KIN 292 1st Edition Lecture 4 These are the notes from Professor Starnes lecture of Clinical Human Physiology These come from the slideshows provided by the professor and include extra notes and explanations Highlighted or bolded information are things that I believe to be information that is important to look over multiple times The notes in red are my personal additions and quotes of Professor Starnes from the class lecture Outline of Last Lecture I Biomolecules a Molecules synthesized by living things b Contain carbon 4 unpaired electrons II Four basic types a Carbohydrates b Lipids c Amino acids and proteins d Nucleotides Outline of Current Lecture I Types of Metabolic Reactions II Metabolic Reactions and Energy Current Lecture Types of Metabolic Reactions Metabolism the sum of all chemical reactions occurring in a cell Energy metabolism main focus of Ch 3 o Reactions involved in energy storage and use The basic principals chemical reactions apply to all machines including the human body o Bioenergetics the study of energy transfer in biological systems Metabolism chemical reactions in body o Anabolism Synthesis energy must be put onto the reactions o Catabolism Breakdown energy is given off when the reactions occur Coupled Reactions Some energy given off from catabolism is used for anabolic purposes These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Ex A portion of the energy released during glucose oxidation catabolism can be used to synthesize ATP o Example of catabolic reactions providing energy to be used for anabolic reactions o Take in energy from outside eating grass materials breakdown and excreted as water and nitrogenous waste Metabolism chemical reactions in body o Many physiological systems are involved in making sure that metabolism can occur in an individual cell of a given organ o Ex When a decrease in ATP concentration is detected in cell the cardiovascular system goes into action to increase the delivery of oxygen to that cell o ATP levels have to remain constant under all conditions Calorie and Joule are only units of measurement for energy o Energy expressed in calories cal or joules J 1 cal 4 18 J o Must have oxygen to go through the whole process how much heat energy is it producing using o 1 cal energy required to raise 1 mL by 1 C Heat is a form of energy that is released when substances are burned Oxygen is required for this o Calorimetry the measurement of energy change is briefly discussed in Ch 21 page 606 o Bomb calorimeter directly measures energy value of food o There is a known value of water and volume o Inside is a chamber that has oxygen and food that will be burned up Shows how much energy is needed to kill calories What is Energy The Capacity to do Work o Work Force x Distance kg m foot lb o 1 kcal 426 4 kg m or 3087 ft lb 100 efficient perfect machine where all energy is transferred directly to work does not exist Power F x D divided by Time W T watts Forms of Energy o Kinetic energy Associated with motion Thermal radiant electromagnetic electrical o Potential energy Stored energy Chemical mechanical nuclear gravitational Laws of Thermodynamics First Law of Thermodynamics Energy transfer Energy cannot be created or destroyed but is transformed from one form to another without being depleted o Conservation of energy Illustrated as body transforms energy in food to heat mechanical and chemical energy Heat will be given off Second Law of Thermodynamics Explains why energy is transferred All of the energy of the Universe will inevitable be degraded to heat and the organization of matter will become totally randomized Entropy randomness of a closed system will progressively increase and the amount of energy capable of performing work will diminish Nonrandom system entropy low contains energy by virtue of its orderliness in becoming disordered increase in entropy work can be performed The rhinoceros example from earlier is a closed system It is taking from the environment Second Law of Thermodynamics II The transfer of energy in any spontaneous process always proceeds in a direction that decreases the capacity to do work Work may or may not have been accomplished during the decrease in capacity for work it depends on whether the energy loss was connected to work recall the mechanical box Some of the mechanical energy from balls moving to one side was transferred to electrical energy The belt provided the coupling between the energy loss and energy gain Without belt only energy loss and none of it could be transferred The term free energy is used because this energy is available or free to do work As entropy increases free energy decreases Energy Changes in Reactions All reactions involve an exchange of energy Molecules possess energy Reactants possess more energy than products o reactants products energy Change in energy of a reaction E o E Ereactants Eproducts Putting previous 2 E pictures together Going from C to D can only occur if the reaction is coupled to A to B and E1 is greater than E2 2nd Law thing C D example synthesis of ATP A B example a step reaction in the catabolism breakdown of glucose that yields ATP as a product Activation Energy Transition state o Reactant and product transformations are not sudden Activation energy barrier Energy of barrier activation energy Limits how fast a reaction goes Level of required activation energy is reached then reaction will spontaneously occur to completion 2nd Law Level of required activation energy not reached no reaction happens Bomb calorimeter When temperature gets hot activation energy barrier is overcome and all the burns to completion enough substance Role of Enzymes in Chemical Reactions Enzymes o Proteins that are catalysts for reactions in biological systems o Catalysts increase the rates of chemical reactions Enzymes function by decreasing the activation energy for a specific chemical reaction Enzymes bind to a reactant substrate enzyme substrate ES product enzyme