CFLs – Unit 2
Chapter 8 – Introduction to Metabolism

1. Metabolism is the sum of an organism’s chemical reactions.

2. Catabolic pathways release energy by breaking down complex molecules into simpler compounds, while anabolic pathways consume energy to build complex molecules from simpler ones.

3. All laws of energy transformations are conserved. The first law of thermodynamics states that energy cannot be created or destroyed; it can only be converted from one form to another. The second law of thermodynamics is that all systems tend to increase in entropy.

4. Energy flows into an ecosystem in the form of light and exits in the form of heat.

5. The change in free energy (ΔG) determines if a reaction will occur spontaneously.

6. An exergonic reaction proceeds with a net release of free energy and is spontaneous (ΔG<0). An endergonic reaction absorbs free energy from its surroundings and is nonspontaneous (ΔG>0).

7. ATP (Adenosine Triphosphate) is the energy currency of the cell. ATP hydrolysis releases energy which is used to drive reactions forward.

8. Every reaction must overcome an activation energy barrier to occur. Enzymes speed up reactions by lowering the activation energy barrier.

9. The reactant that an enzyme acts on is called the enzymes substrate. The substrate binds to the enzyme in the enzyme’s active site to form the enzyme –substrate complex.

10. An enzymes environment can affect its activity. Factors such as temperature, pH and different chemicals can influence if an enzyme will work.

11. In competitive inhibition the inhibitor looks similar to the enzymes substrate and competes with the substrate for binding to the active site. In noncompetitive inhibition the inhibitor binds to an allosteric site causing a shape change making the active site less effective.