1. All living things require energy
Intro to Metabolism

2. The Energy of Life
The living cell is a miniature chemical factory where thousands of reactions occur
The cell extracts energy and applies energy to perform work

3. Metabolism is the totality of an organism’s chemical reactions
Reactions generally fall into 2 categories
Making reactions-require energy
Breaking reactions-release energy

4. Chemical Reaction
When one or more substance are converted into different substances with different properties
Reactants – substances that undergo a chemical reaction
Products – substances that are produced by the reaction

5. Types of Pathways
Catabolic pathways release energy by breaking down complex molecules into simpler compounds
Cellular respiration is an example
Anabolic pathways consume energy to build complex molecules from simpler ones
Photosynthesis is an example
Bioenergetics is the study of how organisms manage their energy resources

6. Chemical Reactions Either Require or Release energy
Energy is the capacity to cause change or do work
An exergonic reaction proceeds with a net release of energy and is spontaneous (breaking)
An endergonic reaction absorbs energy from its surroundings and is nonspontaneous (making)

7. Laws of Thermodynamics
During every energy transfer or transformation, energy is conserved
However, some energy is unusable, and is often lost as heat
Reactions tend to lose ordered forms of energy

8. Activation Energy (Ea) Barrier
Progress of the reaction
Products
Reactants
∆G < O
Transition state
Free energy EA D C B A

9. Reaction Rate Speed of a chemical reaction
The rate of a reaction is determined by how much energy it takes to reach the transition state

10. Enzymes
Catalysts are chemicals that speed up reactions by lowering the activation energy
Enzymes are a kind of protein that act as catalysts in biological reactions
Each enzyme has an optimal temperature and pH in which it can function

11. Most Biological reactions occur in many ordered steps
A metabolic pathway begins with a specific molecule and ends with a product
Each step is catalyzed by a specific enzyme