* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Cellular Respiration: Harvesting Chemical Energy
Photosynthetic reaction centre wikipedia , lookup
Biosynthesis wikipedia , lookup
Metalloprotein wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Mitochondrion wikipedia , lookup
Electron transport chain wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Fatty acid synthesis wikipedia , lookup
Photosynthesis wikipedia , lookup
Specialized pro-resolving mediators wikipedia , lookup
Nicotinamide adenine dinucleotide wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Butyric acid wikipedia , lookup
Oxidative phosphorylation wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
Microbial metabolism wikipedia , lookup
Biochemistry wikipedia , lookup
Cellular Respiration: Harvesting Chemical Energy Respiration is the process of extracting stored energy from glucose and storing it in the high energy bonds of ATP. Cellular Respiration Equation Reactants C6H12O6 + 6 O2 Products 6 CO2 + 6 H2O and energy • As a result of respiration, energy is released from the chemical bonds and used for “phosphorylation” of ATP. • Phosphorylation is the process of adding a phosphate group to a molecule…. By adding a phosphate ADP it becomes ATP. • The respiration reactions are controlled by ENZYMES. Cellular Respiration • There are two types of Respiration: Anaerobic Respiration and Aerobic Respiration • Some organisms use the Anaerobic Respiration pathway, and some organisms use the Aerobic Respiration pathway. Anaerobes • Anaerobes are organisms that use the Anaerobic Respiration pathway • Most anaerobes are bacteria (not all). • Anaerobes do NOT require oxygen. Aerobes • Aerobes are organisms that use the Aerobic Respiration pathway. • Aerobes require oxygen. Anaerobic Respiration Anaerobic Respiration does NOT require oxygen! The 2 most common forms of Anaerobic Respiration are: 1. Alcoholic Fermentation, and 2. Lactic Acid Fermentation The First Stage of Respiration for ALL living organisms, anaerobes or aerobes, is called Glycolysis and takes place in the Cytosol. Glycolysis • glyco means “glucose/sugar”, and • lysis means “to split”. Therefore, • glycolysis means “to split glucose” • This process was likely used to supply energy for the ancient forms of bacteria. Glycolysis • Function - to split glucose and produce NADH, ATP and Pyruvate (pyruvic acid). • Location - Cytosol • Occurs in 9 steps- 6 of the steps use magnesium (Mg) as a cofactor. Glycolysis 4 ATP’s are produced Pyruvic Acid (3 Carbons) Glucose (6 carbons) 2 ATP’s supply the activation energy 2 NAD+ + 2 e- Pyruvic Acid (3 Carbons) 2 NADH 4 ATP Yield = 2 ATP Net Gain Products of Glycolysis • 2 Pyruvic Acids (a 3C acid) • 4 ATP • 2 NADH Alcoholic Fermentation is carried out by yeast, a kind of fungus. Alcoholic Fermentation • Uses only Glycolysis. • Does NOT require O2 • Produces ATP when O2 is not available. Alcoholic Fermentation (Ethyl Alcohol or Ethanol) C6H12O6 2 C2H5OH + 2 CO2 As a result of Alcoholic Fermentation, Glucose is converted into 2 molecules of Ethyl Alcohol and 2 Molecules of Carbon Dioxide. Alcoholic Fermentation Glycolysis Released into the environment 4 ATP’s are produced CO2 (C2H5OH) Ethyl Alcohol (2C) Pyruvic Acid (3C) Released into the environment Glucose (6 carbons) 2 ATP’s supply the activation energy 2 NAD+ + 2 e- CO2 Pyruvic Acid (3C) 2 NADH Ethyl Alcohol (2C) (C2H5OH) 2 NAD+ + 2 e- 4 ATP Yield = 2 ATP Net Gain Question • Why is the alcohol content of wine always around 12-14%? • Because Alcohol is toxic and kills the yeast at high concentrations. Oh Yeah…..The Holes in Swiss Cheese are bubbles of CO2 from fermentation. Importance of Fermentation • Alcohol Industry - almost every society has a fermented beverage. • Baking Industry - many breads use yeast to provide bubbles to raise the dough. Lactic Acid Fermentation • Uses only Glycolysis. • Does NOT require O2 • Produces ATP when O2 is not available. Lactic Acid Fermentation • Carried out by human muscle cells under oxygen debt. • Lactic Acid is a toxin and causes fatigue, soreness and stiffness in muscles. Lactic Acid Fermentation Glycolysis 4 ATP’s are produced Pyruvic Acid (3C) Lactic Acid (3C) Pyruvic Acid (3C) Lactic Acid (3C) Glucose (6 carbons) 2 ATP’s supply the activation energy 2 NAD+ + 2 e- 2 NADH 2 NAD+ + 2 e- 4 ATP Yield = 2 ATP Net Gain Fermentation - Summary • Releases 2 ATP from the breakdown of a glucose molecule • Provides ATP to a cell even when O2 is absent. Aerobic Respiration Aerobic Respiration requires oxygen! There are three phases to Aerobic Respiration ... they are: 1. Glycolysis (same as the glycolysis of anaerobic respiration) 2. Krebs cycle (AKA - Citric Acid cycle) 3. Oxidative Phosphorylation and The Electron Transport Chain Phase One: Glycolysis (takes place in the cytoplasm) Glycolysis 4 ATP’s are produced Pyruvic Acid (3C) Glucose (6 carbons) 2 ATP’s supply the activation energy 2 NAD+ + 2 e- Pyruvic Acid (3C) 2 NADH 4 ATP Yield = 2 ATP Net Gain In order for Aerobic Respiration to continue the Pyruvic acid is first converted to Acetic Acid by losing a carbon atom and 2 oxygens as CO2. The Acetic acid then must enter the matrix region of the mitochondria. The CO2 produced is the CO2 animals exhale when they breathe. Phase Two: The Krebs Cycle (AKA the Citric Acid Cycle) Once the Acetic Acid enters the Matrix it combines with Coenzyme A to form a new molecule called Acetyl-CoA. The Acetyl-CoA then enters the Krebs Cycle. Sir Hans Adolf Krebs Produces most of the cell's energy in the form of NADH and FADH2… not ATP Does NOT require O2 CoA breaks off to gather more acetic acid. The Acetic acid is broken down. + 3H 3 NADH Summary As a result of one turn of the Krebs cycle the cell makes: 1 FADH2 3 NADH 1 ATP However, each glucose produces two pyruvic acid molecules…. So the total outcome is: 2 FADH2 6 NADH 2 ATP Comparing Aerobic and Anaerobic Respiration • Aerobic Respiration–requires a mitochondrion and oxygen –is a three phase process • Anaerobic – –does not require oxygen –consists of one phase only-Glycolysis Strict vs. Facultative Respiration • Strict - can only carry out Respiration only one way… aerobic or anaerobic. Ex - you • Facultative - can switch respiration types depending on O2 availability. Ex – yeast • Aerobes – organisms that require oxygen • Anaerobes - organisms that DO NOT require oxygen • Obligate Anaerobes – oxygen is LETHAL to these organisms • Facultative – organisms that can live with or without oxygen ATP Sum • 10 NADH x 3 = 30 ATPs • 2 FADH2 x 2 = 4 ATPs • 2 ATPs (Gly) = 2 ATPs • 2 ATPs (Krebs) = 2 ATPs • Max = 38 ATPs per glucose However... Some energy (2 ATP’s) is used to shuttle the NADH from Glycolysis into the mitochondria…..So, some biologists teach there is an actual ATP yield of 36 ATP’s per glucose.