LECTURE: INTRODUCTION TO METABOLISM
LECTURE: INTRODUCTION TO METABOLISM KIRSTIN BROWN
Lecture: INTRODUCTION TO METABOLISM Outline: 1. Thermodynamics o Kinetic and potential energy o Gibb’s free energy o Enthalpy and entropy 2. Exergonic and Endergonic Reactions
Metabolism The sum of all chemical reactions in an organism o Our cells are constantly carrying out
thousands of reactions
o Some reactions produce energy, and others
require energy
Metabolism The sum of all chemical reactions in an organism o Our cells are constantly carrying out
thousands of reactions
o Some reactions produce energy, and others
require energy
Food molecules CATABOLISM
Cell components ADP
ANABOLISM
ATP
CO2, Waste
Building blocks
Thermodynamics Biological thermodynamics is a quantitative study of energy transduction in and between cells. o Defined by the Gibb’s Free Energy Function
∆G = ∆H - T ∆S o Can be used to determine if a reaction will
occur spontaneously
Thermodynamics Energy Transduction o The change in one form of energy to another o Energy can be stored as: ➢ Potential energy ➢ Kinetic energy
Potential Energy
energy in
Kinetic Energy
energy out
Kinetic Energy
Thermodynamics Energy Transduction o The change in one form of energy to another o Energy can be stored as: ➢ Potential energy ➢ Kinetic energy
Potential Energy
Kinetic Energy
Thermodynamics Fundamental laws of thermodynamics o First Law: For every chemical change, the
total amount of energy in the universe remains constant ➢ energy may change from one form to another, but it can neither by created or destroyed.
o Second Law: In all natural processes, the
entropy of the universe increases. Therefore, in spontaneous reactions energy is dispersed.
Thermodynamics
∆G = ∆H - T ∆S
Enthalpy, H o The heat content of a system o Measured in Joules (J/mol)
o Sum of kinetic energy and potential energy ➢ Exothermic: Heat content of the product is
less than the reactants (heat is released)
➢ Endothermic: Heat content of the product is
more than the reactants (heat is required)
Exothermic
Example: Glucose + ATP glucose-6-Pi + ADP ΔH = -35 kJ/mol
Endothermic
Example: Glucose-6-Pi fructose-6-Pi ΔH = +12 kJ/mol
Thermodynamics
∆G = ∆H - T ∆S
Entropy, S o A quantitative expression of randomness or disorder of a system and its surroundings o Measured in Joules/Kelvin (J/mol K)
Thermodynamics
∆G = ∆H - T ∆S
Gibb’s free energy, G o Amount of energy capable of doing work o Measured in Joules/mol (J/mol)
Standard free energy change, ∆G° o Change in free energy under standard conditions ➢ 298 K, 1 atm, 1 M concentration of all
reactants
Thermodynamics
∆G = ∆H - T ∆S
Gibb’s free energy, G o Amount of energy capable of doing work o Measured in Joules/mol (J/mol) o Spontaneous reactions have an overall
negative ∆G
Exergonic
Note: spontaneous ≠ Fast Endergonic
Summary ∆G = ∆H - T ∆S o H = enthalpy or total energy (J/mol) o G = free energy to do work (J/mol) o S = entropy or unusable energy (J/mol K) o T = temperature (K)
Summary A reaction has a ΔH of +12 kJ/mol, a ΔSsurroundings of 30.2 J/mol K, and a ΔSsysem of -40.7 J/mol K. Calculate the change in free energy and determine if the reaction is spontaneous, 298 K.
Summary A reaction has Gibb’s free energy change of -30 kJ/mol at 293 K and a ∆S of +70 J/mol K. Is the reaction endothermic or exothermic?
Lecture: INTRODUCTION TO METABOLISM Outline: 1. Thermodynamics o Kinetic and potential energy o Gibb’s free energy o Enthalpy and entropy 2. Exergonic and Endergonic Reactions
Metabolism The sum of all chemical reactions in an organism o Our cells are constantly carrying out
thousands of reactions
o Some reactions produce energy, and others
require energy
Metabolism The sum of all chemical reactions in an organism o Our cells are constantly carrying out
thousands of reactions
o Some reactions produce energy, and others
require energy
Food molecules CATABOLISM
Cell components ADP
ANABOLISM
ATP
CO2, Waste
Building blocks
Thermodynamics Biological thermodynamics is a quantitative study of energy transduction in and between cells. o Defined by the Gibb’s Free Energy Function
∆G = ∆H - T ∆S o Can be used to determine if a reaction will
occur spontaneously
Thermodynamics Energy Transduction o The change in one form of energy to another o Energy can be stored as: ➢ Potential energy ➢ Kinetic energy
Potential Energy
energy in
Kinetic Energy
energy out
Kinetic Energy
Thermodynamics Energy Transduction o The change in one form of energy to another o Energy can be stored as: ➢ Potential energy ➢ Kinetic energy
Potential Energy
Kinetic Energy
Thermodynamics Fundamental laws of thermodynamics o First Law: For every chemical change, the
total amount of energy in the universe remains constant ➢ energy may change from one form to another, but it can neither by created or destroyed.
o Second Law: In all natural processes, the
entropy of the universe increases. Therefore, in spontaneous reactions energy is dispersed.
Thermodynamics
∆G = ∆H - T ∆S
Enthalpy, H o The heat content of a system o Measured in Joules (J/mol)
o Sum of kinetic energy and potential energy ➢ Exothermic: Heat content of the product is
less than the reactants (heat is released)
➢ Endothermic: Heat content of the product is
more than the reactants (heat is required)
Exothermic
Example: Glucose + ATP glucose-6-Pi + ADP ΔH = -35 kJ/mol
Endothermic
Example: Glucose-6-Pi fructose-6-Pi ΔH = +12 kJ/mol
Thermodynamics
∆G = ∆H - T ∆S
Entropy, S o A quantitative expression of randomness or disorder of a system and its surroundings o Measured in Joules/Kelvin (J/mol K)
Thermodynamics
∆G = ∆H - T ∆S
Gibb’s free energy, G o Amount of energy capable of doing work o Measured in Joules/mol (J/mol)
Standard free energy change, ∆G° o Change in free energy under standard conditions ➢ 298 K, 1 atm, 1 M concentration of all
reactants
Thermodynamics
∆G = ∆H - T ∆S
Gibb’s free energy, G o Amount of energy capable of doing work o Measured in Joules/mol (J/mol) o Spontaneous reactions have an overall
negative ∆G
Exergonic
Note: spontaneous ≠ Fast Endergonic
Summary ∆G = ∆H - T ∆S o H = enthalpy or total energy (J/mol) o G = free energy to do work (J/mol) o S = entropy or unusable energy (J/mol K) o T = temperature (K)
Summary A reaction has a ΔH of +12 kJ/mol, a ΔSsurroundings of 30.2 J/mol K, and a ΔSsysem of -40.7 J/mol K. Calculate the change in free energy and determine if the reaction is spontaneous, 298 K.
Summary A reaction has Gibb’s free energy change of -30 kJ/mol at 293 K and a ∆S of +70 J/mol K. Is the reaction endothermic or exothermic?
