Chapter 4

Question 1

which genetic disease is caused by an abnormal karyotype

a. down syndrome
b. huntington disease
c. phenylketonuria
d. neurofibromatosis

Answer 1

Down syndrome

Question 2

Down syndrome usually occurs because of

a. an abnormal x chromosome
b. nondisjunction by older ova
c. an autosomal dominant gene
d. an autosomal recessive gene

Answer 2

nondisjunction by older ova

Question 3

Cri-du-chat syndrome is an abnormality of chromosomal structure that involves

a. translocation
b. an inversion
c. duplication
d. deletion

Answer 3

deletion

Question 4

Fragile X syndrome can affect intelligence and behavior in

a. males only
b. females only
c. both males and females
d. neither because affected fetuses are aborted

Answer 4

both males and females

Question 5

If homologous chromosomes fail to separate during meiosis, the disorder is

a. polyploidy
b. aneuploidy
c. disjunction
d. nondisjunction

Answer 5

nondisjunction

Question 6

cystic fibrosis has been mapped to chromosome

a. 17
b. 7
c. X
d. 16

Answer 6

7

Question 7

In autosomal dominant inherited disorders

a. affected individuals do not have an affected parent
b. affected individuals who mate with unaffected people have a 50% risk of having an affected offspring
c. male offspring are most often affected
d. unaffected children born to affected parents will have affected children

Answer 7

b. affected individuals who mate with unaffected people have a 50% risk of having an affected off spring

Question 8

in x linked recessive inherited disorders

a. affected males have normal sons
b. affected males have affected daughters
c. sons of female carriers have a 50% risk of being affected
d. the affected male transmits the gene to all daughters thus they are carriers

Answer 8

affected males have normal sons
affected males have normal daughters
the affected male transmits the gene to all daughters, thus they are carriers.

Question 9

duchenne muscular dystrophy is

a. a sex linked genetic disease wherein dystrophin is not encoded
b. an autosomal recessive disease
c. an autosomal dominant disease
d. mapped to chromosome 17

Answer 9

a sex linked genetic disease wherein dystrophin is not encoded.

Question 10

if a male inherits an autosomal recessive disorder he inherited it from his

a. mother
b. father
c. mother & father

Answer 10

mother and father

Question 11

Trisomy 21 syndrome is caused by

a. paternal disjunction
b. maternal disjunction
c. maternal translocation

Answer 11

maternal nondisjunction

Question 12

recessive disorder

a. due to numerical or structural aberrations
b. individual homozygous for a gene
c. outward appearance of an individual

Answer 12

individual homozygous for a gene

Question 13

genotype

a. expresses genes
b. outward appearance of an individual
c. gene combination

Answer 13

gene combination

Question 14

aneuploidy

a. a cell with fewer or more chromosomes than normal
b. failure of homologous chromosomes to separate during meiosis or mitosis
c. individual homozygous for a gene

Answer 14

a cell with fewer or more chromosomes than normal

Question 15

chromosomal aberration

a. due to numerical or structural aberration
b. outward appearance of an individual
c. gene combination

Answer 15

due to numerical or structural aberration

Question 16

phenotype:

a. expresses genes
b. gene combination
c. outward appearance of an individual

Answer 16

outward appearance of an individual

Question 17

pedigree

a. a probability of 0.25
b. expresses genes
c. a cell with fewer or more chromosomes than normal

Answer 17

expresses genes

Question 18

autosomal recessive inheritance

a. a probability of 0.25
b. extent of phenotypic variation of a particular genotype
c. females unlikely to be affected

Answer 18

a probability of 0.25

Question 19

expressivity

a. females unlikely to be affected
b. one allele permits expression
c. extent of phenotypic variation of a particular genotype

Answer 19

extent of phenotypic variation of a particular genotype

Question 20

x linked

a. one allele permits expression
b. females unlikely to be affected
c. no loss or gain of genetic material

Answer 20

females unlikely to be affected

Question 21

inversion

a. a probability of 0.25
b. expresses genes
c. no loss or gain of genetic material

Answer 21

no loss or gain of genetic material

Question 22

dominant trait

a. different version of the same paired gene
b. klinefelter syndrome
c. one allele permits expression

Answer 22

one allele permits expression

Question 23

allele

a. different version of the same paired gene
b. pedigree
c. phenotype

Answer 23

different version of the same paired gene

Question 24

47 XXY

a. down syndrome
b. klinefelter syndrome

Answer 24

klinefelter syndrome

Question 25

Karyotype

a. species chromosomal morphology
b. no loss or gain of genetic material
c. extent of phenotypic variation of a particular genotype

Answer 25

species chromosomal morphology