Biology 4361 Name:______KEY___________Exam 2 ID#: ____________________November 10, 2005Multiple choice (one point each)1. Most cells differentiate bya. regulation of gene expression.b. loss of genetic material.c. amplification of genetic material.d. a combination of a and b.2. The loss of totipotency seen as development proceeds may be due toa. cellular senescence.b. loss of genetic information.c. the accumulation of unrepaired genetic damage.d. all of the above.3. Chromosomes may be limited in the number of times they can be replicated by a. progressive destruction of DNA polymerase binding sites.b. telomere shortening.c. kinetichore aging.d. accumulated DNA damage.4. A typical genes promoter regiona. contains binding sites for all transcription factors.b. contains the binding site for RNA polymerase II.c. contains binding sites for exonucleases.d. none of the above.5. A “weak” promotera. is a point where DNA damage typically occurs.b. exhibits slow RNA polymerase II binding.c. is subject to exonuclease attack.d. none of the above.6. The concentration of general transcription factorsa. establishes a limit on the speed of transcription.b. forces weak promoters to compete with strong promoters.c. is not considered a limiting factor for gene transcription.d. may differ by a factor of 100 depending on the cell type.7. Enhancers differ from promoters in thata. enhancers must be located in close proximity to the transcription initiation site.b. enhancers work only in the presence of promoters but promoters can work alone.c. enhancers bind RNA polymerase II more efficiently than promoters.d. none of the above.8. Histone acetylation results in a. transcriptional activity.b. transcriptional repression.c. tighter DNA-histone binding.d. none of the above.9. In Drosophila eggs the Oskar message a. is produced in the nurse cells and is transported to the anterior of the egg.b. is produced in the nurse cells and is transported to the posterior of the egg.c. is produced in the posterior of the egg and is transported to the anterior.d. is produced in the anterior of the egg and is transported to the posterior.10. Drosophila bicoida. is a posterior determinant.b. is an abdominal determinant.c. is an anterior determinant.d. none of the above.11. Drosophila mothers homozygous for bicoid lack-of-function genesa. fail to produce any embryos.b. produce “double anterior” embryos.c. produce “double posterior” embryos.d. none of the above.12. In amphibians, animal-vegetal polarity is illustrated bya. the central location of the nucleus.b. microtubule formations in the cytoplasmic cortex.c. yolk protein distributed mainly around the germinal vesicle.d. the mitochondrial cloud near the vegetal pole.13. Gray crescent formationa. predicts the future dorsal side of the embryo.b. can be prevented by UV radiation.c. is powered by microtubule bundles.d. all of the above.14. The dorsalizing proteins noggin and chordina. promote transcription of the siamois gene.b. inhibit goosecoid transcription.c. block BMP4 binding to its receptor.d. none of the above.15. Situs inversus and heterotaxis are examples of a. incomplete dorsalization.b. UV-radiation damage.c. transcription factors.d. disruption in left-right asymmetry.16. Tight junctions, basement membranes, and polarized cells are characteristics ofa. mesenchyme cellsb. epithelial cellsc. both mesenchyme and epithelial cellsd. neither mesenchyme nor epithelial cells17. Sea urchin primary large micromeres will form in sequence:a. primary mesenchyme, secondary mesenchyme, coelomic pouches.b. endoderm, archenteron, filopodia.c. primary mesenchyme, syncytium, spicules.d. endoderm, blastopore, anus.18. In protostomes, the blastopore forms the futurea. gut.b. mouth.c. anus.d. none of the above.19. The cells that will make up the ectoderm include:a. animal cap.b. animal cap, non-involuting marginal zone.c. animal cap, non-involuting marginal zone, marginal zone. d. animal cap, non-involuting marginal zone, marginal zone, bottle cells.20. The movements of the non-involuting marginal zone.a. include epiboly and convergent extension.b. elongate the embryo.c. change the embryo orientation from animal-vegetal to anterior-posterior.d. all of the above.True/False (one point each) 21. Chromosome loss or diminution explains cellular differentiation in that species. F22. The technique of serial nuclear transfer was used to clone the sheep “Dolly”. F23. The TATA box is a cis element recognized by the basal transcription factors. T24. It is common to find dimerization domains in specific transcription factors. T25. Alternative RNA splicing is common in Drosophila, but not in humans. F26. In amphibian embryos, artificial depletion of VegT results in an anteriorized embryo. T27. Cortical rotation results in movement of the cortex of about 35°. F28. FGF, TGF-$, and BMP4 are all associated with mesoderm induction. T29. Once initiated, the amphibian archenteron can form without bottle cells. T30. The first step in sea urchin gastrulation is the invagination of the vegetal plate. FShort answer (one point per blank; some blanks may require multiple words)31. The majority of transcription takes place in active chromatin, called euchromatin.32. In the frog blastula: in the absence of an inductive signal from endoderm cells, marginal zone cellswill form ectoderm.33. Typical mammalian gene have active sequences called exons and inactive sequences called introns.34. Many specific transcription factors contain ligand binding domains, and all contain DNA bindingdomains. (note - alternative answers acceptable)35.The nRNA 3' cap consists of polyadenylate, while the 5' end typically contain methylatedguanosine. 36. In amphibian eggs, the $-catenin message is uniformly distributed, but becomes concentrated on thefuture dorsal side through selected degradation.37. In sea urchins, the prospective mouth is called the stomatodeum and the prospective anus is calledthe blastopore.38. During amphibian gastrulation, migration of the deep zone cells “pulls” the involuting marginalzone cells along.39. Transplantation of the dorsal lip of the blastopore to the ventral side will cause the formation of anew dorsal axis.40. During amphibian gastrulation, the blastocoel is obliterated, while a new space, the archenteron, isformed.41. The superficial layer of the involuting marginal zone will form the roof of the archenteron duringamphibian gastrulation.Short Essay (answer any 5; use