Download 41. Situations in which one allele for a gene is not

Genetics Test
Multiple Choice
Identify the choice that best completes the statement or answers the question.
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Situations in which one allele for a gene is not completely dominant over another allele for that gene are
called
a.
multiple genes.
c.
multiple alleles.
b.
polygenic inheritance.
d.
incomplete dominance.
The purpose of gene therapy is to
a.
cure genetic disorders.
b.
determine the sequences of genes.
c.
change dominant alleles to recessive alleles.
d.
remove mutations from genes.
If a man with a genotype IAi and a woman with the genotype IBi produce an offspring, what might be
the offspring’s blood type?
a.
A, B, AB, or O
c.
AB only
b.
AB or O
d.
A, B, or O
A tall plant is crossed with a short plant. If the tall F1 pea plants are allowed to self-pollinate,
a.
some of the offspring will be tall, and some will be short.
b.
all of the offspring will be tall.
c.
the offspring will be of medium height.
d.
all of the offspring will be short.
The failure of chromosomes to separate during meiosis is called
a.
nondisjunction.
c.
X-chromosome inactivation.
b.
Turner’s syndrome.
d.
Down syndrome.
What is the ultimate source of genetic variability?
a.
radiation
c.
mutations
b.
hybridization
d.
inbreeding
A DNA molecule produced by combining DNA from different sources is known as
a.
a mutant.
c.
a polyploid.
b.
recombinant DNA.
d.
a hybrid.
In humans, a male has
a.
two X chromosomes.
b.
one X chromosome only.
c.
one X chromosome and one Y chromosome.
d.
two Y chromosomes.
Which of the following genotypes result in the same phenotype (blood type)?
a.
IAIA and IAIB
c.
IBIB and IAIB
B
b.
I i and ii
d.
IBIB and IBi
Why is Dolly a clone?
a.
The DNA molecules in all her cells are identical.
b.
The source of her DNA was a single body cell.
c.
She was produced using the DNA from an adult’s egg cell.
d.
She is genetically identical to her offspring.
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Breeders induce mutations in organisms to
a.
avoid selective breeding.
b.
make organisms more alike.
c.
increase diversity in populations.
d.
produce organisms with undesirable characteristics.
Tt
T
t
T
TT
Tt
T
TT
Tt
TT
T =
t =
Tall
Short
Figure 11–1
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In the Punnett square shown in Figure 11–1, which of the following is true about the offspring
resulting from the cross?
a.
About half are expected to be tall.
c.
About half are expected to be short.
b.
All are expected to be tall.
d.
All are expected to be short.
What percentage of human sperm cells carry an X chromosome?
a.
50%
c.
25%
b.
0%
d.
100%
RrYy
RY
Ry
rY
ry
RY
RRYY
RRYy
RrYY
RrYy
Ry
RRYy
RRyy
RrYy
Rryy
RrYy
rY
RrYY
RrYy
rrYY
rrYy
ry
RrYy
Rryy
rrYy
rryy
Seed Shape
R = Round
r = Wrinkled
Seed Color
Y = Yellow
y = Green
Figure 11–2
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The Punnett square in Figure 11–2 shows that the gene for pea shape and the gene for pea color
a.
have the same alleles.
c.
are linked.
b.
assort independently.
d.
are always homozygous.
Which of the following are shown in a karyotype?
a.
homologous chromosomes
c.
sex chromosomes
b.
autosomes
d.
all of the above
Colorblindness is more common in males than in females because
a.
the allele for colorblindness is located on the Y chromosome.
b.
the allele for colorblindness is recessive and located on the X chromosome.
c.
fathers pass the allele for colorblindness to their sons only.
d.
males who are colorblind have two copies of the allele for colorblindness.
During transformation,
a.
foreign DNA is inserted into a plasmid.
b.
a cell is mutated.
c.
a cell takes in DNA from outside the cell.
d.
a prokaryote is changed into a eukaryote.
Gregor Mendel concluded that traits are
a.
inherited through the passing of factors from parents to offspring.
b.
not inherited by offspring.
c.
determined by dominant factors only.
d.
determined by recessive factors only.
Which of the following have been produced by selective breeding?
a.
dog breeds
c.
horse breeds
b.
cat breeds
d.
all of the above
Gregor Mendel used pea plants to study
a.
the inheritance of traits.
c.
gamete formation.
b.
cross-pollination.
d.
flowering.
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A human female inherits
a.
one copy of every gene located on the Y chromosome.
b.
two copies of every gene located on the X chromosome.
c.
twice as many sex chromosomes as a human male inherits.
d.
all of the same genes that a human male inherits.
How many chromosomes are shown in a normal human karyotype?
a.
23
c.
44
b.
2
d.
46
To make a new line of plants, Burbank used the process of
a.
inbreeding.
c.
hybridization.
b.
transformation.
d.
genetic engineering.
Human females produce egg cells that have
a.
one X and one Y chromosome.
c.
one X chromosome.
b.
two X chromosomes.
d.
one X or one Y chromosome.
What is the approximate probability that a human offspring will be female?
a.
10%
c.
25%
b.
50%
d.
75%
A pedigree can be used to
a.
determine whether a trait is inherited.
b.
determine whether an allele is dominant or recessive.
c.
show how a trait is passed from one generation to the next.
d.
all of the above
The crossing of buffalo and cattle to produce beefalo is an example of
a.
inbreeding.
c.
hybridization.
b.
genetic engineering.
d.
transformation.
Luther Burbank produced over 800 varieties of plants by
a.
selective breeding.
c.
DNA sequencing.
b.
genetic engineering.
d.
transformation.
When Gregor Mendel crossed true-breeding tall plants with true-breeding short plants, all the offspring
were tall because
a.
they were true-breeding like their parents.
b.
the allele for short plants is dominant.
c.
the allele for tall plants is recessive.
d.
the allele for tall plants is dominant.
What principle states that during gamete formation genes for different traits separate without
influencing each other’s inheritance?
a.
principle of dominance
c.
principle of probabilities
b.
principle of segregation
d.
principle of independent assortment
Figure 13–1
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In Figure 13–1, between which nucleotides is the DNA cut?
a.
adenine and thymine
c.
cytosine and guanine
b.
thymine and cytosine
d.
adenine and guanine
What does Figure 13–1 show?
a.
DNA sequencing
b.
polymerase chain reaction
c.
gel electrophoresis
d.
a restriction enzyme producing a DNA fragment
When Gregor Mendel crossed a tall plant with a short plant, the F1 plants inherited
a.
an allele for tallness from each parent.
b.
an allele for shortness from each parent.
c.
an allele from only the tall parent.
d.
an allele for tallness from the tall parent and an allele for shortness from the short
parent.
A cross of a black chicken (BB) with a white chicken (W W) produces all speckled offspring (BW).
This type of inheritance is known as
a.
codominance.
c.
multiple alleles.
b.
polygenic inheritance.
d.
incomplete dominance.
Which of the following statements is true?
a.
The mother of a colorblind boy must be colorblind.
b.
Females cannot have hemophilia.
c.
A sex-linked allele cannot be dominant.
d.
A colorblind boy received the allele for colorblindness from his mother.
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If you made a Punnett square showing Gregor Mendel’s cross between true-breeding tall plants and
true-breeding short plants, the square would show that the offspring had
a.
a genotype that was different from that of both parents.
b.
the genotype of one of the parents.
c.
the genotype of both parents.
d.
a phenotype that was different from that of both parents.
The Human Genome Project is an attempt to
a.
sequence all human DNA.
b.
identify alleles in human DNA that are recessive.
c.
cure human diseases.
d.
make a DNA fingerprint of every person’s DNA.
Organisms that have two identical alleles for a particular trait are said to be
a.
heterozygous.
c.
hybrid.
b.
dominant.
d.
homozygous.
What has been an advantage of producing transgenic plants?
a.
studying human genes
c.
increasing the food supply
b.
using more pesticides
d.
producing clones
One function of gel electrophoresis is to
a.
recombine DNA.
c.
extract DNA.
b.
separate DNA fragments.
d.
cut DNA.
Analyzing DNA by gel electrophoresis allows researchers to
a.
cut DNA with restriction enzymes.
b.
determine whether a particular allele of a gene is dominant or recessive.
c.
identify similarities and differences in the genomes of different kinds of organisms.
d.
compare the phenotypes of different organisms.
A Punnett square shows all of the following EXCEPT
a.
the genotypes of the offspring.
b.
all possible results of a genetic cross.
c.
the actual results of a genetic cross.
d.
the alleles in the gametes of each parent.
The principle of dominance states that
a.
all alleles are dominant.
b.
alleles are neither dominant nor recessive.
c.
all alleles are recessive.
d.
some alleles are dominant and others are recessive.
If a pea plant has a recessive allele for green peas, it will produce
a.
green peas if it does not also have a dominant allele for yellow peas.
b.
green peas if it also has a dominant allele for yellow peas.
c.
yellow peas if it does not also have a dominant allele for green peas.
d.
both green peas and yellow peas if it also has a dominant allele for yellow peas.
On an electrophoresis gel, band B is closer to the positive end of the gel than is band A. Which of the
following statements is true?
a.
Band A and band B contain the same DNA fragments.
b.
Band A moved faster than band B.
c.
The DNA fragments in band B were smaller than those in band A.
d.
The DNA in B is more positively charged than the DNA in A.
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A cat that has spots of more than one color
a.
is probably female.
c.
is probably male.
b.
has recessive alleles for coat color.
d.
has no Barr bodies.
Which of the following is most likely to bring together two recessive alleles for a genetic defect?
a.
inbreeding
c.
genetic engineering
b.
transformation
d.
hybridization
The principles of probability can be used to
a.
determine the actual outcomes of genetic crosses.
b.
predict the traits of the parents used in genetic crosses.
c.
predict the traits of the offspring produced by genetic crosses.
d.
decide which organisms are best to use in genetic crosses.
The process of DNA fingerprinting is based on the fact that
a.
no two people, except identical twins, have exactly the same DNA.
b.
the most important genes are different among most people.
c.
most people have DNA that contains repeats.
d.
most genes are dominant.
Most sex-linked genes are located on
a.
the Y chromosome only.
b.
the X chromosome only.
c.
the autosomes.
d.
both the X chromosome and the Y chromosome.
A heterozygous tall pea plant is crossed with a short plant. The probability that an F1 plant will be!tall is
a.
75%.
c.
25%.
b.
100%.
d.
50%.
Which of the following form(s) a Barr body?
a.
the X chromosome in a male cell
b.
the Y chromosome in a male cell
c.
one of the X chromosomes in a female cell
d.
both of the X chromosomes in a female cell
If nondisjunction occurs during meiosis,
a.
the chromatids do not separate.
b.
it occurs during prophase.
c.
only two gametes may form instead of four.
d.
some gametes may have an extra copy of some genes.
Which of the following can be observed in a karyotype?
a.
genes
c.
alleles
b.
a change in a DNA base
d.
an extra chromosome
The chemical factors that determine traits are called
a.
alleles.
c.
traits.
b.
genes.
d.
characters.
What kind of technique do scientists use to make transgenic organisms?
a.
inbreeding
c.
hybridization
b.
genetic engineering
d.
inducing of mutations
Offspring that result from crosses between parents with different traits
a.
are called hybrids.
c.
are true-breeding.
b.
make up the parental generation.
d.
make up the F2 generation.
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Which of the following includes all the others?
a.
selective breeding
c.
inbreeding
b.
hybridization
d.
induced mutations
The process of making changes in the DNA code of a living organism is called
a.
genetic engineering.
c.
inbreeding.
b.
hybridization.
d.
selective breeding.
If a pea plant that is heterozygous for round, yellow peas (RrYy) is crossed with a pea plant that is
homozygous for round peas but heterozygous for yellow peas (RRYy), how many different phenotypes
are their offspring expected to show? You may draw a punnett square to determine your answer.
a.
8
c.
16
b.
4
d.
2