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Enzymes and Energy Transfer. There are three types of energy in the universe. Potential Energy (E P ) : Energy that is stored , either as energy of position, or chemical energy. Ex; Energy stored in a stretched rubber Band (position energy ) or in the food that
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Enzymes and Energy Transfer There are three types of energy in the universe. Potential Energy (EP) : Energy that is stored ,either as energy of position, or chemical energy Ex; Energy stored in a stretched rubber Band (position energy ) or in the food that you eat (chemical energy)
2) Activation Energy (EA): Energy required to begin a reaction Ex: Pushing a wagon to start it down a hill, the energy needed to start a chemical reaction. (Striking a match) 3) Kinetic Energy (EK) Energy of movement and heat Ex: A ball rolling down a hill (Movement) (Heat) A match burning
EK=EP-EA Kinetic Energy equals Potential Energy minus Activation Energy -Lowering EA to zero would make EK = EP (100% efficiency) -in other words, all the potential energy (100%)would be converted.
Enzymes Enzymes are complex molecules made of protein Enzymes work by lowering the activation energy (EA) of reactions
Enzymes are very specific for the molecules that they will work on. -Similar to a Lock and Key, only the correct key will fit the lock. The molecules that enzymes work on are called the substrate.
SUBSTRATE • Substrate (maltose) and enzyme come • together 2) Substrate fits exactly in the enzyme, and bond is over the active site of the enzyme 3) The enzyme puts a strain on the bond, breaking it. 2 smaller glucose molecules result.
Substrate 1 Substrate 2 Active Sites on Enzyme • Substrate molecules • are attracted to the active • sites on the enzyme Enzyme
Substrate 1 Substrate 2 2) Substrate molecules are firmly held by the enzyme at the active sites. Molecules are oriented so that bonding areas face together. Enzyme
Substrate 1 Substrate 2 3) Substrate molecules can now bond easily, because they are held in the proper orientation. Enzyme
New Substrate 2 New Substrate 1 Substrate 1 Substrate 2 4) Original substrate molecules are released, making room for two new molecules, and the process is repeated over and over. Enzyme
Coenzymes: -Molecules that help with the enzymatic reaction. (Make the reaction even more efficient) -Coenzymes are often vitamins or minerals
Types of Chemical Reactions • Exergonic (exothermic): Once • started, givesoff energy (heat) • Ex: Fire, “heat pack” Heat pack: Mg + H20 = Mg(OH)2 + H2 + heat
2) Endergonic (endothermic): Reaction uses energy, needs a constant input of energy (heat) Ex: Cold Pack -barium hydroxide and ammonium nitrate
Where does all that energy GO? The source of energy for most cellular endergonic reactions is ATP. ATP: Adenosine Triphosphate A P P P High Energy Bonds
High in potential energy A P P P P A P P Lower in potential energy Energy is given off ATP Becomes ADP, plus a free phosphate, plus free energy
The free energy is used to Power other reactions within the cell. Examples: Protein synthesis DNA synthesis
The source of energy to make ATP is cellular respiration. Cellular Respiration: “Burning” of sugar (glucose) to fuel cell reactions.
Aerobic vs. Anaerobic Respiration Aerobic: Takes place in the presence of oxygen C6H12O6 + 6O2 6CO2+6H2O Plus energy for 38 ATPs
Anaerobic: Takes place in the absence of oxygen C6H12O6 2CH3CHOHCOOH (Lactic Acid) Plus energy to create 4 ATPs
Fermentation: A form of anaerobic respiration that produces CO2 and alcohol from sugar C6H12O6 2C2H5OH + 2CO2 (Alcohol) Plus energy for 4 ATPs