Presentation is loading. Please wait.

Presentation is loading. Please wait.

Energy Releasing Pathways ATP

Similar presentations

Presentation on theme: "Energy Releasing Pathways ATP"— Presentation transcript:

1 Energy Releasing Pathways ATP

2 Aerobic Respiration A redox process
Glucose contains energy that can be converted to ATP Uses oxygen therefore aerobic

3 Cellular Energy Transfer
Cells transfer energy by redox reactions Remember: oxidation is the loss of electrons reductions is the gain of electrons Oxidation involves loss of energy Reduction involves the gain of energy


5 Aerobic Respiration- Redox
C6H12O6 + 6 O2 + 6 H2O  6 CO H2O + Energy Water is both a reactant and a product Glucose is oxidized to form CO2 Oxygen is reduced, forming water The electrons produced are used to form ATP oxidation reduction

6 Aerobic Respiration- 4 Stages
                                Glycolysis Formation of acetyl coenzyme A Citric Acid Cycle Electron transport system and chemiosmosis

7 Glycolysis Glucose is converted to 2 3-carbon molecules of pyruvate
ATP and NADH are formed Occurs in the cytosol Yellow- products Green- reactants

8 Glycolysis Pyruvate Yield
Glycolysis means “sugar splitting” One 6-carbon molecule is converted to two 3-carbon molecules Occurs in cytosol Occurs in both aerobic and anaerobic conditions A series of reactions; each catalyzed by a different enzyme Glucose yields two pyruvates



11 Glycolysis First phase requires ATP investment 2 ATPs used G3P

12 Glucose Fructose- 1,6-diphosphate 2 glyceraldehyde-3-phosphate (G3P)
PHASE 1 Glucose 2 ATPs used Fructose- 1,6-diphosphate 2 glyceraldehyde-3-phosphate (G3P)

13 Glycolysis Second phase yields NADH and ATP

14 PHASE 2 G3P Pyruvate G3P Pyruvate + 2 NADH + 4 ATP


16 Pyruvate to acetyl CoA A carboxyl group is removed from pyruvate (carbon dioxide is produced) NADH is produced acetyl group joins with coenzyme A forming acetyl CoA Coenzyme A is made from pantothenic acid

17 Pyruvate Coenzyme A + NADH + CO2 acetyl CoA

18 Glycolysis acetyl CoA Krebs Cycle


20 Acetyl Coenzyme A Pyruvate is converted into acetyl CoA
NADH is produced Carbon dioxide is a waste product Occurs in the mitochondria Yellow- products Green- reactants




24 2 pyruvate + 2 NAD+ + 2 CoA ----> 2 acetyl CoA + 2 NADH +
2 carbon dioxide

25 Citric Acid Cycle Oxidizes acetyl CoA Also known as Krebs cycle
Occurs in mitochondria (matrix) Series of steps ultimately reforming oxaloacetate All of the energy of glucose is carried by NADH and FADH2

26 Citric Acid Cycle Acetyl CoA combines with oxaloacetate, forming citrate Citrate undergoes conversions, ultimately re-forming exaloacetate Carbon dioxide is a waste product ATP, NADH, and FADH2 are produced

27 Acetyl CoA oxaloacetate + 6 NADH + 2 FADH2 + 2 ATP

28 One Turn of Citric Acid Cycle*
2C molecule enters the cycle & joins a 4C molecule. In a series of steps, the remaining H and high energy e- are removed from the 2C. 3 NAD+ are converted into 3 NADH & 3H+. 1 FAD is converted into 1 FADH2. 1 ATP is made. 2 CO2 are released. At the end of the cycle, nothing remains of the original glucose molecule. * remember…this is x2!









37 Types of Reactions Dehydrogenation Decarboxylations
Hydrogens are transferred to a coenzyme (NAD+ or FAD) Decarboxylations Carboxyl groups are removed from the substrate as carbon dioxide Preparation reactions molecules are rearranged in preparation for decarboxylations or dehydrogenations

38 Electron Transport System Chemiosmosis
Electrons that originated in glucose are transferred via NADH and FADH2 to a chain of electron acceptors Hydrogen ions are pumped across the inner mitochondrial membrane ATP is produced by chemiosmosis

39 Electron Transport Chain
Coupled to ATP synthesis Transports e- from NADH and FADH2 to O2 Electrons  FMN  a series of cytochromes and coenzyme Q

40 Electron Carriers Most electron carriers carry hydrogen atoms
Electron carriers transfer energy Electrons lose energy as they are transferred between acceptors NAD+ is a common hydrogen acceptor is respiratory and photosynthetic pathways Nicotinamide adenine dinucleotide

41 Electron Carriers Nicotine adenine dinucleotide phosphate (NADP+) is involved in photosynthesis


43 NAD+ is a coenzyme derived from the vitamin nicotinic acid (niacin)

44 Electron Carriers Flavin Adenine Dinucleotide- FAD+ is involved in cellular respiration


46 Electron Carriers Cytochromes- proteins containing iron



49 Electron Transport Chain
Electrons lose energy as they pass through the chain

50 Electron Transport Chain
Hydrogen ions (protons) are passed into the intermembrane space of the mitochondria

51 Electron Transport Chain
Electrons are finally passed to oxygen thereby forming water

52 NADH 2H+ FMN Complex I 2H+ Q FADH2 cyt b 2H+ Complex II cyt cr cyt c O2 H2O cyt a cyt a3 Complex III





57 Chemiosmotic Model Peter Mitchell
1978 Nobel Prize in Chemistry for a 1961 paper on the chemiosmotic model Cornwall, UK Glynn Research Laboratories Died in 1992 Peter Mitchell

58 Chemiosmotic model Explains the coupling of ATP synthesis to electron transport A proton gradient is formed across the inner mitochondrial membrane

59 Chemiosmotic Model Protons diffuse through the channels formed by the enzyme complex ATP synthase Movement of protons catalyze production of ATP


61 http://telstar. ote. cmu. edu/biology/animation/ATPSynthesis/biochem


63 Energy Yield Efficiency is about 40%; the rest is disseminated as heat
Maximum yield of ATPs from NADH- 3 ATP from FADH2- 2 ATP The NADHs from glycolysis produce fewer ATPs due to the necessity of transport of NADH across the mitochondrial membrane

64 Energy Yield The NADHs from glycolysis produce fewer ATPs due to the necessity of transport of NADH across the mitochondrial membrane 36 to 38 ATPs yield

65 ATP produced GLUCOSE

66 2 ATP GLUCOSE 2 ATP produced directly GLYCOLYSIS

67 38 ATP 16 ATP 34 ATP 8 ATP 14 ATP 2 ATP 2 NADH 2 NADH 6 NADH 2 FADH2
GLUCOSE 2 ATP produced directly GLYCOLYSIS 6 ATP through electron transport + 2 NADH PYRUVIC ACID 6 ATP through electron transport + 2 NADH 2 ATP produced directly + ACETYL CoA 18 ATP through electron transport + KREBS CYCLE 6 NADH 4 ATP through electron transport + 2 FADH2

68 Other Nutrients Nutrients other that glucose provide energy
Humans gain more energy from oxidation of fatty acids than glucose Lipids contain 9 kcal per gram Lipids are broken down and glycerol enters glycolysis; fatty acids are converted to acetyl CoA and enter the citric acid cycle

69 Other Nutrients Proteins are broken down into amino acids
Amino acids are deaminated (the amino acids are removed) The remaining carbon chain centers at various points Proteins contain about 4 kcal per gram

70 Regulation of Aerobic Respiration
ATP synthesis continues until ADP stores are depleted Enzyme regulation is important An important regulation point is phosphofructokinase

71 PFK is activated by ADP/AMP
PFK is the committed step in glycolysis. Once this step is done then glycolysis will carry through. PFK is inhibited by ATP low pH citrate groups PFK is activated by ADP/AMP

72 Anaerobic Respiration
Various inorganic substances serve as the final electron acceptor like sulfur Yield is only the two ATP molecules from glycolysis Seen is some bacteria

73 Alcoholic Fermentation
Produces ethanol Pyruvate is converted to ethanol to regenerate NAD+ Ethanol is a potentially toxic waste product Yeast carry out alcoholic fermentation when oxygen deprived


75 Lactate Fermentation Bacteria and some fungi carry out lactate fermentation Pyruvate is converted to lactate to regenerate NAD+ Strenuous exercise in mammals results in lactate fermentation as well



78 Must Know...

79 http://micro. magnet. fsu

Download ppt "Energy Releasing Pathways ATP"

Similar presentations

Ads by Google