CHAPTER 6
All living things require a constant supply of energy
Energy is derived from the sun
Sugars possess energy because they contain “high energy electrons”
Like a roller coaster on top of a hill
ATP Adenosine TriPhosphate
Comes from energy released from chemical reactions
ATP can release energy when needed
ADP Adenosine DiPhosphate
1st Law of Thermodynamics
Energy cannot be created or destroyed
Energy can be transformed
Energy can be converted
Example: Chemical bond energy heat energymechanical energy
2nd Law of Thermodynamics
Energy transfer always results in a greater amount of disorder (“entropy”) in the universe
Energy transformations will run spontaneously in one direction only
With energy transformation, a portion of the energy is converted to heat
Biological systems are relatively efficient at energy conversion
ATP and ADP can be inter-converted
ADP + P = ATP requires energy
ATP = ADP + P releases energy
Enzymes are protein catalysts
The production of enzymes is encoded by units of DNA called genes
For any chemical reaction to occur, an initial input of energy is required
Enzymes function by reducing the required energy input
Enzymes only accelerate reactions that would occur anyway
Many activities are multi stepped.
Series of reactions called a metabolic pathway
Metabolic pathway set of enzymatically controlled steps resulting in the completion of
a product or process
Each enzyme performs a specific task
Substrate Product
