Transcript Animal breeders use test crosses to determine whether an

Animal breeders use test crosses to
determine whether an individual animal
________.
1.
2.
is fertile
is homozygous dominant or
heterozygous
is homozygous recessive or
heterozygous
is phenotypically dominant or
recessive
was the product of
segregation or independent
assortment
3.
4.
5.
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Blood typing is often used to resolve questions of
paternity; could a man with blood type A father a
child with blood type B?
1.
no, only males with type B or AB
have children with type B blood
yes, if his genotype was IAIi and
the mother had B or AB blood
yes, independent assortment
recombines all possible bloodgroup genes during gamete
formation
no, children always have the
same blood type as their fathers
yes, blood type is the result of
environmental influences, not
inheritance
2.
3.
4.
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Assuming the species to be diploid, the
notation Ab would be used to represent
________.
1.
a gamete from a dihybrid
cross
an individual from the F1
generation
a heterozygous parent
an individual displaying both
dominant phenotypes
this notation would never be
encountered
2.
3.
4.
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When tall peas are crossed with dwarf peas,
the resulting seeds all grow into tall plants,
indicating that ________.
1.
tall plants survive better in
the natural environment
tall is the dominant form for
the alleles controlling height
plant height is strongly
influenced by environmental
factors
plant height in peas is a
polygenic trait
pleiotropy can be observed in
both plants and animals
2.
3.
4.
5.
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The first three children of a couple, both heterozygous for
cystic fibrosis, were healthy; what is the probability that a
fourth child will have the disease?
1.
2.
3.
4.
5.
1
100%
75%
50%
25%
it is impossible to
predict
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The 9:3:3:1 ratio reported by Mendel during
dihybrid crosses suggested that ________.
1.
dominant alleles are superior to
recessive alleles and appear
more frequently in offspring
the sorting of any pair of
homologous chromosomes is
independent of the sorting of
any other pair
either homozygous genotype is
preferable to the heterozygous
phenotype
mutation rates are unusually
high in pea plants
segregation applied only to
monohybrid crosses
2.
3.
4.
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Which example illustrates
pleiotropy?
1.
human ear lobes may be attached or
free
crosses between red and white
snapdragons produce pink
snapdragons
individuals homozygous for the
cystic fibrosis allele suffer numerous
physiological problems
humans have one of the four blood
types within the ABO system
when tall, purple peas are crossed
with short, white peas, some
offspring may be tall and white
2.
3.
4.
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What conclusions can be made of a five-fingered
child born to polydactylous parents, a dominant
trait characterized by extra fingers?
1.
a mutation reversed the allele to
its normal state in either of the
parent's gametes
polydactyly must not be a
genetic condition
the parents were both
heterozygous for the condition
the environmental factors
favoring the development of
polydactyly were absent for the
child
polydactyly must result from an
epistatic interaction
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3.
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If an ABO blood typing reveals that you are
homozygous recessive (IiIi), your blood type
________.
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20%
1. could be either A
or B
2. must be O
3. must be A
4. must be B
5. must be AB
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Offspring of a cross between true-breeding
lineages that inherit nonidentical alleles are
called ________.
20% 20% 20% 20%
20%
1. hybrids
2. recessives
3. mutants
4. codominants
5. recombinants
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When crossing a homozygous-dominant
parent with a homozygous-recessive parent,
the offspring will ________.
1.
produce a 1:2:1 genotype ratio
and a 3:1 phenotype ratio
produce a 1:1 genotype ratio
and a 1:1 phenotype ratio
produce a 3:1 genotype ratio
and a 3:1 phenotype ratio
produce a 3:1 genotype ratio
and a 1:2:1 phenotype ratio
all be the same, both
genotypically and phenotypically
2.
3.
4.
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Several molecular forms of the same gene
may exist; collectively these forms are
termed ________.
20% 20% 20% 20%
20%
1. alleles
2. homologous
genes
3. loci
4. mutations
5. heterogeneous
genes
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In a genetics experiment, the offspring
produced when parents are crossed are
called ________.
1. the F1 generation 20% 20% 20% 20% 20%
2. the F2 generation
3. the P2 generation
4. the heterozygotes
5. none of the
choices is correct
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With the exception of identical twins,
brothers and sisters of the same parents are
notably different because ________.
1.
2.
3.
4.
5.
1
independent assortment
recombines genetic material in
new ways during gamete
formation
crossing over recombines
genetic material in new ways
during gamete formation
each pair of chromosomes
[MKC1] segregates during
gamete formation
many features require several
pairs of genes that may not be
closely linked
all of the choices are correct
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Two genes are closely linked
when ________.
1.
the combination of features
increases the fitness above
that of either trait separately
the distance between their
loci is small
they are located on
homologous chromosomes
their recombination
frequencies are high
all of the choices are correct
2.
3.
4.
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The genes for ABO blood typing are IA, IB,
and Ii; the superscripts indicate that
________.
1.
three separate loci are
associated with this trait
the genes are
incompletely dominant
the genes for blood typing
form a linkage group
the locus has multiple
alleles
ABO blood typing results
from epistatic interactions
2.
3.
4.
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The coat color in Labrador retrievers is the
result of epistasis, an interaction ________.
1.
between the skin temperature
and the activity of the enzymes
producing fur pigmentation
between an allosteric inhibitor
and the enzymes responsible for
fur coloration
when an individual allele has
more than one effect on the
phenotype
between the dominant and
recessive alleles
where two pairs of genes
interact to produce the
phenotype
2.
3.
4.
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If a plant that breeds true for the dominant version of a trait
is crossed with one that breeds true for the recessive
version of that trait, they will produce ________.
1.
homozygous and heterozygous
offspring in equal proportions
offspring that are homozygous
for the dominant version of the
trait
offspring that are homozygous
for the recessive version of that
trait
offspring that are heterozygous
for the trait
a random and unpredictable mix
of both phenotypes
2.
3.
4.
5.
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When yarrow cuttings are planted at
different elevations, the plants show different
forms because:
1.
in yarrow, phenotype is
influenced by the environment
a plant's genotype can change
during its lifetime
the cuttings were not genetically
identical
soil variations exist at different
elevations
higher altitudes experience more
intense radiation and thus higher
rates of mutation
2.
3.
4.
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Geneticists are using marker-assisted
selection in their efforts to breed roses; in
this technique, ________.
1.
DNA probes are used to determine if
an offspring plant has inherited a
specific gene
the mature flower of an offspring
plant fluoresces when illuminated
with ultraviolet light
rose pollen is exposed to radiation
before pollination
the seeds from experimental
crosses are planted, grown to
maturity, and then evaluated for
markers such as fragrance
stamens are cut so that selfpollination is not possible
2.
3.
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