If there are “CUES” listed within the question, please USE them and UNDERLINE them in your answer!
Chapter 16
1. In Griffith’s experiment, why was he able to rule out the possibility that the R cells could have simply used
the capsules of the dead S cells to become pathogenic? (CUE: DNA, heritable)
2. In the Hershey – Chase experiment, how would the results have been different if proteins carried the
genetic information? (CUE: bacteriophage, centrifuged, pellet, supernatant)
3. Consider a polynucleotide sequence of GAATTC. As it is written here, can you tell which is the 5’ end &
which is the 3’ end? If not then what further information do you need to identify the ends?
4. Consider the Meselson – Stahl experiment. If they had first grown the cells in 14N-containing medium &
then moved them to 15N-containing medium before taking samples, what would the results have been?
Please draw the tubes of these results.
5. What is the relationship between DNA replication & the cell cycle? (CUES: mitosis, sister chromatids, S
phase)
6. Use Figure 16.13 to explain what is meant when we say that each DNA strand has directionality? (CUES:
5’, 3’, phosphate group, hydroxyl group, nucleotide, deoxyribose, monomer)
7. Also, use Figure 16.13 to explain the exergonic & endergonic reactions shown in the energy coupling reaction
of DNA synthesis. (CUES: nucleoside triphosphate, hydrolysis, dNTPs)
8. Figure 16.16 highlights the “left-hand” replication fork of a replication bubble. Use this figure as a
reference to draw the right-hand fork of this replication bubble. Include each of the molecules present in
Figure 16.16 and a description of their role in DNA replication. Please remember that DNA is anti-parallel.
(CUES: primase, helicase, single-strand binding protein, RNA primer, DNA polymerase, ligase)
9. Use Figure 16.17 to describe how DNA is repaired. (CUES: ligase, nuclease, DNA polymerase, enzymes)
10. Use Figure 16.18 to describe how telomeres are replicated & why they shorten in the somatic cells of an
adult. (CUES: 3’, 5’, DNA polymerase, primer, antiparallel, telomerase)
Chapter 18
1. Most biologists now believe that viruses evolved from other living organisms recently and are not an ancient
form of life. Describe THREE pieces of evidence that viruses have evolved from other living organisms.
2. Use Figures 18.6 & 18.7 to compare & contrast the lytic & lysogenic cycles of bacteriophages. (CUES:
transcription, translation, degradation, lysis, prophage)
3. Use Figure 18.10 to explain how a retrovirus like HIV reproduces. (CUES: provirus, translation, reverse
transcriptase, vesicles, capsids, envelope)
4. Compare & contrast viroids & prions. (CUES: protein structure, RNA)
5. Describe the 3 ways genetic recombination can occur in bacteria. (CUES: transformation, Griffith,
transduction, phage, mating bridge, conjugation)
6. Use Figure 18.21 & 18.22 to explain a repressible & an inducible operon, respectively. (CUES: coding
sequence, upstream, promoter, RNA polymerase, operator, repressor, inducer, transcription, translation)
7. Use Figure 18.22: Genetic mutations are useful in analyzing the control of gene expression. In the lac
operon of E. coli, gene i codes for the repressor protein, Plac is the promoter, o is the operator, and z is
the first structural gene. (+) means wild-type; (-) means mutant. Fill in the table below by writing “YES” or
“NO” in the box, describing the level of transcription in different genetic and environmental conditions.
Z TRANSCRIPTION LEVEL
GENOTYPE
LACTOSE PRESENT
LACTOSE ABSENT
i- Plac+ o+ z+
i+ Plac+ o+ zi+ Plac- o+ z+
i+ Plac+ o- z+
8. How does cAMP regulate gene activity (Fig. 18.23)? (CUES: RNA polymerase, lac promoter, CAP, cAMP,
transcription)
Chapter 21
1. Using Figure 21.10, what would happen if a mutation in the myoD gene resulted in a MyoD protein that could
not activate the myoD gene? (CUES: transcription, translation, muscle cells, differentiation)
2. As you learned in Chapter 12, mitosis gives rise to two daughter cells that are genetically identical to the
parent cell. Yet you, the product of many mitotic cell divisions, are not composed of identical cells. Why?
(CUES: differentiation, stem cells, morphogenesis, activators)
3. In Figure 47.25 (Chapter 47), the transplanted dorsal lip caused the recipient tissue to become something
else it otherwise would not have become. What does this indicate? (CUES: ligand, transduction pathway,
transcription, translation, differentiation, embryonic organizer, induction)
4. In Figure 21.11b, the lower cells are synthesizing signaling molecules, where as the upper cells are
expressing receptors for those molecules. In terms of gene regulation, explain how these cells came to
synthesize different molecules. (CUES: promoter, transcription, translation, transcription factors,
activator molecules, gene)
5. Figure 21.14 shows the importance of morphogen gradients during development. Predict what would happen
if researchers injected bicoid mRNA into the anterior end of an egg from a female with a mutation
disabling the bicoid gene.
6. The DNA sequences called homeoboxes, which help homeotic genes in animals direct development, are
common to flies, mice and humans. Given this similarity, explain why these animals are so different from
each other? (CUES: non-homeobox, genome)
7. C. elegans is a model organism for studying apoptosis in the development of animals. Explain the importance
of apoptosis in the development of multicellular organisms. (CUES: morphogenesis, cell death, cancer)
Can Credit Question
The cassava mosaic virus (CMV) affects the cassava plant, which is the 3 rd largest carbohydrate source for the
human diet worldwide. Briefly research CMV and discuss the PRIMARY HOST, SYMPTOMS, MODE OF
TRANSMISSION, METHODS OF CONTROL, and ECONOMIC LOSSES CAUSED BY CMV.