Test Bank for Chapter 22: Developmental Genetics and ImmunogeneticsMultiple-Choice Questions1. Which of the following genes determine the identity of individual segments during development?a. bicoidb. nanosc. cactusd. dishevelede. dorsalAnswer: dSection: 22.2Comprehension Question2. The product of the bicoid gene is critical for the establishment of __________ structures in the Drosophila embryo.a. anteriorb. posteriorc. dorsald. ventrale. segmentsAnswer: aSection: 22.2Comprehension Question3. Which of the following order of gene groups is CORRECT for normal Drosophila development? 1. Gap genes2. Homeotic genes3. Pair-rule genes4. Segment-polarity genes5. Egg-polarity genesa. 1, 2, 3, 4, 5b. 4, 2, 5, 1, 3c. 3, 1, 2, 5, 4d. 5, 2, 4, 3, 1e. 5, 1, 3, 4, 2Answer: eSection: 22.2Comprehension Question4. Which of the following statements about homeotic genes is INCORRECT?a. Homeotic genes were first identified in invertebrates, but their homologues were found inalmost all organisms.b. All homeotic genes contain consensus sequence that result in specific DNA-binding motif.c. In vertebrates, homeotic genes are organized into two distinct clusters.d. All homeotic genes encode transcription factors that direct further gene expression. e. Homeotic genes exhibit a relationship between their order on the chromosome and the timing of their expression.Answer: cSection: 22.2Comprehension Question5. Which group of genes specifies the identities of individual body segments?a. Homeoticb. Gap c. Hoxd. Pair-rulee. Segment-polarityAnswer: cSection: 22.2Comprehension Question6. Activin is a protein that normally exists in a gradient within certain tissues in developing embryos. Certain undifferentiated cells cultured without activin produce epidermal cells. However, activin induces these same cells to adopt other fates (e.g., blood, muscle, heart), depending on the concentration of activin. Based on these observations, activin acts as a(n)a. transcription factor.b. cell-surface receptor.c. morphogen.d. second messenger.e. activator.Answer: CSection: 22.2Comprehension Question7. Which of the following choices lists the CORRECT sequence of gene expression during Drosophila development?1. Segmentation genes2. Egg-polarity genes3. Homeotic genesa. 1, 2, 3b. 2, 3, 1c. 2, 1, 3d. 3, 2, 1e. 3, 1, 2Answer: CSection: 22.2Comprehension Question8. Which of the following paring of genes and developmental processes is INCORRECT?a. bicoid and nanos—anterior posterior axisb. antennapedia complex—head and anterior thoracic segmentc. cactus and toll—dorsal developmentd. hunchback—ventral developmente. bithorax complex—posterior thoracic and abdominal segmentAnswer: dSection: 22.2Comprehension Question9. Which of the following statements about Hox genes is CORRECT?a. All Hox genes found in organisms other than Drosophila have a conserved pattern of identical clustered arrangements.b. When a vertebrate Hox gene is moved to a new location within the Hox gene complex, the timing of its expression gets altered.c. The Hox genes encode transcription factors that help to determine the identity of the bodyregion.d. They are usually organized as clusters and the order on the chromosome is important for their expression pattern.e. The recent studies suggest the role of miRNA in controlling the expression of some Hox genes.Answer: aSection: 22.2Comprehension Question10. Epigenetic changes in development is important in that the gene expression of cells that makeup a particular organ or tissue type is often defined by epigenetic markers. Which of thefollowing epigenetic regulations is known to cause more long-term gene silencing during the course of development? a. Chromatin remodelingb. DNA methylationc. Histone modificationsd. None of the above can cause long-term gene silencing.Answer: bSection: 22.2Comprehension Question11. Which of the following groups of gene is directly regulated by egg-polarity genes?a. Homeoticb. Gap c. Hoxd. Pair-rulee. Segment-polarityAnswer: bSection: 22.2Application Question12. The Bicoid protein in fruit flies specifies anterior development. In the absence of Bicoid protein in an egg, the embryo will develop two tails. The bcd− mutation is recessive and exhibits a maternal effect. Which of the following correctly describes the embryos produced from a cross between a bcd+/ bcd− male and a bcd−/bcd− female?a. All embryos will be normal.b. All embryos will have two tails.c. Three-fourths of the embryos will have two tails.d. One-half of the embryos will have two tails.e. One-fourth of the embryos will have two tails.Answer: bSection: 22.2Application Question13. In wild-type flowering plants, carpel development is determined by what class of gene products?a. A gene productsb. A + B gene productsc. B + C gene productsd. C gene productse. A + C gene productsAnswer: dSection: 22.3Comprehension Question14. A flower is made up of four concentric rings of modified leaves called whorls. Which of the following lists the individual whorls in correct order going from the outside towards the inside of the flower?a. Petals, sepals, carpels, and stamens b. Sepals, petals, stamens, and carpelsc. Carpels, stamens, petals, and sepalsd. Stamens, carpels, sepals, and petalse. Carpels, petals, sepals, and stamensAnswer: bSection: 22.3Comprehension Question15. The diagram below illustrates the normal expression of three different groups of genes (A, B,and C) within four different whorls of a developing flower. Normally, whorl 1 produces sepals, whorl 2 produces petals, whorl 3 produces stamens, and whorl 4 produces carpels. Furthermore, expression of class A genes inhibits class C genes, and expression of class C inhibits class A.What kind of mutation would produce sepals in whorls 1 and 4 and petals in whorls 2 and 3?a. Defective in A b. Defective in Bc. Defective in Cd. Defective in A and Be. Defective in B and CAnswer: cSection: 22.3Application Question16. The diagram below illustrates the normal expression of three different groups of genes (A, B,and C) within four different whorls of a developing flower. Normally, whorl 1 produces sepals, whorl 2 produces petals, whorl 3 produces stamens, and whorl 4 produces carpels. Furthermore, expression of class A genes inhibits class C genes, and expression of class C inhibits class A.What kind of mutation would produce carpels in whorls 1 and 4 and stamens in whorls 2 and 3?a. Defective in A b. Defective in Bc. Defective in Cd. Defective in A and Be.