Cellular Respiration Fig. 9-1 Figure 9.1 How do these leaves power the work of life for the giant panda?

Are you the “slow-twitch” or “fast-twitch”? 2:15:25 London 2003

Florence Griffith Joyner 100M – 10.49s 1988

Berlin Marathon 2008

The Race

Diagrams from slides 11, 19 and 22 may be drawn on your note card to use during the quiz. You should have 2 copies of completed Diagram 22 in your notes (one created by you and one from me). Think about what happens in each of the processes as you again recreate them on the note card.

Fast twitch muscle slow twitch muscle

What makes these muscle fibers different? The process for making ATP varies Slow fibers do it aerobically (O2) Fast fibers w/o O2 (anaerobic) # of mitochondrion vary, amt. of myoglobin

Efficiency of Cellular Respiration 36-38 ATP per glucose molecule 40% of energy from glucose is harvested 60% heat 1 muscle cell spends/regenerates 10 million ATP/sec

Organic molecules Cellular respiration in mitochondria Fig. 9-2 Light energy ECOSYSTEM Photosynthesis in chloroplasts Organic molecules CO2 + H2O + O2 Cellular respiration in mitochondria Figure 9.2 Energy flow and chemical recycling in ecosystems ATP ATP powers most cellular work Heat energy

C6H12O6 + 6 O2  6 CO2 + 6 H2O + Energy Energy = (ATP + heat) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 9-UN3 becomes oxidized becomes reduced

The Stages of Cellular Respiration: A Preview Cellular respiration has three stages: Glycolysis (breaks down glucose into two molecules of pyruvate) The citric acid cycle (completes the breakdown of glucose) or Krebs Cycle Oxidative phosphorylation (accounts for most of the ATP synthesis) or ETC Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Aerobic Cellular Respiration Electron Transport Chain Carbon dioxide + water Glucose + oxygen Glycolysis Krebs Cycle

Electrons carried via NADH Electrons carried via NADH and FADH2 Fig. 9-6-2 Electrons carried via NADH Electrons carried via NADH and FADH2 Glycolysis Citric acid cycle Glucose Pyruvate Mitochondrion Cytosol Figure 9.6 An overview of cellular respiration ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation

Hans Krebs – Nobel Prize 1953 Citric acid cycle

Pyruvate CO2 NAD+ CoA NADH + H+ Acetyl CoA CoA CoA Citric acid cycle 2 Fig. 9-11 Pyruvate CO2 NAD+ CoA NADH + H+ Acetyl CoA CoA CoA Citric acid cycle 2 CO2 Figure 9.11 An overview of the citric acid cycle FADH2 3 NAD+ FAD 3 NADH + 3 H+ ADP + P i ATP

Electron transport chain 2 Chemiosmosis Fig. 9-16 H+ H+ H+ H+ Protein complex of electron carriers Cyt c V Q   ATP synthase  2 H+ + 1/2O2 H2O FADH2 FAD NADH NAD+ ADP + P ATP Figure 9.16 Chemiosmosis couples the electron transport chain to ATP synthesis i (carrying electrons from food) H+ 1 Electron transport chain 2 Chemiosmosis Oxidative phosphorylation

World’s smallest motor: Fig. 9-14 INTERMEMBRANE SPACE H+ Stator World’s smallest motor: ATP synthetase Rotor Internal rod Figure 9.14 ATP synthase, a molecular mill Cata- lytic knob ADP + P ATP i MITOCHONDRIAL MATRIX

Aerobic respiration bioflix

Electrons carried via NADH Electrons carried via NADH and FADH2 Fig. 9-6-3 Electrons carried via NADH Electrons carried via NADH and FADH2 Oxidative phosphorylation: electron transport and chemiosmosis Glycolysis Citric acid cycle Glucose Pyruvate Mitochondrion Cytosol Figure 9.6 An overview of cellular respiration ATP ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation

BioFlix: Cellular Respiration The process that generates most of the ATP is called oxidative phosphorylation because it is powered by redox reactions BioFlix: Cellular Respiration Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Glycolysis occurs in the cytoplasm and has two major phases: Concept 9.2: Glycolysis harvests chemical energy by oxidizing glucose to pyruvate Glycolysis (“splitting of sugar”) breaks down glucose into two molecules of pyruvate Glycolysis occurs in the cytoplasm and has two major phases: Energy investment phase Energy payoff phase Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Energy investment phase Fig. 9-8 Energy investment phase Glucose 2 ADP + 2 P 2 ATP used Energy payoff phase 4 ADP + 4 P 4 ATP formed 2 NAD+ + 4 e– + 4 H+ 2 NADH + 2 H+ Figure 9.8 The energy input and output of glycolysis 2 Pyruvate + 2 H2O Net Glucose 2 Pyruvate + 2 H2O 4 ATP formed – 2 ATP used 2 ATP 2 NAD+ + 4 e– + 4 H+ 2 NADH + 2 H+

In the presence of O2, pyruvate enters the mitochondrion Concept 9.3: The citric acid cycle completes the energy-yielding oxidation of organic molecules In the presence of O2, pyruvate enters the mitochondrion Before the citric acid cycle can begin, pyruvate must be converted to acetyl CoA, which links the cycle to glycolysis Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The citric acid cycle, also called the Krebs cycle, takes place within the mitochondrial matrix The cycle oxidizes organic fuel derived from pyruvate, generating 1 ATP, 3 NADH, and 1 FADH2 per turn Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Two common types are alcohol fermentation and lactic acid fermentation Types of Fermentation Fermentation consists of glycolysis plus reactions that regenerate NAD+, which can be reused by glycolysis Two common types are alcohol fermentation and lactic acid fermentation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

In alcohol fermentation, pyruvate is converted to ethanol in two steps, with the first releasing CO2 Alcohol fermentation by yeast is used in brewing, winemaking, and baking Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

In lactic acid fermentation, pyruvate is reduced to NADH, forming lactate as an end product, with no release of CO2 Lactic acid fermentation by some fungi and bacteria is used to make cheese and yogurt Human muscle cells use lactic acid fermentation to generate ATP when O2 is scarce Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings