AP Biology
Name: ____________________________________________
Chapter 8 Reading Guide
Metabolism – page 141
Counts as test grade on 3rd quarter grade!
8.1: An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics
1. Define metabolism. ___________________________________________________________________
2. There are two types of reactions in metabolic pathways: anabolic and catabolic.
CIRCLE OR HIGHLIGHT.
a. Which reactions release energy? anabolic or catabolic
b. Which reactions consume energy? anabolic or catabolic
c. Which reactions build up larger molecules? anabolic or catabolic
d. Which reactions break down molecules? anabolic or catabolic
e. Which reactions are considered “uphill”? anabolic or catabolic
f. What type of reaction is photosynthesis? anabolic or catabolic
g. What type of reaction is cellular respiration? anabolic or catabolic
h. Which reactions require enzymes to catalyze reactions? anabolic or catabolic
3. What is energy? _______________________________________________________________
4. Contrast kinetic energy with potential energy.
5.
a. Which type of energy does water behind a dam have? _________________________
b. A mole of glucose? _________________________
c. The transfer of heat from one object to another? _________________________
6. Thermodynamics = ______________________________________________________________
a. What does each law state?
First law of thermodynamics:
Second law of thermodynamics:
b. How does the second law of thermodynamics help explain the diffusion of a substance
across a membrane?
8.2: The free-energy change of a reaction tells us whether the reaction occurs spontaneously
7. What is Gibb’s free energy? What is its symbol and equation?
8. Other symbols in the equation
∆H = __________________________________________
T = __________________________________________ (K = ˚C + _________)
∆S = __________________________________________
9. Free Energy and Metabolism
A negative ∆G means ∆G < 0 and that the process is _________________________________
and will occur without the input of energy.
A positive ∆G means ∆G > or = 0 and that the process is _____________________________
and absorbs energy.
For an exergonic reaction, is ∆G negative or positive? _________________
Exergonic means “energy outward” and endergonic means “energy inward.”
Do they release or absorb energy? _________________________________
For an endergonic reaction, is ∆G negative or positive? _________________
Exergonic means “energy outward” and endergonic means “energy inward.”
Do they release or absorb energy? _________________________________
10. For a reaction to be spontaneous; there must be a decrease in free energy (-G), the system must lose
energy (decrease H) and become more disordered (increase in S)
11. Is cellular respiration an endergonic or an exergonic reaction? What is ∆G for this reaction?
12. Is photosynthesis endergonic or exergonic? What is the energy source that drives it?
13. To summarize, if energy is released, ∆G must be what? ______________________________
8.3: ATP powers cellular work by coupling exergonic reactions to endergonic reactions
14. List the three main kinds of work that a cell does. Give an example of each.
(1)
(2)
(3)
15. Here is a molecule of ATP. Label it. Use an arrow to show which bond is likely to break.
By what process will that bond break?
Explain the name ATP by listing all the
molecules that make it up.
15. When the terminal phosphate bond is
broken, a molecule of inorganic phosphate
Pi is formed, and energy is absorbed or
released?
16. For this reaction: ATP + H2O
ADP + Pi, ∆G = __________________________
Is this reaction endergonic or exergonic?
17. What are the molecules that make up ATP?
18. What is energy coupling? ______________________________________________________________
19. In many cellular reactions, a phosphate group is transferred from ATP to some other molecule in
order to make the second molecule less stable. The second molecule is said to be…
20. How does ATP regenerate itself?
8.4: Enzymes speed up metabolic reactions by lowering energy barriers
21. What is a catalyst?
22. What is activation energy (EA)?
23. On the graph, label the x-axis “Progress of the reaction” and the y-axis “Free Energy.”
Label EA on this sketch, both with and without enzyme.
a. What effect does an enzyme have on EA? ______________________________________
b. Label ∆G. Is it positive or negative?
c. How is ∆G affected by the enzyme?
24. Label this figure while you define each of the
following terms:
enzyme
substrate
active site
products
25. What is meant by induced fit? How is it shown in this figure?
26. Explain how protein structure is involved in enzyme specificity.
27. Enzymes use a variety of mechanisms to lower activation energy. Describe four of these
mechanisms.
(1)
(2)
(3)
(4)
28. Many factors can affect the rate of enzyme action. Explain each factor listed here.
a. initial concentration of substrate
b. pH
c. temperature
29. Recall that enzymes are globular proteins. Why can extremes of pH or very high temperatures
affect enzyme activity?
30. Distinguish between cofactors and coenzymes. Give examples of each.
31. Compare and contrast competitive inhibitors and noncompetitive inhibitors. Label each type of
inhibitor in the figure on .