Biochemistry 1. The food we eat, (carbohydrates/glucose/sugar, - PDF document

9/14/16 OVERVIEW OF ENERGY AND METABOLISM Biochemistry 1. The food we eat, (carbohydrates/’glucose’/sugar, lipids/fat, proteins), are our only source of energy 5. Bio-Energetics & ATP for doing the biological work of cells. 2. All molecules (nutrient molecules included) have 5.1) ADP, ATP and Cellular Respiration stored (potential) energy in the bonds between their atoms. 3. The energy that runs most biological systems on earth comes from solar energy 4. Plants trap solar energy via the metabolic reactions of Photosynthesis by producing these molecules Prof. Dr. Klaus Heese 1 Intestine When a person eats, blood glucose rises. MAIN INTAIN ININ ING 2 Pancreas High blood glucose stimulates BLOOD BL the pancreas to release insulin. Insulin GLUCOS GL OSE 3 Insulin stimulates the uptake of glucose into cells and storage HOMEOSTASIS IS as glycogen in the liver and Liver muscles. Insulin also stimulates the conversion of excess glucose into fat for storage. Fat cell Muscle 4 As the body's cells use glucose, blood levels decline. 5 Pancreas Low blood glucose stimulates the pancreas to release Glucagon glucagon into the bloodstream. 6 Glucagon stimulates liver cells to break down glycogen Glucose and release glucose into the Insulin blood. a Glucagon Liver Glycogen a The stress hormone 7 epinephrine and other hormones Blood glucose begins to also bring glucose out of storage. rise. THREE BASIC USES OF NUTRIENTS ALL LIVING THINGS FROM BACTERIA TO ABSORBED BY THE DIGESTIVE SYSTEM HUMANS CONDUCT METABOLISM Metabolism is the ability to acquire and use energy from 1. Energy for immediate use by cells to conduct their the environment. normal metabolic processes (Muscle contraction, Metabolic processes are all the chemical reactions secretions, active transport) that occur in cells, tissues, organs, and organ systems. 2. Synthesize structural or functional molecules to Two Kinds of Metabolic Reactions: repair and replace cells. (Mitosis and Cytokinesis) 1. Catabolism = breakdown of large molecules into simple ones to produce energy (release energy). 3. Storage as glycogen or fat for later use as energy (nutrient reserves) 2. Anabolism = build large molecules from simple molecules (requires energy input). 1

9/14/16 TW TWO BASIC KINDS OF CHEMICAL RE REAC ACTI TIONS METABOLIC TURNOVER AND CELLULAR ATP FO FOUND IN BIOLOGICAL SYSTEM PRODUCTION CHEMICAL STRUCTURE OF ATP WHAT IS ATP? Adenine Base Energy used by all Cells Adenosine Triphosphate Organic molecule containing high- energy Phosphate bonds 3 Phosphates Ribose Sugar HOW DO WE GET ENERGY FROM ATP? WHAT DOES ATP DO FOR YOU? It supplies YOU with ENERGY! By breaking the high- energy bond between the last two phosphates in ATP 2

9/14/16 HOW DOES THAT HAPPEN? WHAT IS THE PROCESS CALLED? HYDROLYSIS (adding H 2 O) An Enzyme! H 2 O THE ADP-ATP CYCLE HOW IS ATP RE-MADE? The reverse of the previous process occurs. ATP ATP-ase Synthetase Another Enzyme is used! ATP Synthetase CELLULAR RESPIRATION WHEN IS ATP MADE IN THE BODY? l Includes pathways that require During a Process called: oxygen Cellular Respiration l Glucose is oxidized and O 2 is reduced l Glucose breakdown is therefore an oxidation-reduction reaction l Breakdown of one glucose results in or: oxidative phosphorylation 36 to 38 ATP molecules 3

9/14/16 OVERALL EQUATION FOR WHAT TYPE OF PROCESS IS CELLULAR RESPIRATION? CELLULAR RESPIRATION • An Oxidation-Reduction Process or C 6 H 12 O 6 + 6O 2 RedOx Reaction • Oxidation of GLUCOSE --> CO 2 + H 2 O (e - removed from C 6 H 12 O 6 ) YIELDS • Reduction of O 2 to H 2 O (e - passed to O 2 ) 6CO 2 + 6H 2 0 + e - + 36-38 ATP ’ s ARE THERE ANY OTHER ELECTRON WHAT CARRIES THE ELECTRONS? CARRIERS? NAD + (nicotinadenine • l YES! Another dinucleotide) acts as Coenzyme! the energy carrier l FAD+ (Flavin NAD + is a coenzyme • adenine • It is reduced to NADH dinucleotide) when it picks up two l Reduced to electrons and one FADH 2 hydrogen ion OTHER CELLULAR RESPIRATION FACTS WHAT ARE THE STAGES OF CELLULAR RESPIRATION? • Metabolic pathway that breaks down carbohydrates • Glycolysis • Process is exergonic as high-energy • The Krebs Cycle glucose is broken into CO 2 and H 2 O • The Electron Transport Chain • Process is also catabolic because larger glucose breaks into smaller molecules 4

9/14/16 Glycogenesis: SU SUMMARY OF F GLUCOSE SE METABOLISM SM The process by which glycogen is synthesized from glucose; in which glucose molecules are added to chains of glycogen for storage. Glycogenolysis: (also known as "Glycogenlysis") is the break down of glycogen to glucose-1-phosphate and glucose for ATP production. Gluconeogenesis (abbreviated GNG) is a metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as pyruvate, lactate, glycerol, and glucogenic amino acids; the process by which protein or fat is converted into glucose. OVERVIEW: OVERVIEW DIAGRAM OF THE PROCESS Occurs across Glycolysis Cristae Fat Occurs in Cytoplasm Occurs in Matrix GLYCOLYSIS SUMMARY GLYCOLYSIS SUMMARY Takes place in the Cytoplasm • Also produces 2 NADH and 4(2) ATP Anaerobic (doesn’t use Oxygen) • Pyruvate is oxidized to Acetyl CoA and CO 2 is Requires input of 2 ATP removed Glucose split into two molecules of Pyruvate or Pyruvic Acid 5

9/14/16 AT ATP PRODUCTION FROM CARBOHYDRAT ATES ATP PRODUCTION FROM CARBOHYDRAT AT ATES Glycolysis Formation of Acetyl-CoA Substrates required: Glucose, 2 ATP, 4 ADP, and 2 NAD + Substrates required: 2 Pyruvic Acid 2 NAD + Intermediate Reactants: Glucose-6-phosphate, Fructose-1,6 bisphosphate 2 Coenzyme A Products: 2 molecules of Pyruvic Acid Products: 2 Acetyl-CoA 2 ATP (4) 2 NADH 2 NADH 2 CO 2 FERMENTATION A LITTLE KREBS CYCLE HISTORY Ø Occurs when O 2 is NOT present • Discovered by Hans Krebs in 1937 (anaerobic) • He received the Ø Called Lactic Acid fermentation in Nobel Prize in physiology / muscle cells (makes muscles tired) medicine in 1953 for his discovery Ø Called Alcoholic fermentation in yeast • Forced to leave (produces ethanol) Germany prior to WWII because he Ø Nets only 2 ATP was Jewish ATP PRODUCTION FROM CARBOHYDRATES ATP PRODUCTION FROM CARBOHYDRATES Krebs cycle Krebs cycle Substrates required: 2 Oxaloacetic Acid Products: 2 Oxaloacetic Acid 2 Acetyl-CoA 6 NADH 6 NAD+ 2 FADH 2 2 FAD 2 GTP 2 GDP 4 CO 2 Intermediate Reactants: Citric Acid 6

9/14/16 OVERVIEW OF THE KREBS CYCLE OVERVIEW OF THE KREBS CYCLE ATP NETS: 3NADH, 1ATP , 1FADH 2 , & 2CO 2 KREBS CYCLE SUMMARY KREBS CYCLE SUMMARY Ø Requires Oxygen (Aerobic) Ø Each turn of the Krebs Cycle also Ø Cyclical series of oxidation reactions that give produces 3NADH, 1FADH 2 , and 2CO 2 off CO 2 and produce one ATP per cycle Ø Therefore, for each Glucose Ø Turns twice per glucose molecule molecule, the Krebs Cycle produces Ø Produces two ATP 6NADH, 2FADH 2 , 4CO 2 , and 2ATP Ø Takes place in matrix of mitochondria WHERE DOES CELLULAR RESPIRATION TAKE PLACE? REVIEW OF MITOCHONDRIA STRUCTURE It actually takes place l Smooth outer Membrane in two parts of the cell: l Folded inner membrane Glycolysis occurs in l Folds called Cristae the Cytoplasm l Space inside cristae called the Matrix Krebs Cycle & ETC take place in the Mitochondria 7

9/14/16 ATP PRODUCTION FROM CARBOHYDRAT AT ATES ATP PRODUCTION FROM CARBOHYDRAT AT ATES Electron Transport Chain A series of Oxidative Phosphorylation reactions Electron Transport Chain Oxidation = the removal of electrons from a molecule and results in a decrease in the Substrates required: 10 NADH energy content of the molecule. Because most 2 FADH 2 biological reactions involve the loss of hydrogen atoms, they are called 6 O 2 dehydrogenation reactions. Reduction = the opposite of oxidation; the Products: 32 ATP addition of electrons to a molecule, and results in an increase in the energy content of the 6 H 2 0 molecule. OVERVIE OV IEW OF ELECTRON TRANSPORT SYSTEM ELECTRON TRANSPORT CHAIN SUMMARY • 34 ATP produced • H 2 O produced • Occurs across Inner Mitochondrial membrane • Uses coenzymes NAD + and FAD + to accept e- from glucose • NADH = 3 ATP’s • FADH 2 = 2 ATP’s Overview of Cellular Respiration SUMMARY OF ATP PRODUCTION 8

9/14/16 LIPID METABOLISM PROTEIN METABOLISM Deamination: removal of the amino group (NH 2 ) • Lipoproteins: surrounding triglycerides with leaving a acetyl molecule apoproteins to make them more transportable in water Transamination: Adding an animo group to • Very low-density lipoproteins (VLDL ’ s) pyruvic acid to produce any of the • Low-density lipoproteins (LDL ’ s) nonessential amino acids • High-density lipoprteins (HDL ’ s) Protein Synthesis: Production of protein Lipolysis: break down lipids molecule using an RNA model. Beta Oxidation: breaking a fatty acid into 2 carbon compounds Protein catabolism: breaking down a protein Lipogenesis: formation of lipids from non-lipids into individual Amino Acids. OVERVIE OV IEW: SU SUMMARY OF THE INTERCONNECTION BETWEEN TI TISSUES AND ME METABOLISTIC RE REAC ACTI TIONS THE ROLE OF TH TH THE LIVER IN LIPID D METABO ABOLISM METABOLIC OVERVIEW: THE PO ME POSTABSORP RPTIVE ST STATE METABOLIC OVERVIEW: THE ABSORPTIVE STATE ME 9