Cellular Respiration Part III Krebs Cycle Figure 9

Cellular Respiration Part III: Krebs Cycle

Figure 9. 6 -3 Electrons carried via NADH Glycolysis Glucose Pyruvate Electrons carried via NADH and FADH 2 Citric acid cycle Pyruvate oxidation Acetyl Co. A CYTOSOL ATP Substrate-level phosphorylation Oxidative phosphorylation: electron transport and chemiosmosis MITOCHONDRION ATP Substrate-level phosphorylation ATP Oxidative phosphorylation

Citric Acid Cycle Krebs Cycle (Krebs Cycle)

Curriculum Framework 3. In the Krebs cycle, carbon dioxide is released from organic intermediates, ATP is synthesized from ADP and inorganic phosphate via substrate level phosphorylation, and electrons are captured by coenzymes. 4. Electrons that are extracted in the series of Krebs cycle reactions are carried by NADH and FADH 2 to the electron transport chain. 4

Figure 9. 11 Pyruvate CO 2 NAD Co. A NADH + H Acetyl Co. A Citric acid cycle 2 CO 2 3 NAD FADH 2 3 NADH FAD + 3 H ADP + P i ATP

Krebs Cycle • Occurs in the mitochondrial matrix • Releases the remaining carbons from the remnant glucose • Transfers the energy to NAD, FAD, and ADP 6

Figure 9. 12 -8 Acetyl Co. A-SH NADH H 2 O 1 + H NAD 8 Oxaloacetate 2 Malate Citrate Isocitrate NAD H 2 O Citric acid cycle 7 Fumarate NADH 3 + H CO 2 Co. A-SH -Ketoglutarate 6 4 Co. A-SH 5 FADH 2 NAD FAD Succinate GTP GDP ATP Pi Succinyl Co. A NADH + H CO 2

Figure 9. 12 a Acetyl Co. A-SH H 2 O 1 Oxaloacetate 2 Citrate Isocitrate

Figure 9. 12 b Isocitrate NADH 3 + H CO 2 Co. A-SH -Ketoglutarate 4 NADH Succinyl Co. A + H CO 2

Figure 9. 12 c Fumarate 6 Co. A-SH 5 FADH 2 FAD Succinate GTP GDP ATP Pi Succinyl Co. A

Figure 9. 12 d NADH + H NAD 8 Oxaloacetate Malate H 2 O 7 Fumarate

Where does each atom end up? C 6 H 12 O 6 12

So what did we get from Krebs? • Name the energy related end products of Krebs. • By what process is ATP formed? • Name the waste products. • Where do the events of Krebs occur? • Do cells in all kingdoms go through the Krebs cycle? • Where are the electrons headed? 13

So, What Did We Get From Krebs? 14

Figure 9. 6 -3 Electrons carried via NADH Glycolysis Glucose Pyruvate Electrons carried via NADH and FADH 2 Citric acid cycle Pyruvate oxidation Acetyl Co. A CYTOSOL ATP Substrate-level phosphorylation Oxidative phosphorylation: electron transport and chemiosmosis MITOCHONDRION ATP Substrate-level phosphorylation ATP Oxidative phosphorylation

Curriculum Framework • f. Cellular respiration in eukaryotes involves a series of coordinated enzymecatalyzed reactions that harvest free energy from simple carbohydrates. 16