BIO 349 Developmental Biology (K. Kalthoff)

Exams Fall 1997

First Midterm Exam (2 October 1997)

EXCHANGE WORDS (Maximum 2 points each)

The following statements are erroneous. However, each one can be corrected by exchanging (swapping) two single words. Circle these two words within each statement. A hyphenated word counts as one word.

1/2. Centrolecithal cleavage is characteristic of telolecithal and meroblastic eggs, which often contain too much yolk to be cleaved completely.

3/4. Cytoplasmic transplantation and cell fusion experiments show that gene expression is controlled by the nuclear environment.

5/6. The marginal cells play a role in the initial phase of amphibian gastrulation whereas later gastrulation is driven by the involution of bottle zone cells.

MULTIPLE CHOICE (1 point each)

In the following questions or statements, circle the letter associated with the one answer or version of the statement that you consider to be correct.

7. Imaginal discs normally occur in
a. adult insects
b. amphibian neural plates
c. insect larvae
d. mammalian embryos

8. Cell determination - or the lack thereof - may be analyzed by
a. cell isolation
b. cell transplantation
c. clonal analysis
d. all of the above

9. The activity of a localized cytoplasmic determinant can be proven by
a. the unequal distribution of a visible cytoplasmic component
b. local UV irradiation
c. both of the above are correct
d. none of the above is correct

10. Which of the following regions of a Xenopus gastrula contribute to the archenteron
a. bottle cells
b. superficial layer of the involuting marginal zone
c. both of the above are correct
d. none of the above is correct

FILL IN THE BLANKS

Complete each of the following sentences by inserting one word into each blank space so that a scientifically and linguistically correct statement results. A hyphenated word counts as one word.

11/12.During holoblastic cleavage, the plane of _______________ forms perpendicular to the axis of the _______________ spindle.

13/14._______________ chromosomes originate by several rounds of chromosome _______________ without subsequent mitosis.

15/16.According to the principle of _______________ programs, cells that fail to receive a cytoplasmic determinant proceed with a developmental program that is normally carried out _______________ in the embryo.

PICK THE ODD STATEMENT (1 point each)

For the following questions, either three of the statements are correct and one is false, or three are false and one is correct. Pick out the one odd statement, be it correct or false, and circle the respective letter.

17. Determined State of Amphibian Cells
a. Pregastrula dorsal animal cells are determined to form neural plate.
b. Postgastrula dorsal animal cells are determined to form neural plate.
c. Early dorsal blastopore lip cells are determined to form anterior chordamesoderm.
d. Late dorsal blastopore lip cells are determined to form anterior chordamesoderm.

18. Compartments
a. The epidermis of Drosophila and other insects is subdivided into compartments.
b. A compartment is defined by boundaries that are not transgressed by marked cell clones.
c. Compartments are filled by a single cell clone.
d. Compartment boundaries may or may not be morphologically apparent.

19. Cytoplasmic Control Over Nuclerar Activity
a. Blastula nuclei transplanted into growing oocytes synthesize DNA.
b. Blastula nuclei transplanted into maturing oocytes form a metaphase plate.
c. Brain cell nuclei transplanted into fertilized eggs synthesize DNA.
d. Frog kidney nuclei transplanted into newt oocytes synthesize frog oocyte RNA.

20. Localized Cytoplasmic Determinants (LCDs)
a. LCDs are always associated with visible markers.
b. Local UV irradiation by itself has proven the existence of LCDs.
c. Heterotopic transplantation can show that an LCD is necessary.
d. A rescue bioassay can be used to characterize the molecular nature of an LCD.

21-30.SHORT ESSAY (Max. 10 pts.) Oocyte Maturation
A. Outline the cellular processes that are encompassed by the term ³oocyte maturation²?
B. How was the ³maturation-promoting-factor² discovered in frog oocytes?
C. How is the maturation-promoting factor of oocytes related to the M phase- promoting factor discovered in somatic cells?
D. Name the biochemical activity of maturation-promoting factor.
E. Given the biochemical nature of maturation-promoting factor named in part C, how does it promote the cellular processes outlined in part A?

31-40.SHORT ESSAY (Max. 10 pts.) Role of Bindin
A. What is bindin, and where does is naturally occur?
B. Describe an experiment demonstrating that bindin adheres to sea urchin eggs in a species-specific way.
C. Based on what you know about the slow block to polyspermy, should it make a difference whether the experiment described in part B is carried out with fertilized or with unfertilized eggs? Explain.

41-50.SHORT ESSAY (Max. 10 pts.) Three-Signal Model of Mesoderm Induction
A. Outline, with schematic drawings, the three-signal model of mesoderm induction.
B. Describe an experiment demonstrating the action of one of the three specific signals mentioned in part A.


Second Midterm Exam (4 November 1997)

MATCH UP (max. 10 points)

The following are a list of key words (1-10) used in the genetic and molecular analysis of development and a list of short descriptions or partial definitions (a-j) of these terms. Match up by entering the appropriate letters in the spaces behind the numbers.

1. _____ enhancer

2. _____ gain-of function allele

3. _____ germ line

4. _____ inner cell mass

5. _____ paragenetic information

6. _____ P element

7. _____ reporter gene

8. _____ signal sequence

9. _____ transcription factor

10. _____ transgene

a. bacterial gene spliced to eukaryotic promoter and enhancer
b. cell lineage forming gametes
c. cells forming embryo proper
d. DNA-binding protein
e. exogenous gene introduced into host genome
f. first amino acids of secreted protein
g. gene-regulatory DNA segment
h. gene that is active when or where it is normally silent
i. heritable structural organization of cells
j. mobile genetic element

MULTIPLE CHOICE (1 point each)

In the following questions or statements, circle the letter associated with the one answer or version of the statement that you consider to be correct.

11. Which of the following structures are derived from neural crest cells?
a. dorsal root ganglia
b. intervertebral discs
c. both of the above
d. none of the above

12. Embryos of fishes, amphibians, reptiles, and mammals look most similar
a. during cleavage
b. after gastrulation
c. after organogenesis
d. after formation of articulated appendages

13. Specific transcription factors interact mostly with
a. enhancers
b. initiation factors
c. introns
d. spliceosomes

14. Mechanisms of translational control include
a. masking of mRNA
b. polyadenylation of mRNA
c. both of the above are correct
d. none of the above is correct

FILL IN THE BLANKS

Complete each of the following sentences by inserting one word into each blank space so that a scientifically and linguistically correct statement results. A hyphenated word counts as one word.

15./16. The dorsoventral pattern of the spinal cord is established in response to signals from the _______________ , which induce the floor plate and, directly or indirectly, _______________ neurons.

17./18. A saturation _______________ screen can reveal virtually all _______________ involved in a biological process of interest.

PICK THE ODD STATEMENT (1 point each)

For the following questions, either three of the statements are correct and one is false, or three are false and one is correct. Pick out the one odd statement, be it correct or false, and circle the respective letter.

19. Neural Plate Formation
a. The neural plate is formed from paraxial mesoderm.
b. Neural plate cells become columnar.
c. Notoplate cells intercalate causing convergent extension.
d. The neural plate forms on the dorsal side of the embryo.

20. Atavisms
a. Atavisms are rare appearances of phylogenetically old traits in late developmental stages of more evolved species.
b. Supernumerary nipples in humans are atavistic.
c. Pharyngeal arches in humans are an example of atavism.
d. Atavisms can be interpreted as malfunctions of genes that evolved late in the history of a phylum and modify earlier patterns of genetic control.

21-30. SHORT ESSAY (Max. 10 pts.) Neural Induction
A. Draw schematic diagrams of an early and a late amphibian gastrula and show topographically the signaling pathway for neural induction at each stage. For each pathway, label the inducing and responding tissues.
B. Outline an experiment showing which pathway is of major importance in newts.
C. Describe another experiment showing that the other pathway is more important in Xenopus.
D. Which general principle is revealed by these experiments?

31-40. SHORT ESSAY (Max. 10 pts.) Alternative Splicing
A. Outline the three most common modes of alternative splicing.
B. Which of the three modes outlined in part A is used in the sex-specific splicing of Sexlethal pre-mRNA?

41-50. SHORT ESSAY (Max. 10 pts.) Self-Assembly
A. Define the term "self-assembly", pointing out how self-assembly differs from directed assembly.
B. Describe the self-assembly of a virus, including the nature of a seed structure in this case and how it was discovered.
C. Name three cell organelles that self-assemble.


Final Exam (10 December 1997)

MATCH UP (max. 10 points)

The following is a list of terms (1-10) and their descriptions (a-j). Match up by entering the appropriate letters in the spaces behind the numbers. Note that one description applies twice and one not at all.

1. ______ Antennapedia

2. ______ hairy

3. ______ collagen

4. ______ ecdysone

5. ______ fibronectin

6. ______ gynandromorph

7. ______ polar lobe

8. ______ protamin

9. ______ sarcoma

10. ______ vitellogenin

a. extracellular material
b. female-specific protein
c. homeotic gene in Drosophila
d. insect moulting hormone
e. insect showing patchwise expression of either male or female characteristics
f. pair rule gene in Drosophila
g. sperm chromosomal protein
h. translational control element
i. transient structure formed in mollusk embryos
j. tumor of connective tissue

EXCHANGE WORDS (Maximum 2 points each)

The following statements are erroneous. However, each one can be corrected by exchanging (swapping) two single words. Circle these two words within each statement. A hyphenated word counts as one word.

11/12. The cloning of ³Dolly² by fusing an enucleated cell with an epithelial egg is significant because of the prospect of genetically manipulating the nuclear donor cell before fusion.

13/14. In Drosophila, maternal effect genes control pair-rule genes, which control gap genes, which in turn control segment polarity genes.

MULTIPLE CHOICE (1 point each)

In the following questions or statements, circle the letter associated with the one answer or version of the statement that you consider to be the correct one.

15. A mutant allele that is dominant over the wild-type allele is likely to represent a
a. complete loss of function
b. gain of function
c. maternal effect gene
d. partial loss of function

16. The existence of localized cytoplasmic determinants is proven by
a. autoradiography
b. immunostaining
c. both of the above are correct
d. none of the above is correct

17. The homeodomain
a. is a DNA segment consisting of 180 nucleotide pairs
b. binds to specific DNA sequences
c. both of the above are correct
d. none of the above is correct

18. Which hormone controls the development of a testis from an indifferent gonad?
a. anti-Müllerian duct hormone
b. dihydrotestosterone
c. testosterone
d. none of the above is correct

FILL IN THE BLANKS

Complete each of the following sentences by inserting one word into each blank space so that a scientifically and linguistically correct statement results. A hyphenated word counts as one word.

19/20. The ³plasticity² of neural crest cells in transplantation experiments can be explained either by _______________ of individual cells or by a _______________ process among a mixed population of cells with various determined states.

21/22. A _______________ is an infectious protein particle causing neurodegenerative disease by _______________ assembly of host cell proteins.

23/24. According to the _______________ rule, the more 3¹ a homeotic gene is located within a complex the more _______________ begins its expression domain.

25/26. The cytoplasmic _______________ of an integrin molecule interacts with the cell¹s _______________ whereas the extracellular domain interacts with extracellular matrix molecules.

PICK THE ODD STATEMENT (1 point each)

In the following paragraphs, either three of the statements are correct and one is false, or three are false and one is correct. Pick out the one odd statement, be it correct or false, and circle the respective letter.

27. Cell Determination
a. Cell determination is characterized by the synthesis of abundant proteins.
b. The potency of undetermined cells is identical with their fate.
c. Clonal analysis can be used to assess the lack of cell determination.
d. The determined state of cells is never reversible.

28. Recapitulation
a. All vertebrates look alike during gastrulation.
b. Pharyngeal pouches extend from the endoderm of all vertebrates.
c The bones that form the middle ear ossicles in reptiles develop into the secondary jaw joint in mammals.
d. Among the adult vertebrates, fish depart furthest from the phylotypic organization.

29. Transgenic Mice
a. Transgenic mice can be generated by injecting cloned transgenes into one of the pronuclei of fertilized eggs.
b. Knock-out mice are generated by injecting P elements that are targeted to specific genes.
c. Transgenic mice can also be obtained by adding genetically transformed embryonic stem (ES) cells to blastocysts and then breeding those mice in which the added ES cells have contributed to the germ line.
d. Transformed ES cells may be equivalent to gain-of-function or loss-of-function mutants.

30. Control of Transcription
a. Transcription of eukaryotic genes is controlled by promoter and enhancer elements.
b. Promoters and enhancers are bound specifically by transcription factors.
c. Transcription factors position RNA polymerase at the transcription startpoint.
d. All cells of an organism contain the same mixture of transcription factors.

31-40. SHORT ESSAY (Max. 10 points) Synergistic Mechanisms
A. State in general terms the principle of synergistic mechanisms in development.
B. Outline two examples.
C. Speculate why synergistic mechanisms may be as frequent as they are.

41-50. SHORT ESSAY (Max. 10 pts.) Midblastula Transition
A. Which features of cleaving embryo change during midblastula-transition (MBT)?
B. Outline the function of the <