2. •Energy is the capacity to do work or cause change
•Organisms store energy in organic molecules as chemical energy
•Free energy is the portion of energy released during chemical reactions
that is available to do work
Energy and Nutrients
3. Energy and Nutrients
Organisms obtain their energy through Autotrophy or Heterotrophy
Autotrophs are organisms capable of producing their own food
Heterotrophs are organisms that must obtain food from an outside source
by consuming another organism
5. The Law of Conservation of Energy (1st Law of Thermodynamics)
•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
6. 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)
7. Chemical Reactions Proceed as Follows:
Reactants Products
Energy must be added to “activate” the reaction and
break the bonds between atoms
Activation Energy
Metabolism and Energy Transfer
10. Energy Curve of an Uncatalyzed Exothermic
Reaction
Energy of
Reactants
Energy of
Products
Activation Energy
In cases like this (High
AE), reactions would occur
too slowly to support life!!!
11. 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!
Catalysts
12. Protein molecules that act
as catalysts
Specific to a Substance or
Reaction
Speeds up Biological
Reactions to
10,000,000,000 times
faster
Enzymes
13. Bind to Specific Reactants to Form a complex
Reactants enzymes interact with are called Substrates
Substrate binds to the enzyme at a location called the Active Site
How Enzymes Work
14.
15. E + S ES E + P
Catalase
Breaks H2O2 into H2O and O2
Hydrogen Peroxide is Toxic to Cells
Catalase + H2O2 Complex Catalase + H2O + O2
Enzymatic Reactions
17. Enzymes are named by taking either the name of the
substrate or the action performed and adding the ending “ase”
DNA Polymerase
Lactase
Ligase
Naming Enzymes
22. Decomposition reactions release free energy
Oxidation is the removal of electrons from a molecule
Bonds are broken and rearranged
Some energy of the original molecule is released as heat and free energy
Free energy is finally captured in ATP (adenosine triphosphate)
Energy Exchange in Cells
23. ATP
ATP is the cellular energy currency
Can store/release small amounts of energy
The bond between the 2nd and 3rd phosphate is made or
broken to exchange energy