VERTEBRATE EMBRYOLOGY - BIOS 225
EXAM I
FEBRUARY 17, 2000
QUESTIONS 1-11. Place the letter corresponding to the single best FALSE answer on the answer sheet. (4 points each)
1. Which of the following statements concerning sperm capacitation is FALSE?
A. To become competent to fertilize eggs, human sperm require changes (called capacitation), which occur in the female reproductive system.
B. The process of capacitation enables the sperm to undergo the acrosome reaction and hyperactivation.
C. Recent research on capacitation by Visconti, et al. found that calcium, sodium bicarbonate and bovine serum albumin were necessary for sperm capacitation in vitro.
D. The protein ZP-3 is a required to initiate the capacitation process.
2. Hermaphrodites have many advantages such as: all individuals can bear young, one individual can colonize a new habitat, little time and energy is spent on courtship and there is no mating competition. So why are there males (and sexual reproduction)? Which of the following statements is FALSE?
A. Species must change or become extinct as proposed in the "Red Queen" hypothesis and males provide new combinations of genes which fuel those changes.
B. Males are necessary because in most sexually reproducing species, males are more flamboyant and colorful (e.g. the peacocks tail).
C. Sexual reproduction allows for the accumulation of favorable combinations of genes.
D. Sexual reproduction produces more genetic variation which allows individuals to respond better to a changing environment.
3. Which statement comparing the processes of meiosis and mitosis is False?
A. Haploid nuclei are produced during meiosis but not mitosis.
B. Chromosomes pair and genetic recombination occurs in meiosis but not mitosis.
C. In both meiosis and mitosis long periods of arrest occur in the chromosome cycle.
D. Both meiosis and mitosis occur in germ cells but not in somatic cells.
4. Which statement concerning reproduction in vertebrates is False?
A. Asexual reproduction in vertebrates does not require eggs.
B. Asexual reproduction leads to genetically identical offspring..
C. Sexual reproduction results in genetic variability of the offspring.
D. Sexual reproduction requires gametogenesis and fertilization.
5. Which statement concerning early human embryogenesis is FALSE ?
A. After cleavage the blastomeres form the trophoblast and inner cell mass of the blastula.
B. The inner cell mass forms the hypoblast and epiblast.
C. The trophoblast forms the cytotrophoblast and the syncytiotrophoblast.
D. The hypoblast develops into the placenta after gastrulation.
6. Which statement about gastrulation in birds is FALSE?
A. Mesoderm originates from epiblast cells which migrate through the primitive streak to a position between the epiblast and hypoblast.
B. Endoderm originates from epiblast cells which migrate through the primitive streak to replace the hypoblast.
C. Epiblast cells which form Hensen's node move into the embryo to form the notochord.
D. Neural crest originates from epiblast cells which move into the embryo through the primitive streak.
7. A secondary (Siamese twin) embryo was produced when Spemann and Mangold transplanted the dorsal blastopore lip of an early amphibian gastrula into the ventral region of another early gastrula embryo. Which statement about this experiment is FALSE?
A. The transplanted dorsal lip induced nearby cells to become mesoderm and involute into the embryo.
B. The dorsal lip was called the "organizer" because it organized the dorsal-ventral and anterior-posterior axes of the secondary embryo.
C. The secondary embryo was formed completely by cells derived (by cell division) from the transplanted dorsal lip.
D. The experiment suggested that cells of the dorsal lip signaled adjacent host cells to change their developmental fate (ex. from future epidermis to mesoderm and neural tube).
8. Which statement about formation of the dorsal-ventral axis and mesoderm in amphibians is False?
A. The dorsal region of the embryo develops at a site opposite to the point where the sperm enters the egg.
B. At fertilization the dorsalizing factors are activated by rotation of the cortical cytoplasm relative to the inner core of egg cytoplasm.
C. If rotation of the egg cytoplasm is prevented by UV-irradiation the a dorsal axis will form at the point of sperm entry.
D. One of the factors required to form the dorsal axis and mesoderm is the protein hormone activin.
9. Which of the following statements about fertilization in mammals is False?
A. Within one hour the zona pellucida is lost.
B. The second meiotic division of the developing egg is completed.
C. A transient increase in calcium causes a release of cortical granules from the fertilized egg.
D. The metabolism of the egg increases.
10. Which statement concerning the ovarian and uterine (menstrual) cycles is False?
A. Prior to ovulation the buildup of the uterine endometrium is regulated by estrogen.
B. Follicle stimulating hormone (FSH) acts primarily on the secondary oocyte.
C. If fertilization occurs the corpus luteum is maintained by chorionic gonadotrophin.
D. Releasing hormones are made by neurons in the hypothalamus of the brain.
11. Which statement about lutenizing hormone (LH) is False?
A. A surge of LH near the middle of the cycle is required for ovulation.
B. LH is required for completion of the first meiotic division.
C. LH converts (lutenizes) follicle cells so that they produce progesterone.
D. LH induces the RH neurons of the hypothalamus to release hormone.
QUESTIONS 12-17. Place the letter corresponding to the single best TRUE answer on the answer sheet. (4 points each)
12. What gene product, produced by the notochord is important in inducing the formation of sclerotome in the somite?
A. Hox-5
B. Pax-3
C. Sonic Hedgehog
D. Retinoic Acid
13. In vertebrates haploid spermatozoa fertilize
A. an ovum which has completed its second meiotic division.
B. a secondary oocyte arrested in metaphase of the second meiotic division.
C. a primary oocyte.
D. an oogonium.
14. Graafian follicles
A. contain a primary oocytes until just before ovulation when secondary oocytes are formed.
B. require 28 days to grow after stimulation by follicle stimulating hormone and luteinizing hormone.
C. contain the corpus luteum.
D. are present in ovaries before puberty.
15. Sertoli cells
A. mature as they move up the seminiferous epithelium with developing sperm toward the lumen of the seminiferous tubule and then are replaced by newly formed Sertoli cells.
B. develop from primordial germ cells.
C. are connected to each other by cytoplasmic bridges.
D. are somatic "nurse" cells in the adult testes which usually do not divide in adult males.
16. The acrosome
A. is necessary for sperm motility.
B. contains enzymes which degrade the coatings of the egg during fertilization.
C. becomes the golgi apparatus of the zygote after fertilization.
D. forms during the time that sperm are stored in the epididymis.
17. Which statement about gastrulation in human embryos is FALSE ?
A. Mesoderm originates from epiblast cells which migrate through the primitive streak to a position between the epiblast and hypoblast.
B. Endoderm originates from epiblast cells which migrate through the primitive streak to replace the hypoblast.
C. The notochord arises from epiblast cells which migrate to form the primitive node and then moves into the embryo.
D. The cytotrophoblast originates from cells which migrate through the primitive streak soon after it begins to regress.
Questions 18-29. On the answer sheet mark each statement True (A) or
False (E). (2 points each)
18. Oogonia originate from the germinal epithelial cells of the ovary.
19. The neurons which control the onset of puberty originate in the olfactory pit of the nose and
migrate to the brain.
20. Internal theca cells of the ovary produce testosterone.
21. The centriole of the sperm is usually lost after fertilization.
22. Sperm capacitation occurs in the vas deferens during ejaculation.
23. Fusion of the egg and sperm results in depolarization of the cell membrane of the egg.
24. The dorsal lip of the blastopore is homologous to Hensen's node.
25. The position identity of the mesoderm along the anterior-posterior axis is determined by the expression of steroid hormones.
26. The myotome will develop into the connective tissue and muscle of the head.
27. The extraembryonic mesoderm of human embryos begins to be produced before gastrulation begins.
28. All the somitomeres which form along the anterior-posterior axis are converted to somites.
29. The notochord induces the floorplate of the neural tube to produce sonic hedgehog.
Did you mark the True/False questions 18-29 True=A and False=E on your answer sheet? If not, please go back and change them.
Questions 30-33. The following statements are characteristic of which process?
Place the correct letter on the answer sheet. (2 points each)
A. spermatogenesis
B. oogenesis
C. both spermatogenesis and oogenesis.
30. Gamete production is continuous from puberty to death.
31. Genetic recombination occurs during prophase of meiosis I.
32. One functional gamete from each cell going through meiosis.
33. Primordial germ cells migrate to gonad from the endoderm of yolk sac.
BIOS 325 - VERTEBRATE EMBRYOLOGY
EXAM II, MARCH 30, 2000
Questions 1-12. Place the letter corresponding to the single best FALSE answer on the answer sheet. (4 points each)
1. Which statement about stem cells of the mammary gland is FALSE?
A. Medically, stem cells are important because they are the cells likely to develop into cancer of the breast.
B. Small light cells in the mammary epithelium usually contact the lumen.
C. Some large light cells have well developed secretory organelles and milk products at their apical surfaces.
D. Pale staining cells are the putative stem cells.
2. Which statement about the development of the atrioventricular (A-V) canal is False?
A. Initially in heart development, there is no direct flow from the atria to the right ventricle.
B. The A-V canal must shift to establish direct blood flow to the right ventricle from the atria.
C. When the A-V canal first forms it is shaped like a "dogs bone".
D. When the superior and inferior A-V endocardial cushions fuse a single A-V valve is finally formed.
3. Which statement about the head fold is FALSE ?
A. It is important in the development of the heart.
B. It is important in the formation of the foregut.
C. It is important in the development of the pharyngeal grooves and pouches.
D. It is important in the formation of the 1st aortic arch.
4. Which of the following statements about the 1st pharyngeal arch is FALSE?
A. It's endodermal lining forms the lateral portions of the thymus.
B. It is innervated by the trigeminal nerve.
C. It forms the upper jaw.
D. It forms the lower jaw.
5. Which statement about the endocardial tubes is FALSE ?
A. They form the muscle layer of the adult heart.
B. They fuse as the anterior intestinal portal moves posteriorly.
C. They are derived from splanchnic mesoderm.
D. They will form the inner lining of the adult heart.
6. Which statement concerning the development of the atrium is FALSE ?
A. Two walls (septa) form converting the single atrium to two atrial chambers.
B. Equal amounts of blood enter the right and left atria from the vena cava and the pulmonary veins, respectively.
C. The foramen ovale provides the major opening between the atria.
D. There is a flap valve in the atrial septum which closes off the foramen ovale after birth.
7. Which conclusion concerning experiments where the embryonic heart
is cut into segments is FALSE?
A. The sinus venosus segment will beat faster than the atrial segment.
B. The atrial segment has an inherent rate of beating faster than the ventricle.
C. The atrium and ventricle will not beat independently of the sinus venosus because the nerves have been severed.
D. A portion of the sinus venosus has pacemaker activity.
8. Which of the following statements about the development of the uninary system in humans is FALSE ?
A. The pronephros degenerates before it becomes functional.
B. The mesonephros degenerates before it becomes functional.
C. The duct which forms the ureter is derived from the mesonephric duct.
D. The metanephros forms last and becomes the adult kidney.
9. Which of the following statements about the development of the uninary system
in humans is FALSE?
A. Nephrotomes are derived from intermediate mesoderm.
B. The urethra is derived from the urogenital sinus.
C. The urinary bladder is derived from intermediate mesoderm.
D. The mesonephric duct is derived from intermediate mesoderm.
10. Which of the following statements about the reproductive system is False?
A. The fetal testis produces testosterone which is required for the normal transformation of the mesonephric duct.
B. The fetal testis produces anti-mullerian hormone which causes the mullerian ducts to degenerate.
C. The fetal ovary produces a hormone which causes the mesonephric duct to degenerate.
D. In the absence of testis determining factor (SRY) the gonad will become an ovary.
11. Which of the following statements about the sympathetic and parasympathetic nervous systems is False?
A. Both sympathetic and parasympathetic nervous systems have preganglionic and postganglionic neurons.
B. Postganglionic neurons develop in ganglia derived from neural crest cells.
C. Ectodermal placodes form the sensory neurons of the parasympathetic nervous system.
D. Motor fibers of preganglionic neurons develop in the neural tube.
12. Which of the following statements about spinal cord development is False?
A. When the neural tube first forms it is composed of only one cell type &endash; neuroepithelial cells.
B. Spinal cord nerves carry either sensory or motor fibers but generally not both.
C. Nuclei migrate to the inner region (near central canal) of the neuroepithelial cell to undergo mitosis.
D. The marginal zone includes the axons and dendrites of neurons and the glial cells which myelinate nerve fibers.
QUESTIONS 14-22. Place the letter corresponding to the single best TRUE answer on the answer sheet. (4 points each)
13. The dorsal root of the spinal cord
A. carries only motor fibers.
B. carries only sensory fibers.
C. carries both motor and sensory fibers.
D. A and B
E. A, B and C
14. Pharyngeal arches are derived from
A. head somitomeres.
B. neural crest.
C. splanchnic mesoderm.
D. A and B
E. A, B and C
15. The duct system of the metanephric kidney is derived from the
A. ureteric bud.
B. mesonephric diverticulum.
C. mesonephric tubule.
D. metanephrogenic blastema.
16. The complete indifferent gonad requires cells originating from the
A. splanchnic mesoderm of genital ridge.
B. intermediate mesoderm of developing mesonephros.
C. yolk sac endoderm.
D. A and B
E. A, B and C
17. Which cells produce the testis determining factor (SRY).
A. Pre-Sertoli, sex cord cells
B. Leydig cells
C. Primordial germ cells
D. A and B
E. A, B and C
18. Which cells produce anti-mullerian hormone?
A. Sertoli cells
B. Leydig cells
C. Primordial germ cells
D. A and B
E. A, B and C
19. Which cells produce the testosterone required for normal development of the male reproductive ducts?
A. Sertoli cells
B. Leydig cells
C. Primordial germ cells
D. A and B
E. A, B and C
20. The vagina is formed by the:
A. mullerian ducts
B. urogenital sinus
C. mesonephric duct
D. A and B
E. A, B and C
21. The cell bodies of motor neurons of the spinal nerves arise from the
A. ventral column.
B. marginal zone.
C. floor plate.
D. dorsal horn.
22. The amnion in the bird embryo is formed by folding of the
A. somatopleure.
B. splanchnic mesoderm.
C. endoderm.
D. epiblast.
QUESTIONS 23-28: On the answer sheet mark each statement TRUE (A) or FALSE (E). (2 points each)
23. The urogenital ridge divides the cloaca into the ureteric bud and rectum.
24. A phenotypic female (XY) will develop in the absence of functional testosterone receptors and the presence of testes which produce testosterone and anti-mullerian hormone.
25. The mapping and discovery of SRY relied heavily on evidence from XX males and XY females.
26. Preganglionic neurons of the sympathetic and parasympathetic nervous systems are derived from neural crest cells.
27. The genital tubercle forms most of the penis in males and the clitoris in females.
28. The higher centers of the brain (ex. cortex) have gray matter on the inside and white matter on the outside.
VERTEBRATE EMBRYOLOGY - BIOS 325
EXAM III
May 4, 2000
QUESTIONS 1-8. Place the letter corresponding to the single best FALSE answer on the answer sheet. (4 points each)
1. Which of the following statements about apoptosis is False?
A. It is a genetically mediated, programmed, form of cell death associated with organogenesis.
B. In the "conflict model" of Myc action it is proposed that, like an oncogene, Myc promotes cell division when mitogens are present, but if mitogens are absent it promotes apoptosis.
C. In cells whose DNA has been damaged, the levels of the tumor suppressor p53 decrease resulting in the stimulation of cell division.
D. Rb is a tumor suppressor that inhibits cell division and promotes terminal differentiation of lens cells.
2. In the midge, Wachitella persicariae, which statement about the germ plasm is False?
A. Nuclei which move into the posterior pole (germ) plasm of the egg will form functional gametes.
B. Most nuclei lose 32 out of the original 40 chromosomes, but nuclei in the pole plasm do not lose chromosomes.
C. Nuclei which are prevented from entering the pole cytoplam lose chromosomes and will not form functional gametes.
D. Nuclei which lose chromosomes but are allowed to enter the pole cytoplam will form functional gametes.
3. Which statement about the umbilical cord is FALSE ?
A. The umbilical cord is derived from the chorion.
B. Its outside surface is covered by the amniotic membrane.
C. After it first forms it contains the stalk leading to the yolk sac.
D. It contains blood vessels derived from the mesoderm of the allantois.
4. Which statement concerning the placenta is FALSE ?
A. The syncytiotrophoblast is located on the outside surface of chorionic villi.
B. The placenta is composed of a maternal component (the decidua basalis) and an embryonic component (the chorionic frondosum).
C. Mature villi lack a syncytiotrophoblast.
D. The placenta produces estrogen and progesterone which are required to maintain pregnancy.
5. Which of the following statements about the development of mammary glands and epidermal hair follicles is False?
A. Both the hair follicles and mammary glands form as downgrowths of the ectoderm.
B. Once cells of the hair follicles and mammary glands become determined (programmed) they lose the capacity to go through cell division.
C. Normal development of the hair follicles and mammary glands is dependent on signals from the underlying connective tissue.
D. Stem cells of the hair follicles and mammary glands are unipotent.
6. Which of the statements concerning the characteristics of differentiation is False?
A. Differentiated cells are often different in shape and type of organelles.
B. A unique set of housekeeping proteins is what makes cells different.
C. Differentiated cells normally lose the capacity to divide.
D. The adult program of differentiation is extremely stable.
7. Which statement about the conversion of a normal cell to a cancer cell is False?
A. The ability to control cell division is lost.
B. The ability to differentiate normally is lost.
C. Cell division is correctly regulated in benign tumor cells.
D. Malignant tumor cells have acquired the ability to escape the tissue of
origin and invade other tissues.
8. Which of the following statements about human embryonic stem cells (ESC) is False?
A. Since ESC are derived from human blastocyst embryos, before the immune system develops, they will not be rejected if transplanted to another person.
B. Biotech companies are planning to use them to produce differentiated cells that can be used to replace dying cells of human organs.
C. Biotech companies are planning to use them to produce differentiated cells that can be used to seed biodegradable matrices to form organs such as the bladder.
D. One technique to eliminate histocompatibility of ESC is to produce them using therapeutic cloning.
QUESTIONS 9-11. Place the letter corresponding to the single best TRUE answer on the answer sheet. (4 points each)
9. Which of the following cells can be used to create "immortal" stem cell lines that will differentiate into multiple cell types?
A. Primordial germ cells
B. Cells of the inner cell mass
C. Umbilical cord blood cells
D. A and B
E. A, B and C
10. What reasons do biologists give for cloning laboratory and farm animals?
A. To study how determination and differentiation can be reversed so that we can better control cancer and the regeneration of human tissues and organs.
B. To produce multiple copies of animals which have been bred, or genetically engineered to produce more or higher quality products, ex. wool and milk.
C. To produce multiple copies of transgenic animals which serve as models for studying human diseases, or produce biomedically important proteins.
D. All of the above reasons.
11. The main reason abnormal embryos are produced in nuclear transfer experiments is:
A. the genes of the donor nuclei are often lost during cell differentiation.
B. a normal embryo cannot develop without an egg nucleus.
C. reprogramming of cell division and gene expression is abnormal.
D. the abnormal embryos are haploid.
E. All of the above reasons.
Questions 12-25. On the answer sheet mark each statement True (A) or False (E). (4 points each)
12. Cell differentiation and determination are very stable processes because they result from permanent genetic changes, such as changes in DNA sequence.
13. Oncogenes normally have the opposite effect on cell division as proto-oncogenes.
14. In tumor cells, oncogenes are mutated versions of normal proto-oncogenes.
15. Tumor suppressor genes function in normal cells by slowing the rate of cell division and promoting cell differentiation.
16. Individuals with Parkinsons Disease caused by dying dopamine-producing cells, have been treated with human fetal brain cells.
17. Nuclear transfer experiments in frogs demonstrate that the developmental potential of nuclei improves as the age and state of differentiation of the donor cell increases.
18. In nuclear transfer experiments, the cytoplasm transferred with the donor nucleus into an enucleated egg has an important role in controlling early development.
19. To achieve greater success in cloning differentiated adult cell nuclei of frogs and cattle, a period of cell culture is normally required prior to nuclear transfer.
20. Nuclear transfer experiments in frogs provides evidence that all cells have the same genes.
21. The decidua are the portions of the endometrium restricted to the placenta.
22. Maternal antibodies do not pass through the placenta from the mother to the fetus.
23. The chorion is formed by the cytotrophoblast and extraembryonic mesoderm.
24. A significant portion of amnionic fluid in later pregnancy is contributed by the fetal kidneys.
25. Herceptin is an antibody to Epidermal Growth Factor Receptor that prevents EGF from binding and inducing cell division.
Did you mark the True/False questions 12-25 True=A and False=E on your answer sheet? If not, please go back and change them.
BIOS 220 - GENETICS
FINAL EXAM - JULY 24, 1998
1. Which of the following statements about Molecular Genetics is FALSE?
A. Mutations are required to identify and clone a gene.
B. Experiments are done directly with DNA.
C. Mutations can be directed to specific base pairs of a gene.
D. Large amounts of specific DNA sequences are required for experiments.
2. The wobble hypothesis involves
A. mRNA
B. rRNA
C. tRNA
D. both A and C
E. both A and B
3. Which of the following statements about the genetic code is FALSE?
A. It is a linear code with 3 nucleotides in each amino acid codon.
B. Each codon codes for more than one amino acid.
C. A given amino acid may be specified by more than one triplet codon.
D. Not all of the possible 64 codons code for amino acids - some are stop signals.
4. RNA synthesis on a DNA template is called
A. transformation
B. transfection
C. translation
D. transcription
5. Areas of a gene that are represented in the final protein product are termed
A. mutons
B. exons
C. recons
D. introns
6. Which of the following is shared by both prokaryotes and eukaryotes?
A. RNA splicing
B. introns
C. promoters
D. 5'-capping and 3'-poly A tails
7. The sigma subunit of RNA polymerase is important in initiation of RNA transcription in
A. Eukaryotes
B. Prokaryotes
C. Both A and B
D. Neither A or B
8. Three different forms of RNA polymerase exits in
A. Eukaryotes
B. Prokaryotes
C. Both A and B
D. Neither A or B
9. Most experimental evidence supports the view that mutations arise by
A. random events.
B. adaptive events.
C. lethal events.
D. none of the above.
10. Mutations are
A. heritable changes in DNA sequence.
B. heritable changes in the mRNA.
C. mistakes in the incorporation of amino acids into proteins.
D. only those heritable changes in DNA sequence which cause observable changes in phenotype.
11. Which of the statements about cystic fibrosis is FALSE?
A. The name came from fibroid cysts found in the pancreas.
B. The disease is fatal.
C. The cystic fibrosis gene codes for a digestive enzyme made in the pancreas.
D. Genetic tests for carriers are available.
12. The primary structure of a protein is represented by the
A. amino acid sequence
B. beta pleated sheet
C. three-dimensional conformation
D. alpha helix
13. Which of the following statements about prions is FALSE?
A. Prions are infectious proteins which can induce heritable alterations in normal proteins without altering the gene which codes for the normal protein.
B. Prions cause neurodegenerative diseases (spongioform encephalophies) in some mammals including humans.
C. Prions are an exception to the "Central Dogma" of molecular genetics which states that information flows one way from DNA to RNA to Protein.
D. Prions are mutant organisms which induce neurodegenerative diseases such as Creutzfeldt-Jakob Disease (CJD) in humans.
14. Which recombinant DNA library includes all sequences?
A. genomic
B. chromosome
C. cDNA
D. cRNA
15. Recombinant DNA research is dependent on
A. vectors
B. hosts
C. restriction endonucleases
D. cloning
E. all of the above
16. The polymerase chain reaction is a technique that
A. selectively replicates DNA sequences
B. selectively replicates RNA sequences
C. probes DNA
D. probes RNA
E. all of the above
17. A yeast artificial chromosome (YAC) is a useful
A. screen
B. host
C. vector
D. library
E. all of the above
18. Variable number tandem repeats (VNTRs) are
A. DNA sequences
B. tandem repeats
C. used in DNA fingerprinting
D. variable in number
E. all of the above
19. Restriction fragment length polymorphisms (RFLPs) are
A. found in eukaryotic DNA
B. used as genetic markers
C. used to construct linkage maps
D. cut by restriction endonucleases
E. all of the above
20. DNA fingerprinting depends on individual differences in
A. fingerprints.
B. short, repeated DNA sequences not necessarily part of a gene.
C. specific genes such as globin genes.
D. the sequence of amino acids.
E. all of the above
21. Which of the following are not part of organizing DNA in chromatin/chromosomes.
A. Synaptonemal Complexes
B. Nucleosomes
C. Nuclear Scaffolds
D. Histones
22. The proteins essential to the nucleosome subunit of chromatin are
A. acidic non-histone proteins
B. DNA polymerase
C. histones
D. RNA polymerases
E. all of the above
23. The effect of X-inactivation in mammals is that
A. females are mosaics for heterozygous X-linked genes
B. females are mosaics for homozygous autosomal genes
C. males are mosaics for hemizygous X-linked genes
D. males are mosaics for heterozygous autosomal genes
E. all of the above
24. An individual with XXXYY sex chromosomes will form how many Barr bodies?
A. 1
B. 2
C. 3
D. 4
25. Which of the following statements about the inactivated X chromosome is FALSE?
A. Every one of the genes in the inactivated X chromosome is not transcribed.
B. The inactivation effect is stable in all the progeny cells.
C. The inactivation is a random process.
D. Inactivated X chromosomes form Barr bodies.
26. DNA methylation may be a significant mode of genetic regulation in eukaryotes. Methylation regulates gene activity by
A. altering RNA polymerase activity by methylation
B. adding methyl groups to the cytosine of CG doublets in DNA
C. altering translational activity especially of highly methylated tRNAs
D. altering DNA polymerase activity by addition of methyl groups
E. all of the above
27. Which of the following statements about gene imprinting is correct.
A. Methyl groups are added to adenines by adenine methylase for
marking (imprinting) the gene.
B. The imprinting step occurs shortly after fertilization.
C. Only maternal genes can be imprinted.
D. The imprinted gene is usually the inactive (repressed) gene.
E. all of the above
28. The progressive restriction of future developmental capacity is
A. differentiation
B. determination
C. maternal effect
D. transdetermination
29. Homeotic mutants in Drosophila are those in which
A. position-effect is evident.
B. translocations have occurred.
C. recombination has taken place.
D. one structure is replaced with another.
30. What is the term which refers to the regulatory events which establish a specific pattern of gene activity and developmental fate for a given cell?
A. lysogenization
B. differentiation
C. determination
D. gradient regulated
31. Select the single FALSE statement about homeobox genes.
A. In Drosophila they determine the type of structure formed by segments.
B. They code for proteins which all have a conserved region called a homeodomain.
C. They are found only in invertebrates.
D. They are usually transcription factors.
32. In the early Drosophila embryo
A. more bicoid mRNA is located in posterior end.
B. more hunchback protein is located in the posterior end.
C. more nanos mRNA is located in the anterior end.
D. more bicoid protein is located in anterior end.
33. Which of the following statements about genes which regulate early Drosophila
development is FALSE?
A. Genes that control embryonic development fall into two classes: maternal genes and zygotic genes.
B. For traits controlled by maternal genes, all progeny will have the same phenotype as the mother, no matter what the genotype of the progeny is.
C. Maternal genes regulate the expression of zygotic genes.
D. Segmentation genes in Drosophila are classified as maternal genes.
34. Which cascade of gene action occurs during normal Drosophila development?
A Maternal genes, Segmentation genes, Homeotic genes, Zygotic genes
B. Maternal genes, Zygotic genes, Segmentation genes, Homeotic genes
C. Segmentation genes, Maternal genes, Homeotic genes, Zygotic genes
D. Segmentation genes, Homeotic genes, Zygotic genes, Maternal genes.
35. Oncogenes
A. are tumor suppressor genes
B. are bacterial genes
C. are derived from proto-oncogenes
D. induce uncontrolled cell proliferation
E. both C and D are correct
36. A predisposition to cancer usually implies the presence of
A. a viral infection
B. a fragile chromosome
C. a germ-line (gametic) mutation
D. an extended cell cycle
37. Cancer is best described as
A. a bacterial disease at the somatic cell level
B. an environmental disease at the somatic cell level
C. a genetic disease at the gametic cell level
D. a genetic disease at the somatic cell level
38. Which of the following are tumor suppressor genes?
A. BRCA1
B. RB
C. both A and B
D. neither A or B
39. Which of the following statements about the conversion of a normal cell to a cancer cell is FALSE?
A. The ability to control cell division is lost.
B. The ability to differentiate normally is lost.
C. Benign tumor cells have not lost the ability to control cell division or differentiation.
D. Malignant tumor cells have acquired the ability to escape the tissue of origin and invade other tissues.
40. Mutations in tumor suppressor genes
A. may be inherited.
B. may arise spontaneously after fertilization.
C. are usually recessive and both alleles must be mutated to eliminate gene function.
D. A, B and C
E. A and C