Bio 2
Fall, 2010
Updated 10/7/10
Study Guide
For Exam 2
Exam 2 will cover Chapter
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Be sure to read all chapters and take the time to be sure that you understand the
material.
Hopefully, you are keeping up with Mastering Biology! All of those materials are
available for you to review after the due date. This is a very good way to study for
the exam.
This study guide is intended to help you focus your work, but be sure to accomplish
the steps listed above first.
Chapter 7:
Membrane Structure
1. Explain the meaning of the statement that phospholipids and most other
membrane constituents are amphipathic molecules.
2. Explain how the fluid mosaic model of membrane structure explains each
experimental finding:
a. Membranes with different functions may differ in type and number of
membrane proteins.
b. Membrane proteins are not very water-soluble.
c. EMs of freeze-fracture membrane preparations show protein particles
interspersed in a smooth matrix.
3. Describe the fluidity of the components of a cell membrane and explain how
membrane fluidity is influenced by temperature and membrane composition.
4. Explain how cholesterol resists changes in membrane fluidity as temperatures
change.
5. Distinguish between peripheral and integral membrane proteins.
6. List six major functions of membrane proteins.
7. Explain the role of membrane carbohydrates in cell-cell recognition.
Transport across Membranes
8. Explain how hydrophobic molecules cross cell membranes.
9. Distinguish between channel proteins and carrier proteins.
10. Explain how aquaporins facilitate the passage of water through membranes.
11. Define diffusion. Explain why diffusion is a passive and spontaneous process.
12. Explain why a concentration gradient of a substance across a membrane
represents potential energy.
13. Distinguish between solutions that are hypertonic, hypotonic, and isotonic to cell
contents.
14. Define osmosis and predict the direction of water movement based on differences
in solute concentrations.
15. Explain how transport proteins facilitate diffusion.
16. Distinguish between osmosis, facilitated diffusion, and active transport.
17. Describe the two forces that combine to produce an electrochemical gradient.
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Bio 2
Fall, 2010
Updated 10/7/10
18. Explain how an electrogenic pumps creates voltage across a membrane while also
building a concentration gradient for ions. Name two electrogenic pumps.
19. Describe the differences between primary active transport, secondary active
transport, and passive transport
20. Describe the process of cotransport and be able to identify the source of the
energy to drive cotransport (e.g. Na+ gradient in animal cells).
21. Explain how large molecules are transported across a cell membrane.
22. Distinguish between exocytosis and receptor-mediated endocytosis.
CHAPTER 8: AN INTRODUCTION TO METABOLISM
Metabolism, Energy, and Life
1. Explain the role of catabolic and anabolic pathways in cellular metabolism.
2. Distinguish between kinetic and potential energy.
3. Distinguish between an isolated and an open system. Explain why an organism is
considered an open system.
4. Explain the first and second laws of thermodynamics in your own words.
5. Explain why highly ordered living organisms do not violate the second law of
thermodynamics.
6. Distinguish between exergonic and endergonic reactions in terms of free energy
change.
7. Explain why metabolic disequilibrium is one of the defining features of life.
8. List the three main kinds of cellular work. Explain in general terms how cells
obtain the energy to do cellular work.
9. Describe the structure of ATP and identify the major class of macromolecules to
which ATP belongs.
10. Explain how ATP performs cellular work.
Protein Enzymes Regulate Metabolic Pathways
11. Describe the function of enzymes in biological systems.
12. Explain why an investment of activation energy is necessary to initiate a
spontaneous reaction.
13. Explain how enzyme structure determines enzyme specificity.
14. Explain the induced-fit model of enzyme function.
15. Describe the mechanisms by which enzymes lower activation energy.
16. Explain how substrate concentration affects the rate of an enzyme-catalyzed
reaction.
17. Explain how temperature, pH, cofactors, and enzyme inhibitors can affect enzyme
activity.
The Control of Metabolism
18. Describe how allosteric regulators may inhibit or stimulate the activity of an
enzyme.
19. Explain how the binding of oxygen to hemoglobin illustrates cooperativity.
20. Explain how feedback inhibition prevents a cell from wasting chemical resources.
21. Describe how localization of enzymes within a cell may help order metabolism.
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Bio 2
Fall, 2010
Updated 10/7/10
CHAPTER 9 CELLULAR RESPIRATION: HARVESTING CHEMICAL
ENERGY
The Principles of Energy Harvest
1. In general terms, distinguish between fermentation and cellular respiration.
2. Write the summary equation for cellular respiration. Write the specific chemical
equation for the degradation of glucose.
3. Define oxidation and reduction.
4. Explain in general terms how redox reactions are involved in energy exchanges.
5. Describe the role of NAD+ in cellular respiration.
6. In general terms, explain the role of the electron transport chain in cellular
respiration.
The Process of Cellular Respiration
7. Name the three stages of cellular respiration and state the region of the eukaryotic
cell where each stage occurs.
8. Describe how the carbon skeleton of glucose changes as it proceeds through
glycolysis.
9. Explain why ATP is required for the preparatory steps of glycolysis.
10. Identify where substrate-level phosphorylation and the reduction of NAD+ occur
in glycolysis.
11. Describe where pyruvate is oxidized to acetyl CoA, what molecules are produced,
and how this process links glycolysis to the citric acid cycle.
12. List the products of the citric acid cycle. Explain why it is called a cycle.
13. Describe the point at which glucose is completely oxidized during cellular
respiration.
14. Distinguish between substrate level phosphorylation and oxidative
phosphorylation.
15. In general terms, explain how the exergonic “slide” of electrons down the electron
transport chain is coupled to the endergonic production of ATP by chemiosmosis.
16. Explain why ATP synthase is considered a molecular rotary motor.
17. Explain where (in what organelle) and how (across which membrane) the
respiratory electron transport chain creates a proton gradient. Explain why this
gradient is described as a proton motive force.
18. Summarize the net ATP yield from the oxidation of a glucose molecule by
constructing an ATP ledger.
19. Explain why it is not possible to state an exact number of ATP molecules
generated by the oxidation of a molecule of glucose.
Related Metabolic Processes
20. Distinguish between fermentation and anaerobic respiration.
21. State the basic function of fermentation.
22. Compare the fate of pyruvate in alcohol fermentation and lactic acid fermentation.
23. Compare the processes of fermentation and cellular respiration.
24. Distinguish between obligate and facultative anaerobes.
25. Describe the evidence that suggests that glycolysis is an ancient metabolic
pathway.
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Bio 2
Fall, 2010
Updated 10/7/10
26. Describe how food molecules other than glucose can be oxidized to make ATP.
27. Explain how glycolysis and the citric acid cycle can contribute to anabolic
pathways.
28. Explain how ATP production is controlled by the cell. Describe the role that the
allosteric enzyme phosphofructokinase plays in this feedback control.
CHAPTER 10: PHOTOSYNTHESIS
The Process that Feeds the Biosphere
1. Distinguish between autotrophic and heterotrophic nutrition.
2. Describe the structure of a chloroplast, listing all membranes and compartments.
3. Write a summary equation for photosynthesis.
4. Explain van Niel's hypothesis and describe how it contributed to our current
understanding of photosynthesis. Describe the evidence that supported his
hypothesis.
5. In general terms, explain the role of redox reactions in photosynthesis.
The Pathways of Photosynthesis
6. Describe the two main stages of photosynthesis in general terms.
7. Describe the relationship between an action spectrum and an absorption spectrum.
Explain why the action spectrum for photosynthesis differs from the absorption
spectrum for chlorophyll a.
8. Explain how carotenoids protect the cell from damage by light.
9. List the wavelengths of light that are most effective for photosynthesis.
10. Explain what happens when a solution of chlorophyll a absorbs photons. Explain
what happens when chlorophyll a in an intact chloroplast absorbs photons.
11. List the components of a photosystem and explain the function of each
component.
12. Trace the movement of electrons in linear electron flow. Trace the movement of
electrons in cyclic electron flow.
13. Explain the function(s) of linear electron flow. Explain the function(s) of cyclic
electron flow.
14. Describe the similarities and differences in chemiosmosis between oxidative
phosphorylation in mitochondria and photophosphorylation in chloroplasts.
15. State the function of each of the three phases of the Calvin cycle.
16. Describe the role of ATP and NADPH in the Calvin cycle.
Alternative Mechanisms of Carbon Fixation
17. Describe what happens to rubisco when O2 concentration is much higher than
CO2 concentration.
18. Describe the major consequences of photorespiration. Explain why it is thought
to be an evolutionary relict.
19. Describe two important photosynthetic adaptations that minimize
photorespiration.
20. List the possible fates of photosynthetic products.
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Bio 2
Fall, 2010
Updated 10/7/10
Chapter 16
DNA as the Genetic Material
1. Explain why researchers originally thought protein was the genetic material.
2. Explain how Watson and Crick deduced the structure of DNA and describe the
evidence they used. Explain the significance of the research of Rosalind Franklin.
3. Describe the structure of DNA. Explain the base-pairing rule and describe its
significance.
DNA Replication and Repair—Key FigureFig. 16.17
4. Describe the semiconservative model of replication and the significance of the
experiments of Matthew Meselson and Franklin Stahl.
5. Describe the process of DNA replication, including the role of the origins of
replication and replication forks.
6. Explain the role of DNA polymerases in replication.
7. Explain what energy source drives the polymerization of DNA.
8. Distinguish between the leading strand and the lagging strand.
9. Explain how the lagging strand is synthesized even though DNA polymerase can add
nucleotides only to the 3’ end. Describe the significance of Okazaki fragments.
10. Explain the roles of DNA ligase, primer, primase, helicase, topoisomerase, and
single-strand binding proteins.
11. Define “antiparallel” and explain why continuous synthesis of both DNA strands is
not possible.
12. Briefly explain the roles of DNA polymerase, mismatch repair enzymes, and
nuclease in DNA proofreading and repair.
13. Describe the function of telomeres.
14. Explain the possible significance of telomerase in germ cells and cancerous cells.
Bacterial and Eukaryotic Chromosomes
15. Compare a bacterial chromosome and a eukaryotic chromosome.
16. Describe how the packing of chromatin changes during the course of the cell cycle.
17. Distinguish between heterochromatin and euchromatin.
Chapter 17
The Connection between Genes and Proteins
1. Explain the reasoning that led Archibald Garrod to suggest that genes dictate
phenotypes through enzymes.
2. Distinguish between the “one gene-one enzyme” hypothesis and the “one geneone polypeptide” hypothesis and explain why the original hypothesis was
changed.
3. Explain how RNA differs from DNA.
4. Briefly explain how information flows from gene to protein. Is the central dogma
ever violated?
5. Distinguish between transcription and translation.
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Bio 2
Fall, 2010
Updated 10/7/10
6. Compare where transcription and translation occur in bacteria and in eukaryotes.
7. Define “codon” and explain the relationship between the linear sequence of
codons on mRNA and the linear sequence of amino acids in a polypeptide.
8. Explain why polypeptides begin with methionine when they are synthesized.
9. Explain what it means to say that the genetic code is redundant and unambiguous.
10. Explain the significance of the reading frame during translation.
11. Explain the evolutionary significance of a nearly universal genetic code.
The Synthesis and Processing of RNA: Key Figures  17.3, 17.10
12. Explain how RNA polymerase recognizes where transcription should begin.
Describe the role of the promoter, the terminator, and the transcription unit.
13. Explain the general process of transcription, including the three major steps of
initiation, elongation, and termination.
14. Explain how RNA is modified after transcription in eukaryotic cells.
15. Define and explain the role of ribozymes. What three properties allow some RNA
molecules to function as ribozymes?
16. Describe the functional and evolutionary significance of introns.
17. Explain why, due to alternative RNA splicing, the number of different protein
products an organism can produce is much greater than its number of genes.
The Synthesis of Protein: Key Figures17.17, 17.18, 17.19, 17.21
18. Describe the structure and function of tRNA.
19. Explain the significance of wobble.
20. Explain how tRNA is joined to the appropriate amino acid.
21. Describe the structure and functions of ribosomes.
22. Explain the statement, “A ribosome can be regarded as one colossal ribozyme.”
23. Describe the process of translation (including initiation, elongation, and
termination) and explain which enzymes, protein factors, and energy sources are
needed for each stage.
24. Describe the significance of polyribosomes.
25. Explain what determines the primary structure of a protein and describe how a
polypeptide must be modified before it becomes fully functional.
26. Describe what determines whether a ribosome will be free in the cytosol or
attached to the rough endoplasmic reticulum.
27. Define “point mutations”. Distinguish between base-pair substitutions and basepair insertions. Give an example of each and note the significance of such
changes.
28. Distinguish between a missense and a nonsense mutation.
29. Why is an insertion or deletion more likely to be deleterious than a substitution?
30. Define the term ‘mutation’. Give an example of a physical and a chemical agent
of mutation.
31. Briefly compare gene expression in bacteria, archaea and eukarya. In general, is
archaeal gene expression more similar to bacterial or eukaryotic gene expression?
32. Describe the historical evolution of the concept of a gene.
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