Overview of Metabolism PDF

OVERVIEW OF METABOLISM Lesson 6 Overview of metabolism • Biological transformations of energy. • Anabolic and catabolic reactions. • Energy-rich compounds: ATP. • Endergonic and exergonic reactions, coupled reactions. Metabolism Metabolism: The entire set of enzyme-catalyzed transformatio...

OVERVIEW OF METABOLISM Lesson 6 Overview of metabolism • Biological transformations of energy. • Anabolic and catabolic reactions. • Energy-rich compounds: ATP. • Endergonic and exergonic reactions, coupled reactions. Metabolism Metabolism: The entire set of enzyme-catalyzed transformations of organic molecules in living cells • Living cells and organisms must perform work to stay alive, to grow, and to reproduce • Organisms carry out a remarkable variety of energy transductions conversions of one form of energy to another • They use the chemical energy in fuels (food):  Synthesis of complex, highly ordered macromolecules from simple precursors  Concentration gradients and electrical gradients  Motion and heat Metabolism BASIC PRINCIPLES GOVERN ENERGY MANIPULATIONS IN ALL CELLS • Molecules are degraded or synthesized in a series of reactions termed metabolic pathways. In some of these pathways, energy is released and in others, energy is required. • ATP is the energy currency of life and can be given to the pathways that need energy or can be produced by the ones that release energy. • ATP can be formed by the oxidation of carbon (oxidation compounds like glucose and fatty acids…) • Metabolic pathways are highly regulated by the regulatory enzymes. Metabolism • Anabolism: The phase of intermediary metabolism concerned with the energy-requiring biosynthesis of cell components from smaller precursors, typically a reductive process. • Catabolism: The phase of intermediary metabolism concerned with the energy-yielding degradation of nutrient molecules, typically an oxidative process. Metabolism Adenosine triphosphate (ATP) • ATP is the energy currency of cells • Links catabolism and anabolism Structure Adenosine Adenine (nitrogenous base) + Ribose (Carbohydrate) 3 phosphate groups Phosphate exhibits negative charges the phosphates tend to repel between them and this makes the molecule unstable. This is why it can be spontaneously hydrolyzed and when this occurs energy is released Adenosine triphosphate (ATP) ATP-ADP CYCLE • ATP cycle carries energy from catabolism to the energyrequiring of cells processes . • When we eat, the nutrients that are absorbed in our organism are oxidized by the catabolic pathways and ATP is produced. • When we do exercise ATP is needed for the muscle contraction, and ATP is converted into ADP +Pi. • These two components can bind again using the energy coming from the catabolism of nutrients Energy-rich compounds • ATP is not the only energyrich compound (compounds that can be spontaneously hydrolyzed, and when hydrolyzed they release energy) that we have. • The ATP releases a small amount of energy, so it can be resynthesized when another energy-rich compound (that releases more energy than ATP) is hydrolyzed. PEP; 1,3-BPG and creatinine phosphate How ATP is synthesized? Oxidative phosphorylation Substrate-level phosphorylation • Metabolism reaction that results in the production of ATP supported by the energy released from another high-energy bond that leads to phosphorylation of ADP to ATP • Quicker, less efficient source of ATP • Occurs in the absence of mitochondria or anaerobiosis  oxygen is not required • Not frequent • Catalized by ATP Synthase  Mitochondria • Oxigen required  Aerobiosis • Free phosphate is bonded to ADP  the energy required is obtained in the electron transport chain • The most frequent source of ATP Catabolism overview • Oxidative process  substrates lose electrons • Oxidize coenzymes (NAD+ and FAD2+) collect the electrons and reduce (NADH and FADH2)  Electrons are transfer to the electron transport chain to allow the formation of ATP Catabolism: The phase of intermediary metabolism concerned with the energy-yielding degradation of nutrient molecules, typically an oxidative process. Oxidation: The loss of electrons from a compound. Oxidation-reduction (Redox) reactions and coenzymes Oxidation: The loss of electrons from a compound. Reduction: The gain of electrons by a compound 2 Redox pair: An electron donor and its corresponding oxidized form; for example, NADH and NAD+. Anabolism Reductive process REDOX COENZYMES Catabolisms Oxidative process Redox reaction: A reaction in which electrons are transferred from a donor to an acceptor molecule