Chapter 6 How cells harvest chemical energy Musebio101 summer 2010.

Chapter 6 How cells harvest chemical energy Musebio101 summer 2010

Photosynthesis and cellular respiration provide energy for life
Energy is necessary for life processes These include growth, transport, manufacture, movement, reproduction, and others Energy that supports life on Earth is captured from sun rays reaching Earth through plant, algae, protist, and bacterial photosynthesis During photosynthesis, light energy is converted to chemical energy. Student Misconceptions and Concerns 1. Students should be cautioned against the assumption that energy is created when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics addressed in Module 5.11). Teaching Tips 1. You might wish to elaborate on the amount of solar energy striking Earth. Every day Earth is bombarded with solar radiation equal to the energy of 100 million atomic bombs. Of the tiny fraction of light that reaches photosynthetic organisms, only about 1% is converted to chemical energy by photosynthesis. 2. Energy coupling at the cellular level may be new to many students, but it is a familiar concept when related to the use of money in our society. Students might be discouraged if the only benefit of work was the ability to make purchases from the employer. (We all might soon tire of a fast-food job that only paid its employees in food!) Money permits the coupling of a generation of value (a paycheck, analogous to an energy-releasing reaction) to an energy-consuming reaction (money, which allows us to make purchases in distant locations). This idea of earning and spending is a common concept we all know well.

Sunlight energy Photosynthesis in chloroplasts + + (for cellular work)
ECOSYSTEM Photosynthesis in chloroplasts CO2 Glucose + + H2O O2 Cellular respiration in mitochondria Figure 6.1 The connection between photosynthesis and cellular respiration. ATP (for cellular work) Heat energy

Cellular respiration banks energy in ATP molecules
Cellular respiration is an exergonic process that transfers energy from the bonds in glucose to ATP Cellular respiration produces 38 ATP molecules from each glucose molecule Other foods (organic molecules) can be used as a source of energy as well Respiration only retrieves 40% of the energy in a glucose molecule. The other 60% of the energy is released as heat. We use this heat to maintain a relatively steady body temperature near 37°C (98–99°F). This is about the same amount of heat generated by a 75-watt incandescent light bulb. Organic compounds possess potential energy as a result of their arrangement of atoms. Compounds that can participate in exergonic reactions can act as food. Actually, cellular respiration includes both aerobic and anaerobic processes. However, it is generally used to refer to the aerobic process. It takes about 10 million ATP molecules per second to power one active muscle cell. Student Misconceptions and Concerns 1. Students should be cautioned against the assumption that energy is created when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics addressed in Module 5.11). 2. Students often fail to realize that aerobic metabolism is a process generally similar to the burning of wood in a fireplace or campfire or the burning of gasoline in an automobile engine. Noting these general similarities can help students comprehend the overall reaction and heat generation associated with these processes. Teaching Tips 1. Energy coupling at the cellular level may be new to many students, but it is a familiar concept when related to the use of money in our society. Students might be discouraged if the only benefit of work was the ability to make purchases from the employer. (We all might soon tire of a fast-food job that only paid its employees in food!) Money permits the coupling of a generation of value (a paycheck, analogous to an energy-releasing reaction) to an energy-consuming reaction (money, which allows us to make purchases in distant locations). This idea of earning and spending is a common concept we all know well. 2. During cellular respiration, our cells convert about 40% of our food energy to useful work. The other 60% of the energy is released as heat. We use this heat to maintain a relatively steady body temperature near 37°C (98–99°F). This is about the same amount of heat generated by a 75-watt incandescent lightbulb. If you choose to include a discussion of heat generation from aerobic metabolism, consider the following. A. Ask your students why they feel warm when it is 30°C (86°F) outside, if their core body temperature is 37°C (98.6°F). Shouldn’t they feel cold? The answer is, our bodies are always producing heat. At these higher temperatures, we are producing more heat than we need to maintain a body temperature around 37°C. Thus, we sweat and behave in ways that helps us get rid of the extra heat from cellular respiration. B. Share this calculation with your students. Depending upon a person’s size and level of activity, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100°C. This is something to think about the next time you heat water on the stove! (Notes: Consider bringing a 2-liter bottle as a visual aid, or ten 2-liter bottles to make the point above. It takes 100 calories to raise 1 liter of water 100°C; it takes much more energy to melt ice or evaporate water as steam.)

Introduction to Metabolism
Cells break down organic molecules to obtain energy Used to generate ATP Most energy production takes place in mitochondria

Metabolism Metabolism – refers to all chemical reaction occurring in body Catabolism – break down complex molecules Exergonic – produce more energy than they consume Anabolism – combine simple molecules into complex ones Endergonic – consume more energy than they produce Adenosine triphosphate (ATP) “energy currency” ADP + P + energy ↔ ATP

Amount of energy released
Reactants Amount of energy released Potential energy of molecules Energy released Products Figure 5.12A Exergonic reaction, energy released.

Metabolism Catabolism Anabolism Is the breakdown of organic substrates
Releases energy used to synthesize high-energy compounds (e.g., ATP) Anabolism Is the synthesis of new organic molecules

Cellular respiration is a catabolic reaction
C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATPs Glucose Oxygen Carbon dioxide Water Energy Figure 6.3 Summary equation for cellular respiration: C6H12O6 + 6 O2 6 CO2 + H2O + energy

Energy for cellular work
Fuel Energy conversion Waste products Heat Cellular respiration Glucose Carbon dioxide Figure 5.11 Energy transformations (with an increase in entropy) in a cell. Oxygen Water Energy for cellular work Energy conversion in a cell

Phosphorylation Hydrolysis
Energy from exergonic reactions Energy for endergonic reactions Figure 5.13C The ATP cycle.

Role of ATP in linking anabolic and catabolic reactions

Adenosine Triphosphate (ATP) Phosphate group Adenine Ribose Hydrolysis
Figure 5.13A The structure and hydrolysis of ATP. The reaction of ATP and water yields ADP, a phosphate group, and energy. + Adenosine Diphosphate (ADP)

Table 6.4 Energy Consumed by Various Activities (in kcal).

Carbohydrate Metabolism
Mitochondrial Membranes Outer membrane Contains large-diameter pores Permeable to ions and small organic molecules (pyruvic acid) Inner membrane Contains carrier protein Moves pyruvic acid into mitochondrial matrix Intermembrane space Separates outer and inner membranes

Chemical energy (high-energy electrons)
Electron transport chain and oxidative phosphorylation Glycolysis Krebs cycle Pyruvic acid Glucose Mitochondrial cristae Mitochondrion Cytosol Via oxidative phosphorylation Via substrate-level phosphorylation During glycolysis, each glucose molecule is broken down into two molecules of pyruvic acid in the cytosol. 1 The pyruvic acid then enters the mitochondrial matrix, where the Krebs cycle decomposes it to CO2. During glycolysis and the Krebs cycle, small amounts of ATP are formed by substrate- level phosphorylation. 2 3 Energy-rich electrons picked up bycoenzymes are transferred to the electron transport chain, built into the cristae membrane. The electron transport chain carries out oxidative phosphorylation, which accounts for most of the ATP generated by cellular respiration. Figure 24.5

Cellular respiration begins with glycolysis

Glucose Breakdown Occurs in small steps Which release energy to convert ADP to ATP One molecule of glucose nets 36 molecules of ATP Glycolysis Breaks down glucose in cytosol into smaller molecules used by mitochondria Does not require oxygen: anaerobic reaction Aerobic Reactions Also called aerobic metabolism or cellular respiration Occur in mitochondria, consume oxygen, and produce ATP

Catalysis Enzyme Enzyme (a) Substrate-level phosphorylation

Figure 6.7C Details of glycolysis.
ENERGY INVESTMENT PHASE 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 Figure 6.7C Details of glycolysis. 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

Substrate level phosphorylation energy payout phase.

1, 3-Bisphosphoglyceric acid (2 molecules)
NADH HCOH C CH2O O COOH 2 2 ADP 1, 3-Bisphosphoglyceric acid (2 molecules) 3-Phosphoglyceric acid P Phosphofructokinase Dihydroxyacetone phosphate CH2OH Glyceraldehyde 3-phosphate H ADP Glucose (1 molecule) OH 4 1 3 5 6 Glucose 6-phosphate Fructose 6-phosphate OH2C Fructose 1, 6-bisphosphate ATP HO 7 2 NAD+ + 2 + 2H+ NADH HCOH C CH2O O COOH 2 2 ADP 1, 3-Bisphosphoglyceric acid (2 molecules) 3-Phosphoglyceric acid CH2OH HCO 2-Phosphoglyceric acid P Phosphofructokinase Dihydroxyacetone phosphate Glyceraldehyde 3-phosphate H ADP Glucose (1 molecule) OH 4 1 3 5 6 Glucose 6-phosphate Fructose 6-phosphate OH2C Fructose 1, 6-bisphosphate ATP HO 7 8 2 NAD+ + 2 + 2H+ NADH HCOH C CH2O O COOH 2 2 ADP 1, 3-Bisphosphoglyceric acid (2 molecules) 3-Phosphoglyceric acid CH2OH HCO 2-Phosphoglyceric acid CH2 Phosphoenolpyruvic acid P Phosphofructokinase Dihydroxyacetone phosphate Glyceraldehyde 3-phosphate H ADP Glucose (1 molecule) OH 4 1 3 5 6 Glucose 6-phosphate Fructose 6-phosphate OH2C Fructose 1, 6-bisphosphate ATP HO 7 8 9 2 NAD+ + 2 + 2H+ NADH 2 NAD+ + 2 HCOH C CH2O O COOH 2 2 ADP P 1, 3-Bisphosphoglyceric acid (2 molecules) 3-Phosphoglyceric acid CH2OH HCO 2-Phosphoglyceric acid Pyruvic acid CH2 Phosphoenolpyruvic acid CH 3 Phosphofructokinase Dihydroxyacetone phosphate Glyceraldehyde 3-phosphate H ADP Glucose (1 molecule) OH 4 1 5 6 Glucose 6-phosphate Fructose 6-phosphate OH2C Fructose 1, 6-bisphosphate ATP HO 7 8 9 10 + 2H+ NADH HCOH C CH2O O 1, 3-Bisphosphoglyceric acid (2 molecules) 2 P Phosphofructokinase Dihydroxyacetone phosphate CH2OH Glyceraldehyde 3-phosphate H ADP Glucose (1 molecule) OH 4 1 3 5 6 Glucose 6-phosphate Fructose 6-phosphate OH2C Fructose 1, 6-bisphosphate ATP HO 2 NAD+ + 2 Phosphofructokinase Dihydroxyacetone phosphate CH2OH CH2O C O Glyceraldehyde 3-phosphate HCOH H ADP Glucose (1 molecule) OH 4 1 3 2 5 6 Glucose 6-phosphate Fructose 6-phosphate OH2C Fructose 1, 6-bisphosphate P ATP HO Phosphofructokinase ADP O Glucose (1 molecule) CH2OH OH 4 1 3 2 5 6 Glucose 6-phosphate Fructose 6-phosphate H OH2C P ATP HO Phosphofructokinase ADP O Glucose (1 molecule) CH2OH OH 4 1 3 2 5 6 Glucose 6-phosphate Fructose 6-phosphate H OH2C CH2O Fructose 1, 6-bisphosphate P ATP HO ADP O Glucose (1 molecule) CH2OH OH 4 1 3 2 5 6 Glucose 6-phosphate OH2C P ATP H HO ADP O Glucose (1 molecule) CH2OH OH 4 1 3 2 5 6 ATP H HO

Fate of pyruvic acid

Glucose 2 ADP 2 NAD+  2 P 2 ATP 2 NADH 2 Pyruvate 2 NADH 2 CO2
GLYCOLYSIS 2 ATP 2 NADH 2 Pyruvate 2 NADH 2 CO2 released Figure 6.13B Alcohol fermentation oxidizes NADH to NAD+ and produces ethanol and CO2. 2 NAD+ 2 Ethanol Alcohol fermentation

Glycolysis evolved early in the history of life on Earth
Glycolysis is the universal energy-harvesting process of living organisms So, all cells can use glycolysis for the energy necessary for viability The fact that glycolysis has such a widespread distribution is good evidence for evolution Ancient prokaryotes probably used glycolysis to make ATP long before oxygen was present in Earth’s atmosphere. Student Misconceptions and Concerns 1. Perhaps more than anywhere else in general biology, students studying aerobic metabolism may fail to see the forest for the trees. Students may focus on the details of each stage of aerobic metabolism and devote little attention to the overall process and products. Consider emphasizing the products and energy yields associated with glycolysis, the citric acid cycle, and oxidative phosphorylation before detailing the specifics of each reaction. 2. The location within a cell in which each reaction takes place is often forgotten in the details of the chemical processes, but it is important to emphasize. Consider using Figure 6.12 as a common reference to locate each stage as you discuss the details of cellular respiration. 3. Students frequently think that plants have chloroplasts instead of mitochondria. Take care to point out the need for mitochondria in plants when photosynthesis is not efficient or possible (such as during the night). Teaching Tips 1. The widespread occurrence of glycolysis, which takes place in the cytosol and independent of organelles, suggests that this process had an early evolutionary origin. Since atmospheric oxygen was not available in significant amounts during the early stages of Earth’s history, and glycolysis does not require oxygen, it is likely that this chemical pathway was used by the prokaryotes in existence at that time. Students focused on the evolution of large, readily apparent structures such as wings and teeth may have never considered the evolution of cellular chemistry.

Oxidation and Reduction Oxidation (loss of electrons) Electron donor is oxidized Reduction (gain of electrons) Electron recipient is reduced The two reactions are always paired

Energy transfer Oxidation-reduction or redox reactions
Oxidation – removal of electrons Decrease in potential energy Dehydrogenation – removal of hydrogens Liberated hydrogen transferred by coenzymes Nicotinamide adenine dinucleotide (NAD) Flavin adenine dinucleotide (FAD) Glucose is oxidized Reduction – addition of electrons Increase in potential energy

The TCA Cycle (citric acid cycle) The function of the citric acid cycle is To remove hydrogen atoms from organic molecules and transfer them to coenzymes In the mitochondrion Pyruvic acid reacts with NAD and coenzyme A (CoA) Producing 1 CO2, 1 NADH, 1 acetyl-CoA Acetyl group transfers From acetyl-CoA to oxaloacetic acid Produces citric acid

CITRIC ACID CYCLE Acetyl CoA CoA CoA 2 CO2 3 NAD+ FADH2 FAD 3 NADH 
Figure 6.9A An overview of the citric acid cycle: Two carbons enter the cycle through acetyl CoA, and 2 CO2, 3 NADH, 1 FADH2, and 1 ATP exit the cycle. FAD 3 NADH  3 H+ ATP ADP + P

Mitochondrion (matrix)
Cytosol Glycolysis Krebs cycle Electron transport chain and oxidative phosphorylation Pyruvic acid from glycolysis NAD+ CO2 Transitional phase NADH+H+ Carbon atom Acetyl CoA Mitochondrion (matrix) Inorganic phosphate Coenzyme A Oxaloacetic acid Citric acid (pickup molecule) NADH+H+ (initial reactant) NAD+ Malic acid Isocitric acid NAD+ Krebs cycle CO2 NADH+H+ Fumaric acid -Ketoglutaric acid CO2 FADH2 NAD+ Succinic acid Succinyl-CoA NADH+H+ FAD GTP GDP + ADP

The TCA Cycle CoA is released to bind another acetyl group One TCA cycle removes two carbon atoms Regenerating 4-carbon chain Several steps involve more than one reaction or enzyme H2O molecules are tied up in two steps CO2 is a waste product The product of one TCA cycle is One molecule of GTP (guanosine triphosphate)

The Krebs Cycle

KREBS CYCLE KREBS CYCLE KREBS CYCLE KREBS CYCLE KREBS CYCLE KREBS
1 To electron transport chain CO2 + H+ NADH transport chain C CH2 COOH O Oxaloacetic acid H2C Succinic acid Succinyl CoA S CoA Alpha-ketoglutaric acid HCH Isocitric acid HOC HC H Citric acid Fumaric acid NAD+ GDP FAD CH Pyruvic acid Acetyl coenzyme A CH3 ADP FADH2 H2O KREBS CYCLE ATP GTP 2 3 4 5 6 1 To electron transport chain CO2 + H+ NADH transport chain C CH2 COOH O Oxaloacetic acid HCOH H2C Succinic acid Malic acid Succinyl CoA S CoA Alpha-ketoglutaric acid HCH Isocitric acid HOC HC H Citric acid Fumaric acid NAD+ GDP FAD CH Pyruvic acid Acetyl coenzyme A CH3 ADP FADH2 H2O KREBS CYCLE ATP GTP 2 3 4 5 6 7 1 To electron transport chain CO2 + H+ NADH transport chain C CH2 COOH O Oxaloacetic acid HCOH H2C Succinic acid Malic acid Succinyl CoA S CoA Alpha-ketoglutaric acid HCH Isocitric acid HOC HC H Citric acid Fumaric acid NAD+ GDP FAD CH Pyruvic acid Acetyl coenzyme A CH3 ADP FADH2 H2O KREBS CYCLE ATP GTP 2 3 4 5 6 7 8 1 To electron transport chain CO2 + H+ NADH C CH2 COOH O Oxaloacetic acid H2C Succinic acid Succinyl CoA S CoA Alpha-ketoglutaric acid HCH Isocitric acid HOC HC H Citric acid NAD+ GDP Pyruvic acid Acetyl coenzyme A CH3 ADP H2O KREBS CYCLE ATP GTP 2 3 4 5 1 To electron transport chain CO2 + H+ NADH C CH2 COOH O Oxaloacetic acid Succinyl CoA H2C S CoA Alpha-ketoglutaric acid HCH Isocitric acid HOC HC H Citric acid NAD+ Pyruvic acid Acetyl coenzyme A CH3 H2O KREBS CYCLE 2 3 4 1 C CH2 COOH O Oxaloacetic acid Isocitric acid H2C HOC HC H Citric acid + H+ Pyruvic acid Acetyl coenzyme A CH3 To electron transport chain H2O CO2 NAD+ KREBS CYCLE NADH CoA 2 1 To electron transport chain CO2 + H+ C CH2 COOH O Oxaloacetic acid Alpha-ketoglutaric acid H2C HCH Isocitric acid HOC HC H Citric acid NAD+ Pyruvic acid Acetyl coenzyme A CH3 H2O KREBS CYCLE NADH CoA 2 3 1 C CH2 COOH O Oxaloacetic acid Citric acid H2C HOC + H+ Pyruvic acid Acetyl coenzyme A CH3 To electron transport chain H2O CO2 NAD+ KREBS CYCLE NADH CoA

A Summary of the Energy Yield of Aerobic Metabolism.

Summary: The TCA Cycle (Krebs cycle) CH3CO - CoA + 3NAD + FAD + GDP + Pi + 2 H2O  CoA + 2 CO2 + 3NADH + FADH2 + 2 H+ + GTP

The Electron Transport System (ETS) Is the key reaction in oxidative phosphorylation Is in inner mitochondrial membrane Electrons carry chemical energy Within a series of integral and peripheral proteins

Coenzyme FAD Accepts two hydrogen atoms from TCA cycle: Gaining two electrons Coenzyme NAD Accepts two hydrogen atoms Gains two electrons Releases one proton Forms NADH + H+

1 3 1 3 1 1 NADH + 2 H+ GLYCOLYSIS CO2 FORMATION OF ACETYL COENZYME A
KREBS CYCLE + 6 H+ FADH2 2 4 6 ELECTRON TRANSPORT CHAIN e– 32 or 34 O2 H2O Electrons 2 Acetyl coenzyme A 2 Pyruvic acid 1 Glucose ATP 3 1 NADH + 2 H+ GLYCOLYSIS CO2 FORMATION OF ACETYL COENZYME A KREBS CYCLE + 6 H+ FADH2 2 4 6 2 Acetyl coenzyme A 2 Pyruvic acid 1 Glucose ATP 3 1 NADH + 2 H+ GLYCOLYSIS CO2 FORMATION OF ACETYL COENZYME A 2 2 Acetyl coenzyme A 2 Pyruvic acid 1 Glucose ATP 1 NADH + 2 H+ GLYCOLYSIS 2 2 Pyruvic acid 1 Glucose ATP

NADH ATP NAD+ + 2e– Controlled release of H+ energy for synthesis
of ATP H+ Electron transport chain Figure 6.5C In cellular respiration, electrons fall down an energy staircase and finally reduce O2. 2e– H+ 1  2 O2 H2O

Oxidative Phosphorylation.

NADH+H+ FADH2 Enzyme Complex II Enzyme Complex I Enzyme Complex III
Glycolysis Krebs cycle Electron transport chain and oxidative phosphorylation FADH2 Enzyme Complex II Enzyme Complex I Enzyme Complex III Free energy relative to O2 (kcal/mol) Enzyme Complex IV

The actions of the three proton pumps and ATP synthase in the inner membrane of mitochondria
Space between outer and inner mitochondrial membranes Inner mitochondrial membrane Mitochondrial matrix H+ channel NADH dehydrogenase complex: FMN and five Fe-S centers Cytochrome b-c1 complex: cyt b, cyt c1, and an Fe-S center Cytochrome oxidase complex: cyt a, cyt a3,and two Cu NAD 1 1/2 O2 e– H+ + – H2O Q Cyt c NADH + H+ 3 ADP + ATP synthase P ATP 1 2

High H+ concentration in
intermembrane space Membrane Proton pumps (electron transport chain) ATP synthase Energy from food ADP + Low H+ concentration in mitochondrial matrix (b) Oxidative phosphorylation

Overview of metabolic processes
Stage 1 Digestion in GI tract lumen to absorbable forms. Transport via blood to tissue cells. PROTEINS CARBOHYDRATES FATS Amino acids Glucose and other sugars Glycerol Fatty acids Stage 2 Anabolism (incorporation into molecules) and catabolism of nutrients to form intermediates within tissue cells. Proteins Glucose Glycogen Fats NH3 Pyruvic acid Acetyl CoA Stage 3 Oxidative breakdown of products of stage 2 in mitochondria of tissue cells. CO2 is liberated, and H atoms removed are ultimately delivered to molecular oxygen, forming water. Some energy released is used to form ATP. Krebs cycle Infrequent CO2 O2 Oxidative phosphorylation (in electron transport chain) H H2O

Summary of cellular respiration

Chemical energy (high-energy electrons)
Electron transport chain and oxidative phosphorylation Glycolysis Krebs cycle Pyruvic acid Glucose Mitochondrial cristae Mitochondrion Cytosol Via oxidative phosphorylation Via substrate-level phosphorylation During glycolysis, each glucose molecule is broken down into two molecules of pyruvic acid in the cytosol. 1 The pyruvic acid then enters the mitochondrial matrix, where the Krebs cycle decomposes it to CO2. During glycolysis and the Krebs cycle, small amounts of ATP are formed by substrate- level phosphorylation. 2 3 Energy-rich electrons picked up by coenzymes are transferred to the electron transport chain, built into the cristae membrane. The electron transport chain carries out oxidative phosphorylation, which accounts for most of the ATP generated by cellular respiration.

Food, such as peanuts Carbohydrates Fats Proteins Sugars Glycerol
Fatty acids Amino acids Amino groups Figure 6.15 Pathways that break down various food molecules. OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) CITRIC ACID CYCLE Acetyl CoA Glucose G3P Pyruvate GLYCOLYSIS ATP

Review Energy is harvested from high energy glucose by the mitochondria The process begins in the cytoplasm with glycolysis where glucose is converted to pyruvate The TCA cycle (Krebs cycle) harvests energy from the pyruvate and stores it as reduced electron carrier molecules The carrier molecules cash in these electrons for ATP in the electron transport chain if oxygen is available

Review (cont) 2 net ATP are made from each glucose in glycolysis
34 additional ATP are made from each glucose if oxygen is available to help run the TCA cycle and electron transport chain

Chapter 6 How cells harvest chemical energy Musebio101 summer 2010.

Similar presentations

Presentation on theme: "Chapter 6 How cells harvest chemical energy Musebio101 summer 2010."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Chapter 6 How cells harvest chemical energy Musebio101 summer 2010.

Similar presentations

Presentation on theme: "Chapter 6 How cells harvest chemical energy Musebio101 summer 2010."— Presentation transcript:

Similar presentations

About project

Feedback