Oral Path Chapter 6 multiple choice
Genetic heterogeneity can cause amelogenesis imperfecta because of its inheritance pattern (X-linked, autosomal recessive, or autosomal dominant). a. Both the statement and reason are correct and related. b. Both the statement and reason are correct but not related. c. The statement is correct, but the reason is not. d. The statement is not correct, but the reason is correct. e. Neither the statement nor the reason is correct.
A. Genetic heterogeneity can cause amelogenesis imperfecta because of its inheritance pattern (X-linked, autosomal recessive, or autosomal dominant).
Hypohidrotic ectodermal dysplasia is characterized by: a. hypodontia, hypotrichosis, and hypohidrosis. b. hyperdontia, hypotrichosis, and hypohidrosis. c. hypodontia, hypertrichosis, and hyperhidrosis. d. hyperdontia, hypertrichosis, and hyperhidrosis.
A. Hypohidrotic ectodermal dysplasia is characterized by hypodontia (partial anodontia), hypotrichosis (less than normal amount of hair), and hypohidrosis (abnormally diminished secretion of sweat). Some patients die of hyperthermia (greatly increased body temperature) after prolonged exposure to the sun or heavy exercise.
During meiosis, when chromosomes that were crossing over do not separate, and both migrate to the same cell, resulting in a germ cell with an extra chromosome, this is referred to as: a. nondisjunction. b. chiasmata. c. translation. d. alleles.
A. Nondisjunction occurs when chromosomes that were crossing over do not separate, and both migrate to the same cell.
Which of the following statements is true regarding management of patients with cyclic neutropenia? a. Preventive antibiotic therapy is instituted to protect against secondary opportunistic infections. b. Treatment should be done when the circulating neutrophil count is low to reduce the risk of complications such as gingival hemorrhage and secondary infection. c. Dental hygiene care increases the risk of opportunistic infections in patients with cyclic neutropenia. d. Patients are treated periodically with vitamin D to reduce symptoms.
A. Preventive antibiotic therapy is instituted to protect against secondary opportunistic infections.
Telangiectasias of the oral mucosa for a patient with hereditary hemorrhagic telangiectasia will be especially prominent on the: a. tip and anterior dorsum of the tongue. b. palate. c. gingiva. d. buccal mucosa.
A. Telangiectasias of the oral mucosa for a patient with hereditary hemorrhagic telangiectasia will be especially prominent on the tip and anterior dorsum of the tongue. The palate, gingiva, and buccal mucosa are often affected but to a lesser degree. Hemorrhage from sites in the oral cavity, mainly the lips and tongue, is second in frequency to epistaxis.
The areas of bony radiolucency seen in cherubism: a. resemble a central giant cell granuloma when seen under the microscope. b. occur in place of the teeth, and radiographs will reveal complete anodontia. c. will increase in size as the patient matures, even until the seventh or eighth decade of life. d. will resolve, leaving the patient without any sign of facial deformity later in life.
A. The areas of bony radiolucency seen in cherubism resemble a central giant cell granuloma when seen under the microscope. The bone lesions interfere with tooth development and eruption.
The _____ type of amelogenesis imperfecta is characterized by tooth enamel that does not develop to a normal thickness because of failure of the ameloblasts to lay down enamel matrix properly. a. hypoplastic b. hypocalcified c. hypomaturation d. hypoplastic-hypomaturation
A. The hypoplastic type of amelogenesis imperfecta is characterized by tooth enamel that does not develop to a normal thickness because of failure of the ameloblasts to lay down enamel matrix properly.
Which of the following clinical syndromes caused by gross chromosomal abnormalities is associated with bilateral cleft lip and palate, microphthalmia or anophthalmia, and polydactyly? a. Trisomy 13 b. Trisomy 21 c. Turner syndrome d. Klinefelter syndrome
A. Trisomy 13 is associated with bilateral cleft lip and palate, microphthalmia or anophthalmia, superficial hemangioma of the forehead or nape of the neck, growth retardation, severe mental retardation, polydactyly of the hands and feet, clenching of the fist with the thumb under the fingers, rocker-bottom feet, heart malformations, and several anomalies of the external genitals.
Which of the following types of RNA carries the message for translation of DNA to ribosomes in the cytoplasm? a. mRNA b. tRNA c. rRNA d. hnRNA
A. mRNA carries the message for transcription of DNA to ribosomes in the cytoplasm.
A codon in DNA is formed by a sequence of _____ bases. a. two b. three c. four d. six
B. A codon in DNA is formed by a sequence of three bases. It encodes an amino acid.
A karyotype containing XXXY indicates _____ syndrome. a. Down b. Klinefelter c. Turner d. cri du chat
B. A karyotype containing XXXY indicates Klinefelter syndrome.
A patient with Papillon-Lefèvre syndrome will show a marked gingivoperiodontal inflammatory condition in the primary teeth at about _____ years of age. a. 0 to 0.5 b. 1.5 to 2 c. 4 to 6 d. 8 to 9
B. A patient with Papillon-Lefèvre syndrome will show a marked gingivoperiodontal inflammatory condition in the primary teeth at about 1.5 to 2 years of age. It is marked by edema, bleeding, alveolar bone resorption, and mobility of teeth with consequent exfoliation. At about 8 or 9 years of age, the gingivoperiodontal destruction of the permanent dentition is repeated in the same manner as occurred in the primary dentition. All primary teeth are lost before 14 years of age.
A patient with _____ will have a mouth that appears fishlike, with downward sloping of the lip commissures. a. osteogenesis imperfecta b. mandibulofacial dysostosis c. cherubism d. cleidocranial dysplasia
B. A patient with mandibulofacial dysostosis will have a mouth that appears fishlike, with downward sloping of the lip commissures. The facies shows downward sloping of the palpebral fissures, a hypoplastic nose, hypoplastic malar bones with hypoplasia or absence of the zygomatic process, abnormal and misplaced ears, and a receding chin. The lower eyelids show a cleft of the outer third, with a lack of lashes medial to it. The ears may exhibit tags, which on occasion can also be seen near the angle of the mouth
According to the Lyon hypothesis, during the early period of embryonic development, the: a. genetic activity of both of the X chromosomes in each cell of a female embryo is inactivated. b. genetic activity of one of the X chromosomes in each cell of a female embryo is inactivated. c. genetic activity of the Y chromosome in each cell of a male embryo is inactivated. d. inactivated chromosome forms a structure known as the pronucleus.
B. According to the Lyon hypothesis, during the early period of embryonic development, the genetic activity of one of the X chromosomes in each cell of a female embryo is inactivated.
After metaphase of the first meiotic division: a. the chromosomes split at the centromere and separate from one another. b. the chromosomes do not split at the centromere but separate from one another. c. each member of the pair migrates to one of the new cells, each of which contains 46 chromosomes but twice the final amount of DNA. d. each member of the pair migrates to one of the new cells, each of which contains 23 chromosomes but half the final amount of DNA.
B. After metaphase of the first meiotic division, the chromosomes do not split at the centromere but separate from one another. Each member of the pair migrates to one of the new cells, each of which contains 23 chromosomes but twice the final amount of DNA.
Characteristic radiographic oral findings of hypophosphatemic vitamin D-resistant rickets include: a. obliterated pulp chambers. b. large pulp chambers with very long pulp horns. c. normal pulp chambers with nonexistent roots. d. large pulp chambers with nonexistent pulp horns.
B. Characteristic radiographic oral findings of hypophosphatemic vitamin D-resistant rickets include large pulp chambers with very long pulp horns. In addition, the dentin exhibits pronounced cracks that extend to the dentinoenamel junction. These cracks induce fracture of the enamel with microexposure of the pulp and subsequent pulpal infection.
Chromosomes line up at the equatorial plate during the _____ stage of mitosis. a. telophase b. metaphase c. prophase d. anaphase
B. Chromosomes line up at the equatorial plate during the metaphase stage of mitosis. During metaphase chromosomes are actually formed by two identical vertical halves, each composed of either left or right, short and long arms and half of the centromere.
Cyclic neutropenia is: a. characterized by episodes that generally persist for 21 to 27 days. b. characterized by oral manifestations consisting of severe ulcerative gingivitis or gingivostomatitis. c. caused by a deletion on the long arm of chromosome 11 regions 14-21. d. inherited as an autosomal recessive condition.
B. Cyclic neutropenia is characterized by oral manifestations consisting of severe ulcerative gingivitis or gingivostomatitis.
_________ is a consistent feature of mandibulofacial dysostosis. a. Hypertrichosis b. Deafness c. Hypertelorism d. Kyphoscoliosis
B. Deafness is a consistent feature of mandibulofacial dysostosis.
During translation: a. polypeptides form an amino acid, and one or more amino acids form a protein. b. amino acids form a polypeptide, and one or more polypeptides form a protein. c. proteins form a polypeptide, and one or more polypeptides form an amino acid. d. amino acids form a protein, and one or more proteins form a polypeptide.
B. During translation, amino acids form a polypeptide, and one or more polypeptides form a protein.
Which of the following syndromes is characterized by a fusion of the anterior portion of the maxillary gingiva to the upper lip from canine to canine? a. Osler-Rendu-Parkes Weber syndrome b. Ellis-van Creveld syndrome c. Gorlin syndrome d. Peutz-Jeghers syndrome
B. Ellis-van Creveld syndrome is characterized by a fusion of the anterior portion of the maxillary gingiva to the upper lip from canine to canine.
Features of second meiosis include: a. a replication of DNA before initiation. b. essentially a mitotic division in which each chromosome splits longitudinally. c. formation of four cells from the parent cell. d. the formation of 2n DNA.
B. Features of second mitosis include essentially a mitotic division in which each chromosome splits longitudinally.
For autosomal-dominant inheritance, _____ pertains to the degree to which an individual is affected. a. penetrance b. expressivity c. heterogeneity d. consanguinity
B. For autosomal-dominant inheritance, expressivity pertains to the degree to which an individual is affected.
For parents who are carriers of the same recessive trait, the chance of having an affected child is _____%. a. 0 b. 25 c. 50 d. 100
B. For parents who are carriers of the same recessive trait, the chance of having an affected child is 25%. The risk of having a homozygotic normal child is 25%, and the chance of having a heterozygotic carrier is 50% for each pregnancy.
If both loci for blood are AO, the a. person is said to have blood group O. b. person is said to have blood group A. c. person would be homozygous. d. characteristic is recessive.
B. If both loci for blood are AO, the person is said to have blood group A.
Which is true about making a karyotype? a. Arginine may be used to arrest the mitosis of leukocytes at metaphase. b. Colchicine may be used to arrest the mitosis of leukocytes at metaphase. c. Colchicine may be used to arrest the mitosis of red blood cells at anaphase. d. It is used to evaluate molecular abnormalities in chromosomes.
B. In making a karyotype colchicine may be used to arrest the mitosis of leukocytes at metaphase.
Each of the following statements is true regarding focal palmoplantar and gingival hyperkeratosis except one. Which one is the exception? a. Marked hyperkeratosis follows the normal contour of the gingiva. b. The free gingiva is highly affected with hyperkeratosis. c. Oral changes start in childhood and increase with age. d. Oral hyperkeratinization is bandlike and a few millimeters in width
B. In patients with focal palmoplantar and gingival hyperkeratosis, the free gingiva is not affected.
Intestinal polyps seen with Peutz-Jeghers syndrome are: a. associated with inevitable malignant transformation into adenocarcinomas. b. hamartomas. c. caused by the adenomatous polyposis coli (APC) gene located on the long arm of chromosome 5. d. associated with osteomas in various bones, especially the frontal bones, mandible, and maxilla.
B. Intestinal polyps seen with Peutz-Jeghers syndrome are hamartomas.
Most cases of Down syndrome are associated with: a. maternal consumption of alcohol. b. late maternal age at the time of conception. c. estrogen supplements. d. inhalation of vapors from volatile substances.
B. Most cases of Down syndrome are associated with late maternal age at the time of conception. It is the most frequent of the trisomies.
Multiple mucosal neuroma syndrome includes multiple mucosal neuromas, medullary carcinoma of the thyroid gland, and: a. telangiectases. b. pheochromocytoma. c. gastrointestinal polyposis. d. blue sclera.
B. Multiple mucosal neuroma syndrome includes multiple mucosal neuromas, medullary carcinoma of the thyroid gland, and pheochromocytoma. The mucosal neuromas are prominent on the lips and the anterior dorsal surface of the tongue. They generally appear in the first few years of life. Medullary carcinoma of the thyroid has been diagnosed in more than 75% of patients with this syndrome; it generally develops in the second decade of life. Metastatic lesions develop frequently, and about 20% of patients die as a consequence of metastasis.
__________ is an inherited disorder affecting the gingiva and periodontium, which is characterized by hyperkeratosis of the palms of the hands and soles of the feet. a. Cyclic neutropenia b. Papillon-Lefèvre syndrome c. Gingival fibromatosis d. Laband syndrome
B. Papillon-Lefèvre syndrome is an inherited disorder affecting the gingiva and periodontium, which is characterized by hyperkeratosis of the palms of the hands and soles of the feet.
Radicular dentin dysplasia is characterized by teeth with _____ crowns and _____ roots. a. normal; normal b. normal; abnormal c. abnormal; normal d. abnormal; abnormal
B. Radicular dentin dysplasia is characterized by teeth with normal crowns and abnormal roots.
The gap 2 (G2) phase of mitosis: a. begins when mitotic division ends. b. ends when mitotic division begins. c. precedes the S phase. d. is when replication of DNA takes place
B. The G2 phase of mitosis ends when mitotic division takes place and follow the S phase. Replication of DNA takes place in the S phase
The basic defect found with radicular dentin dysplasia seems to lie in the: a. stellate reticulum. b. epithelial root sheath. c. stratum intermedium. d. dental papilla.
B. The basic defect found with radicular dentin dysplasia seems to lie in the epithelial root sheath. This guides the formation of the root.
The correct order for the stages of mitosis is: a. prophase, anaphase, metaphase, telophase. b. prophase, metaphase, anaphase, telophase. c. prophase, metaphase, telophase, anaphase. d. metaphase, prophase, telophase, anaphase.
B. The correct order for the stages of mitosis is prophase, metaphase, anaphase, telophase. During prophase the chromosomes are lining up toward metaphase; in metaphase, the chromosomes stain intensely and are arranged almost symmetrically at both sides of the center of the cell; in anaphase and telophase the chromatids are in the process of splitting.
Which of the following statements about the hereditary opalescent form of dentinogenesis imperfecta is true? a. It is associated with taurodontic teeth. b. Teeth have bulbous crowns with a color that varies from opalescent brown to brownish blue. c. Large pulp chambers and root canals are seen on radiographs. d. Roots are long and thick with periapical radiopacities.
B. The hereditary opalescent form of dentinogenesis imperfecta is associated with teeth that have bulbous crowns with a color that varies from opalescent brown to brownish blue.
A man's X chromosome is transmitted to _____ of his daughters and _____ of his sons. a. none; none b. none; all c. all; none d. all; all
C. A man's X chromosome is transmitted to all of his daughters and none of his sons. The X chromosome in his sons comes from the mother. Consequently, no male-to-male transmission of X-linked traits occurs.
A mother who is a carrier of an X-linked recessive trait has a 50% risk of having a(n): a. affected son or daughter. b. carrier son or daughter. c. affected son or a carrier daughter. d. carrier son or an affected daughter
C. A mother who is a carrier of an X-linked recessive trait has a 50% risk of having an affected son or a carrier daughter. Both daughters and sons have a 50% risk of getting the X chromosome with the gene for that condition.
A patient with Ellis-van Creveld syndrome will: a. show polydactyly on the radial side of the forearm. b. be a midget. c. lack an anterior maxillary vestibular sulcus. d. lack a posterior mandibular sulcus.
C. A patient with Ellis-van Creveld syndrome will lack an anterior maxillary vestibular sulcus
The gap 1, S, and gap 2 phases are part of what type of cell division? a. First meiosis b. Second meiosis c. Mitosis d. Hypohidrosis
C. After each cell division is completed and before the next division can occur, the cell enters the gap 1 phase, which is followed by the S phase, in which replication of the DNA takes place. The gap 2 phase follows the S phase and ends when mitotic division begins.
Cases of facial clefting occur in about 1 in _____ births. a. 80 b. 200 c. 800 d. 2000
C. Cases of facial clefting occur in about 1 in 800 births. The majority of cases of facial clefting are multifactorial in origin. A large number of inherited syndromes can include cleft lip and palate or isolated cleft palate as a component.
Which of the following statements is correct concerning chromosomes? a. They are located in the cytoplasm of the cell. b. Mature germ cells (ova and spermatozoa) contain 46 chromosomes. c. Chromosomes can only be seen clearly under a microscope when the nucleus and cell are dividing. d. Chromosomes contain RNA, which directs the production of amino acids, polypeptides, and proteins by the cell.
C. Chromosomes can only be seen clearly under a microscope when the nucleus and cells are dividing
Early diagnosis of pheochromocytoma is imperative because of the high malignant potential of: a. squamous cell carcinoma. b. basal cell carcinoma. c. thyroid carcinoma. d. osteogenic sarcoma.
C. Early diagnosis of pheochromocytoma is imperative because of the high malignant potential of thyroid carcinoma. Pheochromocytoma itself is a benign neoplasm that generally develops in ganglia around the adrenal glands. The tumor is often bilateral and is responsible for night sweats, high blood pressure, and episodes of severe diarrhea. The pheochromocytoma induces increased urinary levels of epinephrine and other substances.
Which of the following disorders affecting the jaw bones and facies is characterized by fusion of the anterior portion of the maxillary gingiva to the upper lip from canine to canine? a. Gardner syndrome b. Mandibulofacial dysostosis c. Ellis-van Creveld syndrome d. Cherubism
C. Ellis-van Creveld syndrome is characterized by fusion of the anterior portion of the maxillary gingiva to the upper lip from canine to canine. This syndrome has an autosomal-recessive inheritance pattern. The gene for thissyndrome has been mapped to the short arm of chromosome 4 region 16.
Euploid, polyploid, and aneuploid are all terms relating to a(n) _____ of chromosomes. a. alteration in the structure b. abnormal rearrangement c. alteration in the number d. duplication
C. Euploid, polyploid, and aneuploid are all terms relating to an alteration in the number of chromosomes.
Frontal bossing, depressed nasal bridge, protuberant lips, and almost complete lack of scalp hair are characteristic of a person with: a. hypophosphatemic vitamin D-resistant rickets. b. hypophosphatasia. c. hypohidrotic ectodermal dysplasia. d. dentin dysplasia.
C. Frontal bossing, depressed nasal bridge, protuberant lips, and almost complete lack of scalp hair are characteristic of a person with hypohidrotic ectodermal dysplasia. The hair that is present is usually blond, short, fine, and stiff. The skin is soft, thin, and very dry. Sebaceous glands are also lacking.
Genes that are located at the same level in homologous chromosomes and that dictate the same functions or characteristics are called: a. consanguineous. b. chromatids. c. alleles. d. precocious.
C. Genes that are located at the same level in homologous chromosomes and that dictate the same functions or characteristics are called alleles.
Hard, dense, cortical bone on the buccal aspect of the alveolar ridge by tooth number 14 would be termed a: a. radiolucent torus palatinus. b. radiopaque torus mandibularis. c. radiopaque exostosis. d. radiolucent exostosis.
C. Hard, dense, cortical bone on the buccal aspect of the alveolar ridge by tooth number 14 would be termed a radiopaque exostosis. They are generally asymptomatic unless traumatized. They may be single, multiple, unilateral, and bilateral and occur less frequently than either palatal or mandibular tori.
Hypophosphatasia is characterized by: a. an increase in serum alkaline phosphatase levels. b. abnormal formation of enamel and dentin. c. exfoliation of teeth without evidence of periodontal or gingival disease. d. an autosomal-dominant inheritance pattern.
C. Hypophosphatasia is characterized by exfoliation of teeth without evidence of periodontal or gingival disease. The basic defect in this condition is a decrease in serum alkaline phosphatase levels with increased urinary and plasma levels of phosphoethanolamine. Agenesis or abnormal formation of cementum in these patients leads to spontaneous premature shedding of primary teeth, especially mandibular incisors.
In DNA a sequence of thymine, adenine, and cytosine (TAC) is always matched by: a. adenine, cytosine, and guanine (ACG). b. guanine, adenine, and cytosine (GAC). c. adenine, thymine, and guanine (ATG). d. a five-carbon sugar and a phosphate.
C. In DNA a sequence of thymine, adenine, and cytosine (TAC) is always matched by adenine, thymine, and guanine (ATG). The base adenine is always bound to the base thymine, and guanine is always bound to cytosine.
Oral manifestations of nevoid basal cell carcinoma syndrome consist of multiple cysts of the jaws that are: a. central giant cell granulomas. b. peripheral giant cell granulomas. c. odontogenic keratocysts. d. calcifying epithelial odontogenic tumors.
C. Oral manifestations of nevoid basal cell carcinoma syndrome consist of multiple cysts of the jaws that are odontogenic keratocysts. These cysts vary in size; they can be very large and have a marked tendency to recur after surgical removal. On occasion, an ameloblastoma arises in them as part of this syndrome. They develop as early as 5 to 6 years of age in some affected patients and interfere with normal development of the jawbones and teeth.
pegged or absent maxillary lateral incisors: a. affect the secondary but not primary dentition. b. have a prevalence of 10% in the white population. c. are accompanied by congenitally lacking premolar teeth in 10% to 20% of the population. d. are generally an autosomal-recessive trait with variable expressivity.
C. Pegged or absent maxillary lateral incisors are accompanied by congenitally lacking premolar teeth in 10% to 20% of the population.
Points of contact between the chromatid of one chromosome and the chromatid of the other chromosome of a pair, where crossing over and exchange of chromosome segments occur, are called: a. first meiosis. b. second meiosis. c. chiasmata. d. interpolation.
C. Points of contact between the chromatid of one chromosome and the chromatid of the other chromosome of a pair, where crossing over and exchange of chromosome segments occur, are called chiasmata. This special aspect of the first meiosis takes place at metaphase.
Snow-capped amelogenesis imperfecta is a variation of type _____ amelogenesis imperfecta. a. I: hypoplastic b. II: hypocalcified c. III: hypomaturation d. IV: hypoplastic-hypomaturation
C. Snow-capped amelogenesis imperfecta is a variation of type III: hypomaturation amelogenesis imperfecta. It is characterized by a hypomaturation of the surface enamel of the occlusal third of all teeth in both dentitions. The maxillary teeth are more severely affected with this whitish discoloration. The enamel in those areas is of regular hardness and smooth. It does not fracture or chip from the crown.
6. __________ is characterized by very large, pyramid-shaped molars with large pulp chambers. a. Amelogenesis imperfecta b. Dentinogenesis imperfecta c. Taurodontism d. Dentin dysplasia
C. Taurodontism is characterized by very large, pyramid-shaped molars with large pulp chambers. The furcation of the roots is displaced apically, and these teeth are classified according to the degree of furcation displacement. It is frequently found in Klinefelter syndrome and is associated with many other syndromes as well.
Genetic risk is a mathematical estimate of probability governed by chance. A condition having autosomal-dominant inheritance is transmitted vertically from one generation to the next with males affected more than females. a. Both statements are true. b. Both statements are false. c. The first statement is true; the second is false. d. The first statement is false; the second is true.
C. The first statement is true; the second statement is false. Males and females are equally affected
The majority of patients with Turner syndrome have a _____ phenotype and _____ chromosomes. a. male; 47 b. female; 46 c. female; 45 d. male; 44
C. The majority of patients with Turner syndrome have a female phenotype, and in the majority of cases, the karyotype has the normal 44 autosomal chromosomes and only one X chromosome. A normal female would have two X chromosomes: one from the mother and one from the father. Most cases of Turner syndrome are caused by nondisjunction of the X chromosome in the paternal gamete.
The primary dentition of a patient with coronal dentin dysplasia will appear: a. normal. b. opaque with an amber color. c. translucent with an amber color. d. translucent with a blue color.
C. The primary dentition of a patient with coronal dentin dysplasia will appear translucent with an amber color. Radiographs show a lack of pulp chambers and small root canals. Permanent teeth present normal crown formation with normal color. Radiographs show thistle-shaped pulp chambers in single-rooted teeth and a bow-tie appearance of the pulp chambers of permanent molars.
White sponge nevus is characterized by a white, corrugated, soft, folding oral mucosa always affecting _____ mucosa. a. attached b. lingual c. buccal d. tonsillar
C. White sponge nevus is characterized by a white, corrugated, soft, folding oral mucosa always affecting buccal mucosa. The lesions are bilateral in most patients. The whitening is produced by a thick layer of keratin, which at times desquamates and leaves a raw mucosal surface.
A patient with unilateral or bilateral aplasia of the clavicles will: a. have hyperplastic paranasal sinuses. b. have a short and wide neck. c. have a mushroom shape of the cranium because of premature closure of the fontanelles. d. be able to approximate his or her shoulders to the midline.
D. A patient with unilateral or bilateral aplasia of the clavicles will be able to approximate his or her shoulders to the midline. Various other bone anomalies can also be present.
Which of the following statements is true regarding gross chromosomal abnormalities involving alterations in the number of human chromosomes? a. Aneuploidy is a complete second set of chromosomes, meaning a total of 46. b. Polyploidy is any number of chromosomes that do not represent an exact multiple of the total chromosome complement. c. Euploidy is a complete second set of chromosomes, meaning a total of 46. d. Aneuploidy may be represented by trisomy and monosomy.
D. Aneuploidy may be represented by trisomy (a pair with an identical extra chromosome) and monosomy (a missing chromosome from a pair).
Blood group _____ is an example of gene codominance. a. O b. A c. B d. AB
D. Blood group AB is an example of gene codominance. A and B are dominant over O; but when A and B are allelic, the result is blood group AB in which both genes are exhibited.
Cherubism: a. is inherited as an autosomal-dominant disease with marked penetrance in females and variable expressivity and incomplete penetrance in males. b. most frequently involves the maxilla. c. is characterized by a unilateral facial deformity. d. reveals a typical "soap-bubble" or multilocular appearance on radiographs.
D. Cherubism reveals a typical "soap-bubble" or multilocular appearance on radiographs. It usually occupies the ascending ramus of the mandible and extends into the molar and premolar areas.
Each of the following statements about chromosomes is true except one. Which one is the exception? a. Chromosomes are located in the nucleus of the cell. b. Hereditary units called genes are found on chromosomes. c. Chromosomes can only be seen clearly under a microscope when the nucleus and cell are dividing. d. Chromosomes contain RNA, which directs the production of amino acids, polypeptides, and proteins by the cell.
D. Chromosomes contain DNA, which directs the production of amino acids, polypeptides, and proteins by the cell.
For autosomal-dominant inheritance: a. males will be affected more often than females. b. the risk of having an affected offspring is 25% when a person has a gene for the condition. c. all of the offspring will be affected by a condition that is transmitted by autosomal-dominant inheritance. d. an individual can carry a gene with a dominant effect without presenting any clinical manifestation
D. For autosomal-dominant inheritance, an individual can carry a gene with a dominant effect without presenting any clinical manifestations.
Which of the following syndromes is characterized by intestinal polyps, which become malignant at age 30 and after? a. Osteogenesis imperfecta b. Nevoid basal cell carcinoma syndrome c. Mandibulofacial dysostosis d. Gardner syndrome
D. Gardner syndrome is characterized by intestinal polyps, which become malignant at age 30 and after. It is also known as familial colorectal polyposis. Polyposis primarily affects the colon and rectum and generally develops before puberty. Some authors recommend intestinal resection when the polyps appear because their malignant transformation into adenocarcinoma is invariable, especially with increasing age.
Gingival and periodontal disease has been reported in _____% of individuals with Down syndrome. a. 10 b. 25 c. 50 d. 90
D. Gingival and periodontal disease has been reported in 90% of individuals with Down syndrome. Premature loss of teeth is seen frequently. Hypodontia, abnormally shaped teeth, and anomalies in eruption with malposition and crowding of teeth are common findings.
Neurofibromatosis of von Recklinghausen is characterized by: a. multiple neurofibromas appearing as macules of various sizes. b. inevitable malignant transformation. c. oral involvement in about 90% of patients. d. café au lait pigmentation of the skin in 90% of patients.
D. Neurofibromatosis of von Recklinghausen is characterized by café au lait pigmentation of the skin in 90% of patients.
Which of the following syndromes is characterized by multiple melanotic macular pigmentations of the skin and mucosa, which are associated with gastrointestinal polyposis? a. Osler-Rendu-Parkes Weber syndrome b. Van der Woude syndrome c. Gorlin syndrome d. Peutz-Jeghers syndrome
D. Peutz-Jeghers syndrome is characterized by multiple melanotic macular pigmentations of the skin and mucosa, which are associated with gastrointestinal polyposis.
Primitive germ cells have _____ chromosomes and are called _____. a. 23; diploid b. 46; haploid c. 23; haploid d. 46; diploid
D. Primitive germ cells havd 46 chromosomes and are called diploid, with two chromosomes for each pari.
Ribonucleic acid (RNA) contains uracil rather than the base _____ found in DNA. a. adenine b. guanine c. cytosine d. thymine
D. RNA contains uracil rather than the base thymine found in DNA. RNA also differs from DNA in that it is usually single-stranded, and its sugar is a ribose rather than the deoxyribose found in DNA.
The basic defect responsible for osteogenesis imperfecta is produced by various mutations affecting the genes that encode type I collagen, resulting in: a. lack of otic ossicles. b. unilateral or bilateral aplasia or hypoplasia of clavicles. c. overgrowth of cortical bone in the midline of the palate. d. abnormally formed bones that fracture easily.
D. The basic defect responsible for osteogenesis imperfecta is produced by various mutations affecting the genes that encode type I collagen, resulting in abnormally formed bones that fracture easily.
Which of the following statements is true of oogenesis? a. Oogenesis starts around the time of puberty. b. The second meiosis is completed at the beginning of ovulation. c. Nondisjunction is more prevalent in male spermatogenesis than in female oogenesis. d. The older the woman, the greater the chance of shedding a trisomic ovum.
D. The older the woman, the greater the chance of shedding a trisomic ovum.
Inactivation of the genetic activity of one of the X chromosomes in each cell of a female embryo during the early period of embryonic development is referred to as: a. Barr body. b. nucleotide. c. karyotype. d. the Lyon hypothesis.
D. This inactivation of one of the X chromosomes in a female embryo was postulated by Mary Lyon and is known as the Lyon hypothesis
Which of the following statements is true concerning hemophilia A? a. It is inherited as an X-linked dominant condition. b. It is inherited as a Y-linked recessive condition. c. All X chromosomes are abnormal in the female carrier. d. Female carriers tend to bleed more than usual after extraction of teeth or scaling and curettage.
Female carriers tend to bleed more than usual after extraction of teeth or scaling and curettage.
Murray-Puretic-Drescher syndrome is also known as: a. cherubism. b. gingival fibromatosis with multiple hyaline fibromas. c. gingival fibromatosis with hypertrichosis, epilepsy, and mental retardation syndrome. d. Laband syndrome.
Murray-Puretic-Drescher syndrome is also known as gingival fibromatosis with multiple hyaline fibromas.