Final Exam, 2004
Fill in the blank. (2 points each) Fill in each blank with the most appropriate term. A list of terms follows this section. Every question has one, and only one, term on the list that best completes the sentence. For some questions, there may be terms not included on the list, that are equally appropriate to the one provided on the list. You will receive full credit
1. A molecule that is present in an organism or tissue as a concentration gradient and which regulates cell fate in a concentration dependent manner is called a(n) ___________________________.
2. The morphogenetic movement in which the three primary germ layers and the primitive gut are first formed is called _________________________.
3. When one cell or tissue alters the fate of another cell or tissue, it is called ____________________________.
4. Cell signals that occur over short to medium range, but do not require direct cell-cell contact are called __________________________ signals.
5. The series of molecular events that occur between the perception of a signal and the cellular response to that signal are called ________________________.
6. Whether cells bind to one another, and the strength of such binding among
cells, is determined by _____________________________ molecules.
7. The plant structure that produces leaves and other postembryonic growth is the ________________________________.
8. An amphibian optic cup is transplanted subjacent to either head ectoderm or trunk ectoderm. The head ectoderm forms a lens but the trunk ectoderm does not. We can say that the head ectoderm is __________________________
to respond to the optic cup but the trunk ectoderm is not.
9. Cells that are self-renewing (divide to produce daughter cells that replenish the population) and which produce at least one differentiated cell type are called _______________________________ cells.
10. A cell, which under appropriate conditions has the capacity to differentiate into multiple different cell fates is called __________________________.
11. An organism that is studied intensively because of its experimental advantages is called a(n) __________________________ organism.
12. The period of embryogenesis characterized by rapid cell division, with little or no intervening cell growth, is called ________________________.
13. A mutation that changes the identity of a structure to that of a homologous structure normally found in a different location is called a(n) ______________________________ mutation.
14. The morphogenetic movement that gives rise to the neural tube in vertebrates is called _________________________.
15. The gut is derived from the following primary germ layer:
shoot apical meristem
Multiple Choice. (2 points each) Choose the one best answer.
16. Bicoid mRNA is produced maternally and stored in the oocyte, but no protein is present until after fertilization. Fertilization must trigger regulation of Bicoid expression at the following level:
e) Could be any of the above
17. Cell fate along the anterior-posterior axis in segmented animals, including insects and vertebrates, is specified by
a) Hox genes
b) retinoic acid
c) the segmentation clock
d) sonic hedgehog
18. The following molecule is a key regulator of the cell cycle:
e) Cyclin dependent kinase
19. Cells that sustain extensive DNA damage are normally
a) eliminated by apoptosis
b) induced to redifferentiate
c) subject to lateral specification
d) induced to divide
e) sequestered by tumors
20. A growth factor is applied to two cell types, A and B. Cell type A responds by rapidly proliferating, cell type B undergoes apoptosis. Possible causes for this differential response could be
a) the two cell types express different receptors
b) the two cell types express different signal transduction factors
c) the two cell types express different transcription factors
d) all of the above
e) none of the above
21. In autonomous specification, cell fate is regulated by
a) diffusible signals
b) cell interactions
c) environmental cues
d) cytoplasmic determinants
e) chromatin remodeling
22. The following is a key aspect of plant development that distinguishes it from animal development
a) plant cells do not migrate extensively
b) plants have a transcriptionally active haploid phase in their life cycles
c) most plant organogenesis occurs postembryonically
d) all of the above
e) a) & c) but not b)
23. The following can lead to cancer:
a) A gain-of-function mutation in an oncogene
b) A gain-of-function mutation in a tumor suppressor
c) Activation of apoptosis
d) Cell cycle inhibition
e) All of the above.
24. A type of signaling molecule that is transported systemically and is important for coordinating developmental processes over large distances is a
a) Extracellular matrix protein
c) Juxtacrine factor
d) Paracrine factor
e) Autocrine factor
25. (8 points) Compare and contrast male and female gametogenesis in mammals. Be sure to include the following 4 points in your discussion:
a) The involvement of stem cells
b) The time during the life of the individual when gametogenesis occurs
c) The process of meiosis
d) The number of gametes produced from each spermatocyte vs. oocyte.
26. (6 points) Describe why mutations in genes required for germ cell determinants in Drosophila give a “grandchildless” phenotype.
27. (4 points) One type of familial sleep disorder in humans was found to be caused by a mutation in a cryptochrome gene. What is cryptochrome and why might this phenotype make sense?
28. (10 points) Consider why adult stem cells have received so much attention recently.
a) What are two important biological properties of adult stem cells that are central to this interest?
b) Describe one potential application of adult stem cells.
c) What is one of the current limitations of using adult stem cells?
d) Describe the ethical issues that could be circumvented by using adult stem cells instead of embryonic stem cells.
29. (9 points) Consider the role of reactive oxygen species (ROS) in aging.
a) What are ROS? Give two specific examples.
b) How are ROS produced in cells?
c) What role in the aging process are ROS believed to play?
30. (7 points) Describe stimulus dependent neural development in the mammalian visual system.
a) What happens if one of a newborn kitten’s eyes is deprived of light for 3 months?
b) What happens if both of a newborn kitten’s eyes are deprived of light for 3 months?
c) Explain these results.
31. (8 points) Describe the functions and sex-dependent differential regulation of the Drosophila Sex lethal (sxl), Doublesex (dsx), and male-specific lethal (msl) genes or gene products in sex determination and dosage compensation.