1. State the first and second laws of thermodynamics in your own words.
2. What are some things that cells need energy for?
3. We often say that glucose and fat molecules are "energy rich." What does that really mean? Where is that energy?
4. What is heat?
5. How are entropy and heat related?
6. If the reactants contain more free energy than the products in a reaction, is this reaction endergonic or exergonic? What if the reactants contain less free energy than the products? In which case is DG negative?
7. What does it mean to say that endergonic and exergonic reactions are "coupled?"
8. What does ATP stand for? Draw a cartoon diagram of ATP.
9. Why do cells use ATP to hold energy rather than just directly use the energy available from the breaking of glucose bonds?
ENZYMES
1. What does it mean for a reaction to be spontaneous? Are all spontaneous reactions fast?
2. What controls the rate of a reaction?
3. What is activation energy? How is it defined? Why must energy be added to a reaction?
4. Do endergonic reactions have activation energy?
5. Consider the following reaction diagrams. On each diagram, show DG and the activation energy. Then show how the reaction might proceed if an enzyme were added.
6. How does heat increase the rate of a reaction? What is a catalyst?
7. To what macromolecule group do enzymes belong? What controls the ability of an enzyme to function?
8. What is an active site? How does an enzyme lower activation energy? What goes on in the enzyme-substrate complex?
9. Why are enzymes specific? How does the cell take advantage of the specificity of enzymes to "multi-task?"
10. How do acids and bases denature an enzyme? How does a high salt concentration denature an enzyme?
11. How does heat denature an enzyme?
12. In your own words, define or describe a metabolic pathway (e.g., A -> B -> C -> D). Which letters represent reactants or substrates and which represent products? What does the arrow represent? How many enzymes (minimally) area involved in the pathway shown?
13. What is an allosteric enzyme? How is the word "allosteric" litterally translated? How is an allosteric enzyme regulated? What is an effector?
14. What is feedback inhibition? How can feedback inhibition maintain a relatively constant concentration of a product?
15. In the following hypothetical pathway, the end product Z inhibits the catalysis of W to X. However, the conversions of X->Y and Y->X are unregulated. Why would it be most useful for Z to act where it does?
16. In the following branched metabolic pathways, an arc with a minus sign symbolizes inhibition of a metabolic step by an end product.
a. Given the above pathway, which reaction would predominate if there is a high concentration of E in the cell?
b. Given the above pathways, which reaction would predominate if there are high concentrations of both Q and S in the cell?