MULTIPLE CHOICE QUESTIONS 1. Inducible genes are usually actively transcribed when: A. the molecule degraded by the enzyme(s) is present in the cell. B. repressor molecules bind to the promoter. C. lactose is absent from the cell. D. quantities of precursor materials are low. E. there is no other substrate that can be used by the cell. 2. Repressible genes are usually actively transcribed when: A. repressor molecules bind to the promoter. B. the supply of the end product formed by the enzymes encoded by these genes is low. C. tryptophan accumulates in the cell. D. quantities of precursor materials are high. E. there is no other substrate that can be used by the cell. 3. In the tryptophan operon, the repressor actively binds to the operator when: A. tryptophan binds to an allosteric site on the repressor. B. tryptophan levels are low. C. lactose levels are low. D. there is a great need for proteins. E. allotryptophan levels are low. 4. camp levels decrease when. This results in of CAP. A. lactose levels increase; activation B. lactose levels decrease; inhibition C. glucose levels increase; inhibition D. glucose levels decrease; activation E. glucose levels decrease; inhibition 5. A new operon is discovered in a bacterium. The control of this operon is affected by a protein that is made by another gene, and is made in an active form that binds to the DNA near the operon to prevent transcription. This is an example of control. A. positive B. negative C. activational D. repressing E. inducing 15-1
6. The scenario in the accompanying figure reflects conditions of: A. low levels of lactose. B. high levels of lactose. C. low levels of glucose. D. high levels of glucose. E. None of these. 7. Temporal gene regulation refers to which of the following circumstances? A. Certain genes are induced only at a particular point in the life cycle. B. Certain genes are induced only in specific tissues. C. Heat-shock genes are induced during periods of temperature stress. D. Housekeeping genes are induced in response to a viral infection. E. Molecular chaperones are synthesized after heavy-metal ingestion. 8. Some eukaryotic DNA sequences act as introns in the cells of some tissues and exons in the cells of other tissues. This allows: A. prevention of harmful mutation. B. regulation of the rate of transcription. C. formation of different types of closely related proteins. D. regulation of the rate of translation. E. repression of DNA replication. 9. In eukaryotes, some DNA sequences act as introns in some cells and as exons in other cells. This is an example of. A. gene repression B. mrna splicing C. gene amplification D. differential mrna processing E. gene processing 10. Which DNA sequence below would be a palindromic sequence? A. AGCGCT B. AGCAGC C. AAAGGG D. ACACAC E. AGTCGT 15-2
11. During the preparation of a human genomic library, plasmids containing human DNA fragments are inserted into: A. compatible human cells. B. an antibiotic-resistant strain of E. coli to protect the inserted fragments. C. antibiotic-sensitive E. coli cells that become antibiotic-resistant if transformed. D. bacteriophages. E. mrna molecules. 12. The use of antibiotic medium at the end of this process: A. selects against plasmids containing human DNA fragments. B. selects for plasmids containing particular DNA fragments. C. selects for bacteria containing plasmids. D. selects for bacteria lacking plasmids. E. prevents contamination of the medium. 13. To avoid the introduction of introns into the vector, a copy of mature mrna is made, using the enzyme. A. sdna; RNA polymerase B. cdna; DNA ligase C. cdna; reverse transcriptase D. sdna; reverse transcriptase E. cdna; DNA polymerase 14. If a protein-coding gene is identified, its function can be studied by using RNA interference to. A. produce a RFLP B. produce an EST C. turn the gene on D. turn the gene off E. induce a mutation 15. Which of the following bits of information can be inferred from the ratio of differentcolored fluorescent dyes in a microarray? A. patterns of gene expression B. comparison of drug activity C. identification of disease-causing genes D. identification of disease-causing proteins E. All of these. 16. Proteomics is made complicated by the fact that: A. gene therapy is in its infancy. B. DNA sequencing requires powerful computers. C. the response to a drug varies with the individual. D. certain genes encode several different proteins. E. All of these. 15-3
17 Why is insulin produced by genetically engineered E. coli cells superior to insulin obtained from animal sources? A. Animal insulin has a shorter life span than insulin produced using recombinant DNA techniques. B. It contains human rather than animal sequences, reducing the chances of an allergic response. C. Animal insulin is more difficult to purify than is recombinantly produced insulin. D. Recombinantly produced insulin has a much higher activity level. E. Recombinantly produced insulin is easier to obtain than insulin from animals. 18. Why is human blood clotting factor VIII produced by genetically engineered bacteria better to treat hemophilia type A than the clotting factor isolated from human or animal blood? A. Recombinantly produced clotting factor has a longer shelf life than natural clotting factor. B. Clotting factor isolated from blood can transmit infectious agents. C. Clotting factor isolated from human blood can cause transfusion reactions. D. Recombinantly produced clotting factor is free of blood thinning factors. E. Natural clotting factor from blood is not very active. 19, 20. Use the figure to answer the corresponding questions. 19. The columns in the accompanying figure represent F (for female), C (for children), and M (for male). The presence of the band marked with arrow #1 shows that: A. this DNA sequence was inherited by both children from their father. B. this DNA sequence was inherited by both children from their mother. C. this DNA sequence was inherited by only one child from the father. D. this DNA sequence was inherited by only one child from the mother. E. individual M is not the father of these children. 15-4
20. The columns in the accompanying figure represent F (for female), C (for children), and M (for male). The presence of the band marked with arrow #2, shows that: A. this DNA sequence in the children is a mutation. B. this DNA sequence in the children is inherited from their mother. C. this DNA sequence in the children is inherited from their father. D. this sequence in the children is inherited from both their mother and father. E. individual F is not the mother of these children. 21. Why is it unlikely that genetically engineered strains of bacteria would pose a threat to the environment? A. Genetically engineered bacteria cannot survive exposure to UV radiation. B. Genetically engineered strains of bacteria are strictly regulated, making accidental release unlikely. C. Genetically engineered strains of bacteria cannot survive exposure to oxygen. D. Genetically engineered strains of bacteria are poor competitors of wild strains. E. Genetically engineered strains of bacteria require supplemental nutrients to survive. 22. The significance of totipotency is that: A. genes are not regularly lost during development. B. most organisms can be easily cloned. C. differentiation leads to the loss of certain genes in each cell. D. somatic cells are incapable of differentiation. E. unexpressed genes are lost during development. 23. What evidence supports the idea that some nuclei are totipotent? A. Nuclei taken from the cells of an embryonic frog can direct an egg to develop into a tadpole. B. Nuclei taken from the cells of a frog embryo can direct an egg to develop into a tadpole. C. Nuclei taken from a different species can direct a tadpole egg to develop into a normal tadpole. D. Some cells are capable of undergoing unlimited cell cycles. E. Some cells are capable of arresting their cell cycle at will. 24, 25. Use this figure to answer the corresponding questions. 24. In the accompanying figure, the purpose of growing the donor cells in nutrientlimited media is: A. to have small cells that would be easier to manipulate. B. to replicate a normal environment. C. to force the donor cell nucleus into the G 0 cell stage. D. to induce favorable mutations. E. to initiate apoptosis. 17-5
25. In the figure, the purpose of electrical shock at the stage of the process labeled A is to: A. kill the egg cell nucleus. B. initiate fusion of the two cells. C. stimulate cell division. D. induce mutations. E. None of these. 26. Which of the following statements does not present a reason that Drosophila melanogaster is a suitable research subject for developmental genetics studies? A. An abundance of developmental genes is available for study. B. An abundance of mutants is available for study. C. A new mutation can be mapped on the chromosome relatively easily. D. Flies can be easily grown in the laboratory setting. E. The control of fly development is unique and unrelated to human development. 27. In early Drosophila development, which of the following forms first? A. segmented larva B. pupa C. syncytial blastoderm D. blastocyst E. cellular blastoderm 28. What would be the consequence of removing a founder cell early in the development of Caenorhabditis? A. The organism would continue to develop normally. B. The organism would develop normally but would be slightly smaller. C. The organism would not develop at all. D. The organism would be a hermaphrodite. E. The structures that normally develop from that cell would be missing. 29. When the human gene coding for insulin is introduced into a mouse embryo, the gene is correctly expressed in the appropriate tissue. This shows that: A. tissue-specific gene expression is highly conserved during evolution. B. the introduced gene was edited by the mouse embryo for proper function. C. the introduced gene was exactly the same as the mouse gene for insulin. D. mice and humans are not closely related. E. mouse genes are not tissue specific. 17-6