P3 practice exam KEY at end PDF

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NOTE: There are no questions on morphogenesis; this is a new lecture. 1. During embryonic development, the three germs layers are created during _____. A. cleavage B. fertilization C. gastrulation D. organogenesis E. neurulation 2. Which of these events results in the movement of cells from the surface into the interior of the embryo? A. neurulation B. gastrulation C. blastula formation D. neurulation and gastrulation E. gastrulation and blastula formation 3. Which one of the following adult tissues originates from the ectoderm layer? A. Muscle B. Heart C. Nervous system D. Kidney E. None of the above 4. A small segment of tissue is removed from the posterior of the early wing bud of a donor chick embryo and transplanted to the anterior of the early wing bud of a host chick embryo. The wing of the host chick develops as a mirror image duplication of the normal wing digits (see figure). This result is caused by ____. A. a morphogen gradient B. lateral inhibition C. reaction-diffusion D. sequential induction 5. Notch-mediated lateral inhibition involves _____. A. paracrine signaling B. autocrine-signaling C. contact-dependent signaling D. endocrine signaling

6. An experimenter isolates blocks of tissue from two different regions of a blastula-stage embryo (tissue A and tissue B). She places them in separate dishes. Tissue A gives rise to skin; tissue B gives rise to endodermal-type tissue. She then isolates the same two tissues from another embryo, but this time she puts them next to each other in the same dish. Tissue B still gives rise to endodermal-type tissue but tissue A now gives rise to muscle tissue (call this tissue C). She next cuts a new block of tissue A, removes a block of the muscle tissue (tissue C) and places them next to each other in a dish. This time tissue A gives rise to nerves, whereas tissue C maintains it fate. This experiment demonstrates which of the following? A. A morphogen gradient B. Lateral inhibition C. Reaction-diffusion D. Sequential induction 7. A particular strain of E. coli contains a mutation that alters the Lac repressor so that it can no longer bind to allolactose. When these cells are grown in medium containing glucose but not lactose, the repressor _____ bind DNA and the operon _____ be expressed. A. will not, will B. will not, will not C. will, will D. will, will not 8. When E. coli cells are grown in high levels of glucose and high levels of lactose ____. A. Lac repressor binds allolactose B. CAP binds DNA C. Lac repressor binds DNA D. CAP binds cAMP 9. Sequence-specific binding of transcription regulators to DNA involves interactions between the bases in DNA and the amino acid side chains of the protein. Which one of the following amino acids would NOT be involved in these DNAGlutamic acid Leucine Lysine Serine protein interactions? A. Glutamic acid B. Leucine C. Lysine D. Serine

10. Which of the RNA polymerases can transcribe mRNAs in eukaryotic cells? A. RNA polymerase I B. RNA polymerase II C. RNA polymerase III D. RNA polymerases I and II E. All of the above 11. Which of the following are NOT bound by eukaryotic transcriptional regulators? A. histone modifying enzymes B. chromatin remodeling complexes C. other transcription regulators D. mediator E. none of the above; all can be bound 12. Which of the following statements about DNA methylation is FALSE? A. DNA methylation can be propagated by epigenetic mechanisms. B. Methylation of adenines is the most common DNA methylation in humans. C. Cytosine methylation ofen occurs within a 5′-CG-3′ sequence. D. DNA methylation at the promoter region is usually an indication that the gene is not expressed. 13. A new publication reports the finding of a novel mouse mutation in a gene called lumbar that causes the HoxC20 gene to be abnormally expressed as shown in the drawing (green area = HoxC20 expression). Assume that the regulatory elements in the HoxC cluster contain binding sites for the wildtype lumbar protein and that the mutated protein cannot bind them. What kind of transcriptional regulator is lumbar likely to be? A. A transcriptional activator B. A transcriptional repressor C. A general transcription factor D. RNA polymerase II E. Not possible to say with the information provided. 14. A particular mutation in bicoid completely eliminates its function. A female fly homozygous for this mutation is crossed to a normal male fly. What fraction of the resulting embryos will develop normally? A. 0% B. 25% C. 50% D. 100% 15. Segment polarity genes are expressed in the _____ blastoderm in _____ parasegments. A. cellular, seven B. syncytial, 14 C. syncytial, seven D. cellular, 14

16. A graduate student has found a novel fly mutation that changes the expression pattern of a gap gene. The gap protein is normally found as two broad bands, one near the anterior and one near the posterior of the embryo. In the mutant, only the anterior band is present. What type of gene might this mutation affect? A. Homeotic gene B. Pair-rule gene C. Segment polarity gene D. Egg polarity gene 17. Drosophila larvae lacking the activity of a gap gene _____. A. are missing every other segment B. are missing several adjacent segments C. have all segments, but patterning within each is segment abnormal D. have no apparent segments 18. Drosophila larvae lacking the activity of the Hox genes ____. A. have all segments, but they are all identical B. are missing every other segment C. are missing several adjacent segments D. have all segments, but patterning within each is segment abnormal 19. Which genes maintain their expression in the adult fly? A. segment polarity genes B. pair rule genes C. Hox genes D. pair rule and segment polarity genes E. segment polarity and Hox genes 20. A graduate student is studying a new Drosophila loss of function mutant that she has obtained in a mutagenesis screen and has called Tailless. She finds that in Tailless mutants the proteins Giant (shown in green), Krüpple (shown in red) and Hunchback (shown in blue) are expressed as indicated in the right column of the figure (the lef column shows the normal expression pattern of these proteins). This experiment supports the hypothesis that _____ regulates the expression of _____. A. Tailless, Krüpple B. Hunchback, Tailless C. Giant, Krüpple D. Tailless, Giant E. Hunchback, Krüpple

21. In frog embryos, specification of the vegetal pole depends on _____. A. asymmetries established before fertilization B. the point of sperm entry C. the movement of maternal determinants afer sperm entry D. none of the above 22. What is the signal sent from vegetal cells that induces animal cells to become mesoderm? A. BMP4 B. Wnt11 C. VegT D. Nodal 23. Cortical rotation following fertilization in X. laevis places the _____ pole at the point of sperm entry, while Wnt11 mRNA is transported to the _____ pole. A. anterior; posterior B. posterior; anterior C. animal; vegetal D. dorsal; ventral E. ventral; dorsal 24. A researcher injects a compound into a newly fertilized frog egg that will specifically inactivate the Wnt11 mRNA and no Wnt11 protein will be produced. Which of the follow events will this treatment NOT block? A. cortical rotation B. nervous system formation C. -catenin entry into nuclei D. formation of BMP gradients 25. In the frog embryo, the Spemann organizer produces _____ causing ectoderm tissue to become _____ cells. A. BMP4, nerve B. BMP4, epidermal C. BMP4 inhibitors, nerve D. BMP4 inhibitors, epidermal 26. Which of the following statements about adult stem cells is FALSE? A. Stem cell niches control the proliferation of precursor cells via signaling. B. Each type of stem cell gives rise to one differentiated cell type. C. A stem cell divides to create another cell like itself and a cell that will go on to differentiate. D. Although they are not terminally differentiated, they are nonetheless specialized. E. They will ofen undergo several divisions and diversifications before producing the terminally differentiated cell. 27. iPS (induced pluripotent stem) cells are made from somatic cells by __________. A. modifying them to express specific transcription factors. B. treating them with signaling molecules. C. transplanting them into a blastocyst. D. nuclear transplantation.

28. Which of the following have been used successfully to treat human diseases? A. Embryonic stem (ES) cells B. Adult stem cells C. Induced pluripotent stem (iPS) cells D. All of the above

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C D C A C D D A B B E B B A D D B A E D A D E A C B A B...