Metabolism – Chapters 8, 9, and 10
Metabolism refers to the set of chemical reactions that occur in an organism. These reactions can be
anabolic or catabolic in nature. Photosynthesis and cellular respiration are examples. Enzymes
facilitate many metabolic reactions.
Learning Goals


Describe the chemical processes involved in cellular respiration.
Describe the chemical processes involved in photosynthesis.
Vocabulary
Metabolic pathway
Anabolic pathway
Catabolic pathway
Kinetic energy
Potential energy
Chemical energy
First law of
thermodynamics
Second law of
thermodynamics
Spontaneous
process
Entropy
Enthalpy
Free energy
ΔG=ΔH-TΔS
Exergonic reaction
Endergonic reaction
Energy coupling
Phosphorylated
intermediate
Activation energy
Substrate
Enzyme
Active site
Induced fit
Cofactor
Coenzyme
Noncompetitive
inhibitor
Allosteric regulation
Feedback inhibition
Mitochondria
NAD+
NADH
FADH
FADH2
CO2
H2O
O2
Inner mitochondrial
membrane
ATP
asdf
ADP
Pi
Aerobic
Oxidize
Reduce
Glucose
Glycolysis
Pyruvate oxidation
Citric acid cycle
Krebs Cycle
Oxidative phosphorylation
Substrate level
phosphorylation
Cytosol
Electron transport chain
Free energy
Acetyl CoA
ATP synthase
Chemiosmosis
Proton motive force
Chemical energy
Potential energy
-686 kcal/mol
7.3 kcal/mol
34%
autotroph
mesophyll
stomata
stroma
thylakoids
chlorophyll
light reactions
Calvin cycle
NADP+
NADPH
Photophosphorylation
Carbon fixation
Photons
Spectrophotometer
Absorption spectrum
Carotenoid
Analysis Questions
1. What are the three main types of work
carried out by cells?
2. How do changes in free energy differ in
exergonic and endergonic reactions?
3. What are redox reactions? Provide an
example and label the oxidizing and reducing
agents in your chemical equation.
4. In terms of free energy (∆G), explain why
cellular respiration is an exergonic process.
5. Cellular respiration is said to be 40% energy
efficient. Justify this claim using energy
measurements (kcal/mol). Also, where does
the rest of the energy go?
6. Using the terms potential energy and
electronegativity, explain why macromolecules
are an excellent source of energy in aerobic
environments.
7. Why are macromolecules not spontaneously
degraded in cells?
8. How is oxygen’s role in cellular respiration
similar to NAD+ and FAD? How is it different?
9. How is oxidative phosphorylation different
from substrate-level phosphorylation?
10. Why is glycolysis not really considered part
of cellular respiration?
11. Why are some of the intermediates of
glycolysis phosphorylized?
12. Identify the roles of acetyl CoA, CO2, H2O,
NAD+, FAD, GDP, and oxaloacetate in the Krebs
cycle.
Photosystem II
Photosystem I
Linear electron flow
Cyclic electron flow
G3P
RuBP
Photorespiration
C3
C4
Bundle sheath cells
PEP carboxylase
CAM
13. Describe how the proton-motive force
drives ATP synthesis.
14. Explain how the role of pyruvate changes in
aerobic and anaerobic conditions.
15. Are proteins and lipids used as fuel for
cellular respiration in the same way as
carbohydrates? Explain.
16. How is phosphofructokinase used to
regulate ATP synthesis rates in cells?
17. Are the molecules involved in glycolysis
and the Krebs cycle used only for catabolism?
Explain.
18. What are the light and dark reactions?
19. What is the difference between C3, C4, and
CAM?
20. What are absorption spectra and action
spectra?
21. What are the differences between
photosystem I and II?
22. What is the difference between cyclic and
noncyclic electron flow?
23. What is the difference between cyclic and
noncyclic photophosphorylation?
24. Describe chemiosmosis in chloroplasts. Is it
the same as in mitochondria?
25. Why are carotenoids important to plants?
26. What is the role of RuBP in photosynthesis?
G3P?
27. Describe the relationship between
photosynthesis and cellular respiration.