The Flow of Energy Within Organisms
Mighty Mini Motor In The News
Energy and Life Life involves a constant flow of energy Energy = ability to do work Energy states Potential Kinetic
Potential Energy Potential Energy Kinetic Energy Energy not actively doing work Kinetic Energy Energy of motion
Energy Laws Laws of Thermodynamics First law Energy can neither be created or destroyed Second law Disorder in a closed system tend to increase
Entropy Measure of disorder Energy is required to overcome entropy Organisms have an input of energy to continue to function
Energy and Chemical Reactions Chemical reactions release & store energy
Activation Energy Required to start reactions Helps break or destabilize bonds
Exergonic Reaction Energy is released Proceed spontaneously once started Catabolic reactions Breaks complex molecules to simple Releases energy Common in organisms
Endergonic reaction Energy used in bonding reactants Builds molecules Called anabolic reactions
Metabolic Pathways Move, store, & release energy Keep bodies working
Enzymes Lower activation energy Increase rate of reaction (catalyst)
Substrates Substances on which enzymes work Bound to active sites by enzymes
How Enzymes Catalyze an Exergonic Reaction
Enzyme Substrate
Enzymes can Catalyze Reactions Between Two Substrates
Environmental Conditions Affect Enzyme Activity Temperature Can change enzyme shape Can affect enzyme activity
Enzymes Work Best in Conditions Specific to an Organism
Other Factors Affecting Enzymes pH Presence of chemicals binding to enzymes Activators catalyze reactions Inhibitors shuts off enzyme activity
End Products Can regulate enzyme activity
Cofactors Additional parts of enzymes Molecules other than proteins Help catalyze chemical reactions
Coenzymes Organic cofactor Synthesized with vitamins Important for many functions
ATP Adenosine triphosphate Primary energy carrier of living systems
ATP Unstable covalent bonds on phosphate Requires little activation energy High energy transfer potential
Phosphorylation Energy transferred along with phosphate Used for most cellular work
ATP – ADP Cycle ATP loses phosphate group Phosphate is added to ADP Energy is released Hydrolysis Product is ADP (adenosine diphosphate) Phosphate is added to ADP Requires energy from exergonic reactions Dehydration synthesis Product is ATP
End Chapter 6