BIO 349 Developmental Biology (K. Kalthoff)

Exams Spring 1996

First Midterm Exam (20 February 1996)

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.

1. Bindin of sea urchin sperm is located
a. in the acrosomal vesicle
b. on the acrosomal process
c. both of the above are correct
d. none of the above is correct

2. The animal egg pole is characterized by
a. polar bodies
b. polar granules
c. both of the above are correct
d. none of the above is correct

3. The part of the mammalian blastocyst that gives rise to the embryo proper is called
a. amnion
b. inner cell mass
c. yolk sac
d. none of the above is correct

4. Nuclei from frog kidneys, upon transplantation into newt oocytes, support the synthesis of
a. frog kidney-specific proteins
b. frog oocyte-specific proteins
c. newt oocyte-specific proteins
d. all of the above are correct

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 the one odd statement, be it correct or false, and circle the respective letter.

5. Egg activation
a. The cascade of events following fertilization is called egg activation.
b. The cortical granule reaction prevents the fertilizing sperm from falling off.
c. The plasma membrane potential shifts temporarily from a negative resting potential to a positive fertilization potential.
d. The rate of protein synthesis increases as part of egg activation.

6. Cleavage Pattern
a. The cleavage pattern of an embryo is controlled by the positioning and orientation of the mitotic spindles.
b. Mitotic spindles may be attracted to particular areas of egg cortex.
c. The mitotic spindle tends to align itself perpendicular to the longest dimension of a cell.
d. The cleavage plane is always perpendicular to the axis of the mitotic spindle.

7. Induction
a. Induction is an interaction between cells or tissues that changes the determined state of at least one partner.
b. The cell (tissue) that changes its state of determination is the inducing tissue.
c. Most inductive interactions occur during oogenesis.
d. The earliest inductive event in amphibian development is neural induction.

8. Mesoderm Induction in Amphibians
a. The potency of equatorial (marginal) blastula cells to form mesodermal structures is acquired gradually during cleavage.
b. Animal cells induce their vegetal neighbors to form mesoderm.
c. Dorsal vegetal blastomeres induces neighboring equatorial cells to form notochord.
d. Dorsal equatorial cells induce their lateral neighbors to form intermediate mesoderm.

EXCHANGE WORDS (2 points per pair)

The following statements are erroneous. However, each one can be corrected by exchanging two single words. Circle these two words within each statement.

9/10. Frog oocytes synthesize large amounts of ribosomal RNA from cytoplasmic nucleoli whereas fly oocytes receive RNA and other extrachromosomal components from polyploid nurse cells.

11/12. Holoblastic eggs usually show isolecithal cleavage, whereas centrolecithal eggs have superficial cleavage.

13/14. Embryonic determination is an interaction between one (inducing) tissue and another (responding) tissue, as a result of which the responding tissue changes its state of induction.

FILL IN THE BLANKS (1 point each)

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

15/16. According to the principle of _______________ mechanisms, a given biological function may be supported by more than _______________ molecular or cellular mechanism.

17/18. Hybrid cells generated by fusing rat liver cells with _______________ fibroblasts will synthesize mouse liver enzymes, indicating that nuclear activity is controlled by the _______________ environment.

19/20. Induction promotes the process of _______________ by causing a stepwise increase in the number of _______________ states among the cells of a developing embryo.

21-30. SHORT ESSAY (max.10 points) M phase-Promoting Factor (MPF)

A. Outline in general terms the biological role and biochemical nature of MPF.
B. How do the biochemical nature and quantity of MPF change during the cell cycle?
C. How is the cyclic change of MPF modified during oocyte growth, maturation, and fertilization?

31-40. SHORT ESSAY (max. 10 points) Epidermal Compartments in Insects

A. What is a cell clone?
B. Describe the technique of somatic crossover to genetically mark clones of cells.
C. How did the use of somatic crossover in Drosophila lead to the discovery of epidermal compartments in insects? Define such compartments.

41-50. SHORT ESSAY (max. 10 points) Localized Cytoplasmic Determinants

A. Outline, with the aid of a diagram, a heterotopic transplantation experiment showing the localization of germ cell determinants near the posterior pole of Drosophila eggs.
B. What control experiments were necessary to make the results conclusive?
C. How was this experiment facilitated by the availability of genetic markers in Drosophila?

Second Midterm Exam (2 APRIL 1996)

MATCH UP (max. 10 points)

The following are lists of embryological sources (1-10) and adult derivatives (a-j). Match up by entering each letter into the space behind one number. Note that some sources may have multiple or no adult derivatives listed. Maximum 10 points.

1. ______ dermatome

2. ______ endoderm

3. ______ epidermal ectoderm

4. ______ intermediate mesoderm

5. ______ myotome

6. ______ neural crest

7. ______ notochord

8. ______ sclerotome

9. ______ somatic lateral mesoderm

10. ______ visceral lateral mesoderm

a. circulatory system

b. dorsal root ganglia

c. intervertebral disk (nucleus pulposus)

d. skeletal muscles of limbs

e. pigment cells

f. Schwann cells

g. skeletal muscles of trunk

h. hypodermis

i. smooth intestinal muscle

j. vertebrae

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.

11. A loss-of-function allele can be mimicked in transfected cells by
a. transcribing a transgene from a strong promoter
b. transcribing a "flipped gene" into "antisense RNA"
c. both of the above are correct
d. none of the above are correct

12. Differential gene expression can be shown directly by
a. in situ hybridization of a defined labeled cDNA, or anti-sense RNA, to histological sections
b. digestion with restriction enzymes
c. both of the above
d. none of the above

13. Polypeptides are directed to different cellular destinations by
a. disulfide bridges
b. initiation factors
c. signal sequences
d. spliceosomes

PICK THE ODD STATEMENT (1point 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 the one odd statement, be it correct or false, and circle the respective letter.

14. Sea Urchin Gastrulation
a. The vegetal plate invaginates to form the larval skeleton.
b. Primary mesenchyme cells ingress and later form the archenteron.
c. The archenteron elongates by convergent extension.
d. The anus is formed where the tip of the archenteron contacts the ectoderm.

15. 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 abnormal functions of genes that evolved late in the history of a phylum and modify earlier patterns of genetic control.

16. Translational Control in Eggs
a. Some mRNAs are stored inside the endoplasmic reticulum.
b. Upon egg maturation or fertilization, specific mRNAs move from subribosomal mRNP particles to polysomes.
c. Some mRNAs are recruited selectively into polysomes by differential splicing.
d. Proteins needed for vitellogenesis are synthesized selectively after fertilization.

FILL IN THE BLANKS (1 point each word)

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

17/18. In the Xenopus gastrula, the animal cap undergoes ______________ while part of the ________________ zone involutes.

19/20. Bicoid mRNA is a localized cytoplasmic _________________ that is translated into a _________________ factor.

21-30. SHORT ESSAY (maximum 10 points) Neural Induction

Describe the experiment by Hans Spemann and Hilde Mangold showing that the embryonic axis in amphibians is organized by tissue from the dorsal blastopore lip.
A. Which structures are formed by the organizing (inducing) tissue, and which structures derive from responding tissue? How could the authors distinguish between contributions from the organizing versus responding tissue?
B. How did the regional character of the induced axial structures depend on the developmental stage of the donor of the dorsal lip? How do you explain this dependence?

31-40. SHORT ESSAY (maximum 10 points) Drosophila Sexual Development

A. Which gene(s) control(s) the splicing of doublesex pre-mRNA into a female-specific or male-specific mRNA in Drosophila ?
B. Design an experiment that would demonstrate the effects of the gene(s) identified in part A on the splicing of doublesex pre-mRNA. Diagram the expected results. Hint: male specific doublesex mRNA is larger than female-specific doublesex mRNA.

41-50. SHORT ESSAY (maximum 10 points) Paragenetic Information

A. What is paragenetic information?
B. Describe a critical observation on the ciliated protozoan, Paramecium aurelia, showing that paragenetic information is passed on during cell division.

321 Final Spring 1996

MATCH UP (1 point each line)

The following is a list of embryological terms (1-10) and their definitions. Match up by entering the appropriate letters in the spaces behind the numbers.

1. ______ archenteron

2. ______ bindin

3. ______ blastocyst

4. ______ blastopore

5. ______ enhancer

6. ______ epiboly

7. ______ epigenesis

8. ______ gametes

9. ______ ingression

10. ______ polar body

a. early mammalian embryo

b. glycoprotein on acrosomal process of sea urchin sperm

c. haploid sister cell of oocyte

d. migration of cells from surface to interior of embryo

e. opening formed during gastrulation

f. primitive gut

g. progression from simple to complex organization

h. regulatory gene element

i. sex cells capable of participating in fertilization

j. spreading movement of epithelial cells to cover deeper embryonic 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 the correct one.

11. The fast block to polyspermy is based on
a. the acrosome reaction
b. the cortical reaction
c. depolarization of the plasma membrane
d. none of the above is correct

12. The dorsal vegetal blastomeres of the amphibian blastula give rise to
a. the neural plate
b. the Nieuwkoop center
c. Spemann's organizer
d. None of the above is correct

13. The middle ear ossicles of mammals originate from
a. cartilage elements supporting pharyngeal arches
b. aortic arches
c. both of the above are correct
d. none of the above are correct

14. Which of the following mammalian cells are renewed from stem cells?
a. endothelial cells
b. epidermal cells
c. female germ cells
d. hepatocytes

15. Which of the following do NOT normally occur in extracellular material?
a. collagen
b. fibronectin
c. microfilaments
d. proteoglycans

16. In mammals, the development of a male gonad requires the activity of the testis determining factor in
a. connective tissue of testis
b. pre-Sertoli cells
c. spermatogonia
d. none of the above is correct

17. The metamorphosis of holometabolous insects is controlled by
a. ecdysone
b. juvenile hormone
c. both of the above are correct
d. none of the above is correct

PICK THE ODD STATEMENT (1point 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 the one odd statement, be it correct or false, and circle the respective letter.

18. Primary and Secondary Jaw Joints
a. The primary jaws of vertebrates are derived from aortic arches.
b. The palatoquadrate and mandibular cartilages form the primary jaw joint, which persists in vertebrates except mammals.
c. A secondary jaw joint, formed by the dentary and temporal bones, has evolved in mammals.
d. A fossil mammal-like reptile, Diarthrognathus, has both the primary and the secondary jaw joint as an adult.

19. 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.

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

 21. Collagen Synthesis
a. The collagen peptide has a 3' untranslated region.
b. Most of the collagen peptide is spliced out and degraded in the endoplasmic reticulum.
c. Collagen fibers are hollow tubes consisting of globular subunits.
d. Collagen fibers self-assemble in the extracellular space.

22. Polar Coordinate Model
a. The polar coordinate model assigns positional values to cells in polar coordinates.
b. Intercalary regenerates are always derived from more distal cells.
c. The shortest intercalation rule states that the short axis of a rectangular field is restored before the long axis.
d. The polar coordinate model is based on two morphogens.

FILL IN THE BLANKS (1 point each word)

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

23/24. All vertebrates are very _______________ as advanced embryos, that is, after organogenesis; this stage is therefore known as the _______________ stage of vertebrates.

 25/26.Morphogen _______________ are attractive models because they can confer size invariance to embryonic _______________ .

27/28.The second mammalian vertebra, known as the ________________ , has a projection, the _______________ , around which the first cervical vertebra rotates.

29.30. Human XY individuals without a functional copy of the ________________ receptor gene develop as phenotypic females except that they lack the derivatives of the _______________ duct.

31-40.SHORT ESSAY (MAX. 10 POINTS) Polar Lobe

Many molluscs are characterized by the occurrence of a polar lobe during the first two cleavages.
A. Diagram the fate of the polare lobe during the first two cleavages.
B. What is the apparent function of the polar lobe?
C. Describe experimental evidence for the proposed function.

41-50.SHORT ESSAY (MAX. 10 POINTS) Involution in Xenopus gastrulae

A. Define the morphogenetic movement of involution in general terms.
B. Describe experimental results showing that involution occurs during amphibian gastrulation.
C. Name the region of the Xenopus early gastrula that involutes, and briefly characterize the fates of its components.

51-60.SHORT ESSAY (MAX. 10 POINTS) Nobel Prize 1995

A. Who won the 1995 Nobel Prize in Physiology or Medicine?
B. Summarize - on approximately one page - what the Nobel laureates discovered and which methods they used.

61-70.SHORT ESSAY (MAX. 10 POINTS) Cell Adhesion Protein

Assume you have isolated gene that encodes two alternatively spliced mRNAs, which are both translated into proteins similar to known cell adhesion molecules.
A. How would you test whether each of these proteins is necessary for cell adhesion in an epithelium where the gene is expressed?
B. How would you test whether each of these proteins is sufficient for cell adhesion in mesenchymal cells in which the gene is not normally expressed?
C. Having found that both proteins are sufficient for cell adhesion, how would you proceed to determine which protein confers the greater amount of cell adhesion?

71-80.SHORT ESSAY (MAX. 10 POINTS) Oncogenes and Proto-Oncogenes

A. What are oncogenes?
B. How does one test whether a cloned DNA segment contains an oncogene?
C. What are proto-oncogenes, and how do they differ from oncogenes?
D. What types of protein do proto-oncogenes encode?


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