidative phosphorylation (the electron transport chain) H+ = small green balls Oxygen = medium blue balls Electrons = beans proteins of the electron transport chain = large red ATP synthase = Large blue ADP = red oval Phosphate = yellow ball NADH = green rectangle with electrons FADH 2 = green heart with electrons

Aerobic Respiration This process occurs in the mitochondria