Deck 6: Genetics

Question 1

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.

Answer 1

adenine, thymine, and guanine (ATG).

Question 2

Which type of RNA carries the message for translation of DNA to ribosomes in the cytoplasm?

A) mRNA
B) tRNA
C) rRNA
D) hnRNA

Answer 2

mRNA

Question 3

Genes that are located at the same level in homologous chromosomes and that dictate the same functions or characteristics are termed

A) consanguineous.
B) chromatids.
C) alleles.
D) precocious.

Answer 3

alleles.

Question 4

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.

Question 5

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.

Question 6

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.

Question 7

Primitive germ cells have _____ chromosomes and are termed _____.

A) 23; diploid
B) 46; haploid
C) 23; haploid
D) 46; diploid

Question 8

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 manifestations.

Question 9

Which clinical syndrome 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

Question 10

Which statement 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.

Question 11

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.

Question 12

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 termed

A) first meiosis.
B) second meiosis.
C) chiasmata.
D) interpolation.

Question 13

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.

Question 14

Which statement 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.

Question 15

The majority of patients with Turner syndrome have a _____ phenotype and _____ chromosomes.

A) male; 47
B) female; 46
C) female; 45
D) male; 44

Question 16

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.

Question 17

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.

Question 18

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.

Question 19

Which statement is correct concerning chromosomes?

A) Chromosomes are located in the 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.

Question 20

The gap 2 (G?) 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.

Question 21

Which statement 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.

Question 22

Telangiectasias of the oral mucosa for a patient with hereditary hemorrhagic telangiectasia will be especially prominent in which location?

A) Tip and anterior dorsum of the tongue
B) Palate
C) Gingiva
D) Buccal mucosa

Question 23

Which disorder 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

Question 24

Hard, dense, cortical bone on the buccal aspect of the alveolar ridge near the maxillary first molar would be termed a

A) radiolucent torus palatinus.
B) radiopaque torus mandibularis.
C) maxillary exotosis.
D) radiolucent exostosis.

Question 25

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.

Question 26

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.

Question 27

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.

Question 28

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.

Question 29

Which statement 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.

Question 30

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.

Question 31

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.

Question 32

A mother who is a carrier of an X-linked recessive trait has a 50% risk of giving birth to 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.

Question 33

A patient with Ellis-van Creveld syndrome will

A) show polydactyly on the radial side of the forearm.
B) be a little person.
C) lack an anterior maxillary vestibular sulcus.
D) lack a posterior mandibular sulcus.

Question 34

A patient with unilateral or bilateral aplasia of the clavicles will have which characteristics?

A) Hyperplastic paranasal sinuses
B) Short and wide neck
C) Mushroom shape of the cranium because of premature closure of the fontanelles
D) Be able to approximate their shoulders to the midline

Question 35

Which syndrome 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

Question 36

Which syndrome 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

Question 37

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 radiographic images.

Question 38

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.

Question 39

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.

Question 40

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

Question 41

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.

Question 42

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.

Question 43

The basic defect found with radicular dentin dysplasia lies in the

A) stellate reticulum.
B) epithelial root sheath.
C) stratum intermedium.
D) dental papilla.

Question 44

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.

Question 45

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.

Question 46

Each statement 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.

Question 47

Chromosomes line up at the equatorial plate during the _____ stage of mitosis.

A) telophase
B) metaphase
C) prophase
D) anaphase

Question 48

During meiosis, if chromosomes crossing over do not separate and both migrate to the same cell, a germ cell with an extra chromosome results. What is the term to describe this occurrence?

A) Nondisjunction
B) Chiasmata
C) Translation
D) Alleles

Question 49

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.

Question 50

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.

Question 51

Which statement 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.

Question 52

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.

Question 53

Snow-capped amelogenesis imperfecta is a variation of type _____ amelogenesis imperfecta.

A) I: hypoplastic
B) II: hypocalcified
C) III: hypomaturation
D) IV: hypoplastic-hypomaturation

Question 54

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

Question 55

Each statement 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.

Question 56

Frontal bossing, depressed nasal bridge, protuberant lips, and almost complete lack of scalp hair are characteristic of a person with which condition?

A) Hypophosphatemic vitamin D-resistant rickets
B) Hypophosphatasia
C) Hypohidrotic ectodermal dysplasia
D) Dentin dysplasia

Question 57

Which syndrome 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

Question 58

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

Question 59

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.

Question 60

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.

Question 61

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

Question 62

For autosomal-dominant inheritance, _____ pertains to the degree to which an individual is affected.

A) penetrance
B) expressivity
C) heterogeneity
D) consanguinity

Question 63

__________ is characterized by very large, pyramid-shaped molars with large pulp chambers.

A) Amelogenesis imperfecta
B) Dentinogenesis imperfecta
C) Taurodontism
D) Dentin dysplasia

Question 64

Gingival and periodontal disease has been reported in _____% of individuals with Down syndrome.

A) 10
B) 25
C) 50
D) 90

Question 65

A karyotype containing XXXY indicates _____ syndrome.

A) Down
B) Klinefelter
C) Turner
D) cri du chat

Question 66

White sponge nevus is characterized by a white, corrugated, soft, folding oral mucosa always affecting _____ mucosa.

A) attached
B) lingual
C) buccal
D) tonsillar

Question 67

For parents who are carriers of the same recessive trait, the chance of giving birth to an affected child is _____%.

A) 0
B) 25
C) 50
D) 100

Question 68

Which term describes less than the normal amount of hair?

A) Hypoplastic
B) Hypotrichosis
C) Haploid
D) Nondisjunction

Question 69

_________ is a consistent feature of mandibulofacial dysostosis.

A) Hypertrichosis
B) Deafness
C) Hypertelorism
D) Kyphoscoliosis

Question 70

Blood group _____ is an example of gene codominance.

A) O
B) A
C) B
D) AB

Question 71

Self-replication, or the ability to duplicate itself, is achievable by

A) DNA.
B) amino acids.
C) meiosis.
D) genetic heterogeneity.

Question 72

Cases of facial clefting occur in about 1 in _____ births.

A) 80
B) 200
C) 800
D) 2000

Question 73

Oral manifestations seen with a person with Down syndrome include the following except one. Which is the exception?

A) Fissured tongue
B) Gingival and periodontal disease
C) Hypodontia
D) Macrodontia

Question 74

Ribonucleic acid (RNA) contains uracil rather than the base _____ found in DNA.

A) adenine
B) guanine
C) cytosine
D) thymine

Question 75

__________ 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

Question 76

A codon in DNA is formed by a sequence of _____ bases.

A) two
B) three
C) four
D) six

Question 77

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

Question 78

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

Question 79

Radicular dentin dysplasia is characterized by teeth with _____ crowns and _____ roots.

A) normal; normal
B) normal; abnormal
C) abnormal; normal
D) abnormal; abnormal

Question 80

The constriction present in all chromosomes that joins the short and long arms is termed

A) trisomy.
B) nondisjunction.
C) centromere.
D) translocation.