1. Chapter 3.1 McGraw-Hill Ryerson Biology 12 (2011)
Metabolism and Energy
Chapter 3.1
McGraw-Hill Ryerson
Biology 12 (2011)

2. Metabolism
Metabolism: sum of all chemical reactions that occur in the cell
Metabolic pathway: sequential series of chemical reactions in living cells; each reaction is catalyzed by an enzyme

3. Metabolism 2 ways to work with molecules:
Catabolism: process of breaking down compounds into smaller molecules to release energy
Anabolism: process of using energy to build large molecules from smaller molecules

4. Energy Kinetic Energy: energy of motion
Potential Energy: stored energy
Bond Energy: energy required to break or form a chemical bond

5. Thermodynamics
Thermodynamics is the study of transfer and transformation of thermal energy (heat)
Applies to a system and its surroundings System: whatever object(s) are being studied in an environment
Can be open or closed
Open means that system and surroundings exchange matter with each other (uncontained)
Closed means that the system can only exchange matter and materials within itself (contained)

6. Thermodynamics
Thermodynamics is the study of transfer and transformation of thermal energy (heat)
1st Law: Energy cannot be created or destroyed, but it can be transformed from one type into another and transferred from one object to another
2nd Law: During any process, the universe tends toward disorder
Entropy: measure of disorder

7. Thermodynamics
Free energy: energy from a chemical reaction that is available for doing work
Both chemical bonding and heat have a significant influence on a molecule (chemical bonding reduces disorder; heat increases it)
The net amount of energy actually available to break and form other bonds is free energy

8. Thermodynamics Gibbs Free energy:
All chemical systems tend naturally toward states of minimum Gibbs free energy
Where:
ΔG = Change in Gibbs Free Energy
Δ H = Change in Enthalpy (heat content)
T = Temperature in Kelvins
Δ S = Entropy (can think of as randomness)

9. Thermodynamics
Endergonic: chemical reaction that requires energy (ΔG is positive)
Exergonic: chemical reaction that releases energy (ΔG is negative)

10. Thermodynamics
Hydrolysis of ATP to ADP is highly exergonic

11. Coupled Reactions Cells use ATP to drive endergonic reactions
Hydrolysis of ATP releases energy but if uncoupled will merely be lost as heat
Thus ATP is coupled to fuel other reactions in the cell

12. Electron Carriers Redox reactions are coupled reaction
Influence flow of energy in biological systems
Electrons that pass from one atom to another carry energy, reducing power
Reduced form of a molecule is always at a higher energy level than oxidized form
Electron Carriers: compounds that pick up electrons from energy-rich compounds and donate them to low-energy compounds

13. Homework
Pg. 121 #2, 4, 5, 8