Name Class Date SEC T I O N 11 - 1 R E VIEW C ONTROL OF G ENE E XPRESSION VOCABULARY REVIEW Explain the relationship between the terms in each of the following pairs of terms. 1. regulator gene, repressor protein 2. operator, operon 3. intron, exon 4. transcription factor, enhancer MULTIPLE CHOICE Write the correct letter in the blank. Copyright © by Holt, Rinehart and Winston. All rights reserved. 1. A gene is expressed when it is a. b. c. d. present in the genome of an individual. prevented from interacting with RNA polymerase. transcribed into mRNA. duplicated during the replication of DNA. 2. In the lac operon of E. coli, lactose functions as a. a promoter. b. an operator. c. a repressor protein d. an inducer. 3. In eukaryotic cells, transcription occurs a. on parts of the DNA that are uncoiled. b. only on introns. c. only on exons. d. on all parts of the DNA. 4. Unlike gene expression in prokaryotes, gene expression in eukaryotes a. b. c. d. cannot be regulated before transcription has occurred. can be regulated after transcription has occurred. does not involve promoters. involves the transcription of groups of genes called operons. 5. Enhancers a. code for proteins called inducers. b. must be located close to the genes they activate. c. are found only in prokaryotic genomes. d. facilitate transcription by binding to transcription factors. Modern Biology Study Guide 57 Name Class Date SHORT ANSWER Answer the questions in the space provided. 1. What is an operon, and in what type of organism are operons found? 2. Describe what occurs during activation of the lac operon. 3. Describe what occurs during repression of the lac operon. 4. Critical Thinking How does the absence of a nuclear envelope in prokaryotes prevent prokaryotes from controlling gene expression by modifying RNA after transcription? STRUCTURES AND FUNCTIONS Use the figure to answer the following questions. 1. The diagram below represents the lac operon in the presence of lactose. Label each part of the diagram in the space provided. b c Structural genes RNA polymerase e a 2. If the regulator gene were deleted, how would this affect expression of the structural genes? Explain your answer. 3. Is transcription of the structural genes activated or repressed under the conditions shown above? Explain your answer. 58 Section 11-1 Review Copyright © by Holt, Rinehart and Winston. All rights reserved. d Name Class Date SEC T I O N 11 - 2 R E VIEW G ENE E XPRESSION IN D EVELOPMENT AND C ELL D IVISION VOCABULARY REVIEW Distinguish between the terms in each of the following pairs of terms. 1. homeobox, homeotic gene 2. proto-oncogene, oncogene 3. sarcoma, lymphoma Copyright © by Holt, Rinehart and Winston. All rights reserved. 4. oncogene, tumor-suppressor gene MULTIPLE CHOICE Write the correct letter in the blank. 1. The expression of different genes in different cells of a multicellular organism a. b. c. d. contributes to the development of form in an organism. causes the uncontrolled proliferation of cells. is caused by the transfer of cells from one organism to another. results from mutations that destroy normal gene functioning. 2. Homeoboxes are a. found only in prokaryotes. b. found only in Drosophila. c. mutations that can have devastating consequences on development. d. DNA sequences that regulate patterns of development. 3. The major distinguishing characteristic of cancer is a. uncontrolled cell division. b. production of viruses. c. metastasis. d. tumor formation. 4. More than 85 percent of all lung cancers are caused by a. asbestos. b. tobacco smoke. c. X rays. d. ultraviolet light. Modern Biology Study Guide 59 Name Class Date 5. A gene whose normal function is to prevent uncontrolled cell division is a. an oncogene. b. a cancer gene. c. a homeotic gene. d. a tumor-suppressor gene. SHORT ANSWER Answer the questions in the space provided. 1. How do homeotic genes regulate development in Drosophila? 2. What factors influence whether a person will develop cancer? 3. How can viruses induce cancer? 4. What are two key characteristics of cancer cells? 5. Critical Thinking A great deal of research on the causes of and a possible cure for cancer focuses on the genes that control the cell cycle. Why? Tumor-suppressor genes Proto-oncogenes Normal Effect: 60 Section 11-2 Review Mutations Effect: Normal Effect: Copyright © by Holt, Rinehart and Winston. All rights reserved. STRUCTURES AND FUNCTIONS Complete the flowchart below by filling in the three boxes at the bottom.