Chapter 18 Review Worksheet

Name: Chapter 18-Review WS Multiple Choice Identify the choice that best completes the statement or answers the question. 1) Which of the following is a protein produced by a regulatory gene? A) operon B) inducer C) promoter D) repressor 2) Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation? A) inducer B) promoter C) transcription factor D) CAMP 3) The lactose operon is likely to be transcribed when A) there is more glucose in the cell than lactose B) there is glucose but no lactose in the cell. C) the cyclic AMP and lactose levels are both high within the cell D) the cAMP level is high and the lactose level is low 4) Transcription of structural genes in an inducible operon A) occurs continuously in the cell B) starts when the pathway's substrate is present C) starts when the pathway's product is present D) stops when the pathway's product is present 5) Altering patterns of gene expression in prokaryotes would most likely serve an organism's survival by A) organizing gene expression, so that genes are expressed in a given order B) allowing each gene to be expressed an equal number of times C) allowing an organism to adjust to changes in environmental conditions D) allowing environmental changes to alter a prokaryote's genome 6) In positive control of several sugar-metabolism-related operons, the catabolite activator protein (CAP) binds to DNA to stimulate transcription. What causes an increase in CAP activity in stimulating transcription? A) an increase in glucose and an increase in CAMP B) a decrease in glucose and an increase in CAMP C) an increase in glucose and a decrease in CAMP D) a decrease in glucose and a decrease in the repressor 7) What would occur if the repressor of an inducible operon were mutated so that it could not bind the operator? A) irreversible binding of the repressor to the promoter B) reduced transcription of the operon's genes C) continuous transcription of the operon's genes D) overproduction of catabolite activator protein (CAP) 8) According to the lac operon model proposed by Jacob and Monod, what is predicted to occur if the operator is removed from the operon? A) The lac operon would be transcribed continuously. B) Only lacz would be transcribed. C) Only lacy would be transcribed. D) Galactosidase permease would be produced, but would be incapable of transporting lactose. 9) Imagine that you've isolated a yeast mutant that contains histones resistant to acetylation. What phenotype do you predict for this mutant? A) The mutant will grow rapidly. B) The mutant will require galactose for growth. C) The mutant will show low levels of gene expression. D) The mutant will show high levels of gene expression. 10) The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different A) genes B) regulatory sequences C) sets of regulatory proteins D) promoters 11) Not long ago, it was believed that a count of the number of protein-coding genes would provide a count of the number of proteins produced in any given eukaryotic species. This is incorrect, largely due to the discovery of widespread A) chromatin condensation control B) transcriptional control C) alternative splicing D) translational control 12) Which of the following mechanisms is (are) used to coordinate the expression of multiple, related genes in eukaryotic cells? A) Environmental signals enter the cell and bind directly to promoters. B) The genes share a single common enhancer, which allows appropriate activators to turn on their transcription at the same time. C) The genes are organized into a large operon, allowing them to be coordinately controlled as a single unit. D) A single repressor is able to turn off several related genes. 13) Steroid hormones produce their effects in cells by A) activating key enzymes in metabolic pathways B) activating translation of certain mRNAs C) promoting the degradation of specific mRNAs D) binding to intracellular receptors and promoting transcription of specific genes Use this information to answer the question(s) below. A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. 14) In one set of experiments she succeeded in increasing acetlylation of histone tails. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin condensation C) decreased binding of transcription factors D) inactivation of the selected genes 15) At the beginning of this century there was a general announcement regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes. Many people were surprised that the number of protein-coding sequences was much smaller than they had expected. Which of the following could account for much of the DNA that is not coding for proteins? A) DNA that consists of histone coding sequences B) DNA that is translated directly without being transcribed C) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function D) non-protein-coding DNA that serves as binding sites for reverse transcriptase Use this information to answer the question(s) below. A researcher introduces double-stranded RNA into a culture of mammalian cells and can identify its location or that of its smaller subsections experimentally, using a fluorescent probe. 16) Your brother has just purchased a new plastic model airplane. He places all the parts on the table in approximately the positions in which they will be located when the model is complete. His actions are analogous to which process in development? A) morphogenesis B) determination C) differentiation D) pattern formation 17) If a Drosophila female has a homozygous mutation for a maternal effect gene, A) she will not develop past the early embryonic stage B) all of her offspring will show the mutant phenotype, regardless of their genotype C) only her male offspring will show the mutant phenotype D) only her female offspring will show the mutant phenotype 18) In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated? A) genes coding for enzymes that act in the colon B) genes involved in control of the cell cycle C) genes that are especially susceptible to mutation D) genes of the bacteria, which are abundant in the colon 19) The protein of the bicoid gene in Drosophila determines the of the embryo. A) anterior-posterior axis B) anterior-lateral axis C) posterior-dorsal axis D) posterior-ventral axis 20) Which of the following types of mutation would convert a proto-oncogene into an oncogene? A) a mutation that blocks transcription of the proto-oncogene B) a mutation that creates an unstable proto-oncogene mRNA C) a mutation that greatly increases the amount of the proto-oncogene protein D) a deletion of most of the proto-oncogene coding sequence 21) The product of the p53 gene A) inhibits the cell cycle B) slows down the rate of DNA replication by interfering with the binding of DNA polymerase C) causes cells to reduce expression of genes involved in DNA repair D) allows cells to pass on mutations due to DNA damage 22) BRCAI and BRCA2 are considered to be tumor-suppressor genes because A) their normal products participate in repair of DNA damage B) the mutant forms of either one of these prevent breast cancer C) the normal genes make estrogen receptors D) they block penetration of breast cells by chemical carcinogens