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Energy cannot be created or destroyed, but it can change form
The total energy of the universe is constant
Organisms cannot create their own energy but must obtain it from an outside source
The Second Law of Thermodynamics
There is a natural tendency towards disorder “entropy”
Energy is required to resist entropy
An organism must be well organized to remain alive and grow (Organization requires energy)
Chemical Reactions Proceed as Follows: Reactants Products Metabolism and Energy Transfer Energy must be added to “ activate ” the reaction and break the bonds between atoms
Under Normal Conditions, a High Amount of Energy is Needed to Start a Reaction Activation Energy In cases like this ( High AE ), reactions would occur too slowly to support life!!! Energy of Reactants Energy of Products
Catalysts Catalysts speed up the rate of a reaction by lowering the activation energy needed to get the reaction going Catalysts are not changed or used up during a reaction!
A Catalyzed Reaction… Requires less energy to get started!!! Energy of Reactants Energy of Products Activation Energy
The Living Cell has Special Molecules Which Act as Catalysts……. Enzymes
Specific to a Substance or Reaction
Speeds up Biological Reactions to 10,000,000,000 Times Faster
How do Enzymes Work? Bind to Specific Reactants to Form a Complex Reactants called Substrates Substrate Binds to the Enzyme at the Active Site
Enzymatic Reactions Important Enzyme: Catalase Breaks H 2 O 2 into H 2 O and O 2 Hydrogen Peroxide is Toxic to Cells Enzymes use “induced fit” to help bonds form or break between compounds E + S ES E + P Catalase + H 2 O 2 Complex Catalase + H 2 O + O 2
Naming Enzymes Enzymes are named by taking either the name of the substrate or the action performed and adding the ending “ ase ”
***Temperatures too high or low will denature the enzyme!
Chemical Reactions in Organisms Metabolism : All the chemical activities in a cell or organism Synthesis: “building-up” reactions biosynthesis, photosynthesis dehydration synthesis Decomposition: “breaking down” reactions cellular respiration, digestion hydrolysis