Klinefelter's syndrome is caused by a nondisjunction resulting in a genotype ofA)YYYB)XYYC)XXXD)XXY

D

In the F₂ generation, the 3:1 ratio is really a disguised
A)1:2:1
B)2:1:1
C)1:1:2
D)4:0
E)4:1

A

The ratio often referred to the Mendelian ratio is
A)1:3:3:1
B)9:7
C)1:3:1
D)1:1
E)3:1

E

When Mendel crossed pure-breeding purple and white flowered pea plants, the dominant to recessive ratio in the F₁ generation was
A)3:1
B)4:0
C)4:1
D)4:0
E)9:3:3:1

B

On which of the following chromosomes are sex-linked traits carried?

A)13
B)18
C)Y
D)15
E)X

E

The genotype of an individual with Turner syndrome is
A)YO
B)XXY
C)XYY
D)XO
E)XXX

D

In Mendel's F₂ generation of the purple and white flower crossing, the dominant to recessive ratio was
A)1:3:1
B)3:1
C)1:1
D)9:7
E)9:3:3:1

B

The name for a chromosome map unit is
A)centimorgan
B)centistern
C)millimendel
D)decibarr
E)centisutton

A

Which of the following represents a testcross?

A)Ww x WW
B)ww x WW
C)Ww x Ww
D)WW x WW

B

A disease caused by an autosomal primary nondisjunction is

A)Turner syndrome
B)Down syndrome
C)Tay-Sachs disease
D)Klinefelter syndrome
E)PKU

B

A individual who has two of the same allele is said to be
A)homozygous
B)heteromologous
C)homologous
D)heterozygous
E)diplozygous

A

Which of the following represents a dihybrid?
A)WWSs
B)WwSS
C)WwSs
D)WWss
E)wwSs

C

Where two alternatives for a trait are tall and short, and tall is dominant, the genotype of a heterozygous individual would be expressed
A)sS
B)ss
C)SS
D)Ss
E)tall

D

Which of the following chromosomes, if trisomic, cause failure of survival of development?
A)X
B)21
C)11
D)18
E)15

C

The appearance resulting from a given gene combination is referred to as the
A)genotype
B)phenotype
C)phototype
D)alleleotype
E)stereotype

B

Compared to previous geneticists, the unique characteristic of Mendel's work was
A)keeping records of numbers of different progeny
B)choosing the garden pea for his experiment
C)producing hybrids
D)studying more than one generation
E)crossing true-breeding plants

A

A modified Mendelian ratio is represented by
A)9:3:3:1
B)1:3:1
C)3:1
D)9:7
E)1:1

D

The two alternatives for a trait are red and white and red is dominant. However, white is the most common trait. What is the genotype of a homozygous dominant individual?
A)RR
B)rr
C)WW
D)ww
E)red

C

Where the two alternatives for a trait are broad and narrow, and broad is dominant, the phenotype of a homozygous dominant individual would be expressed as
A)BB
B)nn
C)Bn
D)NN
E)broad

E

A genetic disorder caused by a dominant allele is
A)sickle-cell anemia
B)PKU
C)Tay-Sachs disease
D)hemophilia (royal)
E)Huntington's disease

D

Early ideas about heredity includeA)traits can be masked in some generationsB)traits were segregated among progenyC)alleles do not influence each otherD)traits are transmitted directlyE)not all copies of a factor are identical

D

What is the phenotype of a fruit fly whose genotype is g⁺g⁺vsvs (where g = gray body and vs = vestigial wings; wild type = black body and normal wings)?

A)gray body; vestigial wings
B)gray body; normal wings
C)black body; vestigial wings
D)black body; normal wings

C

In garden peas, height is determined by a single gene with tall being dominate to short. If two heterozygous plants are crossed, what proportion of the tall progeny will be homozygous dominant?
A)3/4
B)2/3
C)1/2
D)1/3
E)1/4

D

In the cross MMnn x mmNN, what proportion of the resulting F₁ would be homozygous dominant for both genes?
A)none
B)1/16
C)3/16
D)9/16
E)all

A

In humans pointed eyebrows are dominant to smooth eyebrows and widow's peak (downward pointed frontal hairline) is dominant to continuous hairline. What phenotypic ratio would you expect in the offspring from a cross between an individual heterozygous for both genes and an individual homozygous recessive for both genes?
A)9:3:3:1
B)9:3:4
C)1:1:1:1
D)1:2:1:2:4:2:1:2:1
E)9:7

C

Hypertrichosis, hairiness of the pinna of the ear, is inherited as a Y-linked recessive in humans. If a man with hypertrichosis marries a normal woman, what types of children may they have?
A)All of their children of both sexes have hypertrichosis.
B)All the sons have hypertrichosis, but none of their daughters.
C)Half of their sons, but none of their daughters will have hypertrichosis.
D)All the daughters have hypertrichosis, but none of their sons.
E)None of their children have hypertrichosis.

B

The model for the dihybrid cross of heterozygotes predicts a phenotypic ratio of 9:3:3:1.
A)True
B)False

TRUE

Epistasis is a genetic condition in which certain alleles of one locus can alter the expression of alleles of a different locus.
A)True
B)False

TRUE

One gene can have multiple effects on an organism.

A)True
B)False

TRUE

The genotypes of a husband and wife are I^AI^B x I^Ai. Among the blood types of their children, how many different genotypes and phenotypes are possible?
A)2 genotypes; 3 phenotypes
B)3 genotypes; 4 phenotypes
C)4 genotypes; 4 phenotypes
D)3 genotypes; 3 phenotypes
E)4 genotypes; 3 phenotypes

E

A trait caused by a recessive autosomal allele will result in a pedigree that shows affected individuals having at least one affected parent.

A)True
B)False

FALSE

Down syndrome results from:
A)the absence of one chromosome in position 21
B)the presence of an extra chromosome in position 21
C)the absence of both chromosomes in position 21
D)crossing over on the chromosomes in position 21
E)none of the above

B

Which of the following is not a result of nondisjunction of the sex chromosomes?
A)Down syndrome
B)Barr body
C)Turner syndrome
D)Klinefelter syndrome
E)both a and b

E