* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Cellular Respiration - Cathedral High School
Amino acid synthesis wikipedia , lookup
Metalloprotein wikipedia , lookup
Biosynthesis wikipedia , lookup
Mitochondrion wikipedia , lookup
NADH:ubiquinone oxidoreductase (H+-translocating) wikipedia , lookup
Fatty acid synthesis wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Photosynthesis wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Nicotinamide adenine dinucleotide wikipedia , lookup
Phosphorylation wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Butyric acid wikipedia , lookup
Electron transport chain wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Microbial metabolism wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
Oxidative phosphorylation wikipedia , lookup
BIOLOGY Chapter 8: pp. 133-149 10th Edition Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. NADH e– Insert figure 8.2 here NADH e– e– e– Cytoplasm e– NADH and FADH2 e– Glycolysis glucose Mitochondrion e– Citric acid cycle Preparatory reaction pyruvate Sylvia S. Mader Cellular Respiration Electron transport chain and chemiosmosis 2 ADP 2 ADP 4 ATP total 4 ADP 2 ATP net gain 2 ADP 2 ATP 32 ADP or 34 32 or 34 ATP PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor Copyright © The McGraw Hill Companies Inc. Permission required for reproduction or display 1 Connection between Photosynthesis and Respiration Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings STAGES OF CELLULAR RESPIRATION AND FERMENTATION Fermentation = anaerobic Cellular respiration = aerobic • Cellular respiration oxidizes sugar and produces ATP in 3-4 main stages: Glycolysis, Prep (Transition) Stage, Kreb’s (Citric Acid) Cycle, ETC • Fermentation oxidizes sugar and does not produce ATP, but yields a constant supply of NAD+ (an electron carrier) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Glucose Breakdown: Summary Reaction Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Oxidation C6H12O6 + 6O2 6CO2 + 6H2O + energy glucose Reduction Electrons are removed from substrates and received by oxygen, which combines with H+ to become water. Glucose is oxidized and O2 is reduced 4 NAD+ and FAD NAD+ (nicotinamide adenine dinucleotide) Called a coenzyme of oxidation-reduction. It can: Oxidize a metabolite by accepting electrons Reduce a metabolite by giving up electrons Each NAD+ molecule used over and over again FAD (flavin adenine dinucleotide) Also a coenzyme of oxidation-reduction Sometimes used instead of NAD+ Accepts two electrons and two hydrogen ions (H+) to become FADH2 5 Cellular Respiration Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. O2 and glucose enter cells, which release H2O and CO2. H2 O CO2 intermembrane space cristae Mitochondria use energy from glucose to form ATP from ADP + P . ADP + P ATP © E. & P. Bauer/zefa/Corbis; (Bread, wine, cheese, p. 139): © The McGraw Hill Companies, Inc./John Thoeming, photographer; (Yogurt, p. 139): © The McGraw Hill Companies, Inc./Bruce M. Johnson, photographer 6 ATP Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phases of Cellular Respiration Cellular respiration includes four phases: Glycolysis is the breakdown of glucose into two molecules of pyruvate Occurs in cytoplasm ATP is formed Does not utilize oxygen Transition (preparatory) reaction Both pyruvates are oxidized and enter mitochondria Electron energy is stored in NADH Two carbons are released as CO2 (one from each pyruvate) 7 Phases of Cellular Respiration Citric acid cycle Occurs in the matrix of the mitochondrion and produces NADH and FADH2 In series of reaction releases 4 carbons as CO2 Turns twice (once for each pyruvate) Produces two immediate ATP molecules per glucose molecule Electron transport chain Extracts energy from NADH & FADH2 Passes electrons from higher to lower energy states Produces 32 molecules of ATP 8 Glucose Breakdown: Overview of 4 Phases Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display NADH e– e– NADH e– e– Cytoplasm e– NADH and FADH2 e– Glycolysis glucose Mitochondrion e– Citric acid cycle Preparatory reaction pyruvate Electron transport chain and chemiosmosis 2 ATP 2 ATP 4 ATP total 4 ADP 2 ATP net gain 2 ADP 2 ATP 32 ADP or 34 32 or 34 ATP 9 Glucose Breakdown: Glycolysis Occurs in cytoplasm outside mitochondria Energy Investment Steps: Two ATP are used to activate glucose Glucose splits into two G3P molecules Energy Harvesting Steps: Oxidation of G3P occurs by removal of electrons and hydrogen ions Two electrons and one hydrogen ion are accepted by NAD+ resulting two NADH Four ATP produced by phosphorylation Net gain of two ATP Both G3Ps converted to pyruvates 10 First phase in aerobic respiration is GLYCOLYSIS….no oxygen involved in this phase Glycolsis Glucose Pyruvate Mitochondrion ATP Substrate-level phosphorylation Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings • Details of glycolysis... ...Do we need to know that??!! Steps 1 – 3 A fuel molecule is energized, using ATP. Glucose Step PREPARATORY PHASE (energy investment) 1 Glucose-6-phosphate 2 Fructose-6-phosphate 3 Step 4 A six-carbon intermediate splits into two three-carbon intermediates. Step 5 A redox reaction generates NADH. Fructose-1,6-diphosphate 4 Glyceraldehyde-3-phosphate (G3P) 6 Steps 6– 9 ATP and pyruvic acid are produced. ENERGY PAYOFF PHASE 5 1,3-Diphosphoglyceric acid (2 molecules) 7 3-Phosphoglyceric acid (2 molecules) 8 2-Phosphoglyceric acid (2 molecules) 2-Phosphoglyceric acid (2 molecules) 9 Figure 6.9B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Pyruvic acid (2 molecules per glucose molecule) GLYCOLYSIS BASICS http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html Glucose Figure 6.9A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Pyruvic acid Glycolysis: Inputs and Outputs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display inputs Glycolysis outputs glucose 2 pyruvate 2 NADH 2 NAD+ 2 ATP 2 ADP 4 ADP + 4 P 4 ATP total 2 ATP net gain 11 Pyruvate Pyruvate is a pivotal metabolite in cellular respiration If O2 is not available to the cell, fermentation, an anaerobic process, occurs in the cytoplasm. During fermentation, glucose is incompletely metabolized to lactate, or to CO2 and alcohol (depending on the organism). If O2 is available to the cell, pyruvate enters mitochondria by aerobic process. 16 Fermentation An anaerobic process that reduces pyruvate to either lactate or alcohol and CO2 NADH passes its electrons to pyruvate Alcoholic fermentation, carried out by yeasts, produces carbon dioxide and ethyl alcohol Lactic acid fermentation, carried out by certain bacteria and fungi, produces lactic acid (lactate) Used in the production of alcoholic spirits and breads. Used commercially in the production of cheese, yogurt, and sauerkraut. Other bacteria produce chemicals anaerobically, including isopropanol, butyric acid, proprionic acid, and acetic acid. 17 Fermentation is an anaerobic alternative to aerobic respiration • Under anaerobic conditions, many kinds of cells can use glycolysis alone to produce small amounts of ATP – But a cell must have a way of replenishing NAD+ Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ALCOHOLIC FERMENTATION • In alcoholic fermentation, pyruvic acid is converted to CO2 and ethanol – This recycles NAD+ to keep glycolysis working released GLYCOLYSIS Glucose 2 Pyruvic acid Figure 6.15A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 2 Ethanol Figure 6.15C LACTIC ACID FERMENTATION • In lactic acid fermentation, pyruvic acid is converted to lactic acid – As in alcoholic fermentation, NAD+ is recycled • Lactic acid fermentation is used to make cheese and yogurt GLYCOLYSIS Glucose 2 Pyruvic acid Figure 6.15B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 2 Lactic acid Efficiency of Fermentation Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fermentation inputs glucose 2 ADP + 2 P 2 outputs 2 lactate or 2 alcohol and 2 CO2 ATP net gain 25 Pyruvic acid is chemically groomed for the Krebs cycle in the Transition or Prep Stage • Each pyruvic acid molecule is broken down to form CO2 and a two-carbon acetyl group, which enters the Krebs cycle Pyruvic acid Acetyl CoA (acetyl coenzyme A) CO2c Figure 6.10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Aerobic Respiration Continues in the Mitochondria Glycolsis Glucos e Citric acid cycle Pyruvate Mitochondrion ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Details of the Kreb’s Cycle……. Do we need to know all that???? Answer: Yes and No 2 carbons enter cycle Oxaloacetic acid 1 Citric acid CO2 leaves cycle 5 KREBS CYCLE 2 Malic acid 4 Alpha-ketoglutaric acid 3 CO2 leaves cycle Succinic acid Step 1 Acetyl CoA stokes the furnace Steps 2 and 3 NADH, ATP, and CO2 are generated during redox reactions. Figure 6.11B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Steps 4and 5 Redox reactions generate FADH2 and NADH. Let’s look at a simplified version of the Kreb’s Cycle first….. The Krebs cycle completes the oxidation of glucose, generating many NADH and FADH2 molecules The Krebs cycle is a series of reactions in which enzymes strip away electrons and H+ from each acetyl group What are the products of the Kreb’s cycle? Figure 6.11A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Acetyl CoA KREBS CYCLE 2 CO2 KREB’S CYCLE aka Citric Acid Cycle…….times 2….WHY? http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__how_the_krebs_cycle_works__quiz_2_ .html Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Oxidative Phosphorylation = ETC plus Chemiosmosis Electrons carried via NADH Electrons carried via NADH and FADH2 Citric acid cycle Glycolsis Glucose Pyruvate Oxidative phosphorylation: electron transport and chemiosmosis Mitochondrion ATP Substrate-level phosphorylation Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ATP Substrate-level phosphorylation ATP Oxidative phosphorylation Chemiosmosis powers most ATP production http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__electron_transport_system_and_atp_synthesis__quiz_2_.html • The electrons from NADH and FADH2 travel down the electron transport chain (slowly losing energy). They will be grabbed by oxygen • Energy released by the electrons is used to pump H+ into the space between the mitochondrial membranes • In chemiosmosis, the H+ ions diffuse back through the inner membrane through ATP synthase complexes, which capture the energy to make ATP Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Therefore, the two mechanisms that generate ATP are ETC and Chemiosmosis • Cells use the energy released by “falling” electrons to pump H+ ions across a membrane – The energy of the gradient is harnessed to make ATP by the process of chemiosmosis High H+ concentration Membrane Electron transport chain ATP synthase Energy from Low H+ concentration Figure 6.7A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ATP synthase uses graient energy to make ATP Overview of Cellular Respiration (Aerobic) 6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings INTERCONNECTIONS BETWEEN MOLECULAR BREAKDOWN AND SYNTHESIS Cells use many kinds of organic molecules as fuel for cellular respiration • Polysaccharides can be hydrolyzed to monosaccharides and then converted to glucose for glycolysis • Proteins can be digested to amino acids, which are chemically altered and then used in the Krebs cycle • Fats are broken up and fed into glycolysis and the Krebs cycle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings • Pathways of molecular breakdown Food, such as peanuts Polyscaccharides Fats Proteins Sugars Glycerol Fatty acids Amino acids Amino groups Glucose G3P Pyruvic acid Acetyl CoA GLYCOLYSIS Figure 6.16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings KREBS CYCLE ELECTRON TRANSPORT CHAIN AND CHEMIOSMOSIS The fuel for respiration ultimately comes from photosynthesis • All organisms have the ability to harvest energy from organic molecules – Plants, but not animals, can also make these molecules from inorganic sources by the process of photosynthesis (Chapter 7) Figure 6.18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings