AP Biology Chapter 6 Reading Guide: Energy & Metabolism 1 ...

AP Biology Chapter 6 Reading Guide: Energy & Metabolism
1. Define the following terms:
a. kinetic energy
b. potential energy
c. oxidation
d. reduction
2. Explain the First Law of Thermodynamics and its relationship to biological systems.
3. Explain the Second Law of Thermodynamics and its relationship to biological systems
4. What is meant by a change in free energy?
Free energy (aka Gibbs Free Energy, Gibbs Energy, or Gibbs Function) is the energy available for work.
For biology we are most concerned with the free energy stored in chemical bonds. A change in free
energy basically refers to a change in potential energy…it’s a little more complicated than that, but that’s
enough for us unless you care to investigate more online.
5. Compare reactions that are…
a. Exergonic
b. Endergonic
6. Sketch the profile of an exergonic reaction and sketch the profile of an endergonic reaction.
Use Figure 6-5 in your text to sketch the pictures of ender and exergonic reactions
7. Define activation energy.
8. How do enzymes affect the energy profile of a biological reaction?
“Energy profile” refers to the energy use and changes of when an enzyme is used…
9. Explain the induced fit model of enzyme action.
10. Why are enzymes said to be specific?
11. What are the advantages of multienzyme complexes?
Multienzyme complexes are groups of several enzymes that catalyze successive steps of a chemical
reaction…kinda like a packaged deal that you would purchase to get a discount on something…know what I
mean? They benefit a reaction by…
A. allowing the product of one step of the reaction to be efficiently transferred to the next step
without, say, getting lost or stolen…
B. eliminating the chance that the product may be involved with some side chemical reaction
C. controlling all reactions in one set as one unit
12. How has the discovery of catalytic RNA changed the our understanding of enzymes.
Catalytic RNA is cool. Catalytic RNA forms ribozymes, units that catalyze reactions involving RNA.
Ribozymes have some characteristics similar to enzymes—they are folded and shape specific. They are
used by RNA to remove unnecessary sequences of RNA from genes, prepare ribosomes for protein
synthesis, and prepare mitochondrial DNA for replication. It is thought that catalytic RNA is the
precursor for enzymes as we know them today—perhaps catalytic RNA evolved first and then catalyzed
the reactions that formed the enzymes we know, love, and have to have.

13. Explain how temperature and pH influence the rate of enzyme reactions.
a. temperature
b. pH
14. How do competitive and noncompetitive inhibitors differ in their enzyme interactions?
15. What happens during allosteric inhibition?
See “allosteric control” on page 106 of your textbook.
16. Explain the role of cofactors.
17. What is a coenzyme?
18. How does ATP “store energy”?
19. How does ATP “couple reactions”?
Be sure to read pages 98-99 carefully before approaching this question. It totally makes sense, but your
text doesn’t refer to “coupled reactions’ until the summary at the bottom of page 99.
20. Define the following metabolic terms
a. anabolism
b. catabolism
21. Explain how biochemical pathways could have evolved.
Early biochemical reactions took place with organic molecules scavenged from the environment. Generally,
reactions were simple, one-step events. But only organisms capable of synthesizing their own energy
could survive. Gradually energy use reactions were probably coupled with energy production reactions.
Photosynthesis is a great example of a process where energy production is coupled with energy use.
During the light dependent reactions, the plant synthesizes energy it needs to make food products.
During the light independent reactions, the ATP and other products are utilized to generate food
molecules from fixed CO 2 .
22. Describe feedback inhibition.