BIL 150 Exam 3 || A+ GRADED SOLUTIONS.
Which of the following statements is true of a species that has a chromosome number of
2n=16? correct answers Each diploid cell has 8 homologous pairs of chromosomes
Many diploid organisms produce haploid gametes for reproduction. Which of the following
best describes how the diploid number of chromosomes is restored in the offspring of these
organisms? correct answers fertilization combines chromosomes from each parent into
resulting zygote
A cell has completed meiosis I and the first cytokinesis, and is just beginning meiosis II.
Which of the following describes its genetic contents? correct answers It has half the amount
of DNA as the cell that began meiosis
Which of the following describes a major difference between mitosis and meiosis I in a
diploid organism? correct answers sister chromatids separate in mitosis, while homologous
pairs of chromosomes separate in meiosis I
Independent assortment of chromosomes is a result of which process? correct answers the
random way each pair of homologous chromosomes lines up at the metaphase plate during
meiosis I
Which of the following results when homologous chromosomes cross over in meiosis?
correct answers corresponding segments of non-sister chromatids are exchanged
Two different species of protists live in a tide pool. Species A reproduces both sexually and
asexually, and Species B reproduce only asexually. The pool gradually becomes infested with
disease-causing viruses. Which species are more likely to survive in the changing correct
answers species A only
Which of the following states a significant conclusion that Gregor Mendel drew from his
experiments with pea plants? correct answers Traits are inherited in discrete units and are not
the result of "blending"
Which statement correctly describes how Mendel explained why traits disappeared in the F1
generation and then reappeared in the F2 generation? correct answers traits can be dominant
or recessive, and the recessive traits were "hidden" by the dominant ones in F1
Mendel crossed true breeding yellow-seeded and green-seeded pea plants and then allowed
the offspring to self pollinate to produce an F2 generation. The results were: 6022 yellow and
2001 green (8,023 total). Which statement correctly describes the relationship of the allele for
green seeds to the allele for yellow seeds? correct answers The green allele is recessive to the
yellow allele
Albinism is a recessive trait where an individual does not produce the pigment melanin. A
man and woman who both produce melanin have one child out of three who has albinism.
What are the genotypes of the man and woman? correct answers Both parents must be
heterozygous
, Black fur in mice (B) is dominant to brown fur (b). Short tails (S) are dominant to long tails
(s). What fraction of the progeny of crosses BbSs × BBss will be expected to have black fur
and long tails? correct answers 1/2
In a cross of individuals who both possess the genotype AaBbCc, what proportion of the
offspring is predicted to have the genotype AABBCC? correct answers 1/64
Phenylketonuria is an inherited disease caused by a recessive allele. If a woman and her
husband are both carriers, what is the probability that their first child will be a girl without the
disease? correct answers 3/8
Which of the following phenotypes is an example of polygenic inheritance? correct answers
skin pigmentation in humans
Marfan syndrome in humans is caused by an abnormality of the connective tissue protein
fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the
spine, sometimes weakened arterial walls, and sometimes ocular problems, such as lens
dislocation. Which of the following would you conclude about Marfan syndrome from this
information? correct answers it is pleiotropic
Which of the following best describes the chromosome theory of inheritance as it was
understood in the early 20th century? correct answers mendelian genes are its specific loci on
the chromosome and, in turn, segregate during meiosis
Males are more often affected by x-linked traits than females because correct answers males
are hemizygous genes on the X chromosomes
Red-green color blindness is an x-linked recessive trait in humans. Two people with normal
color vision have a color-blind son. What are the genotypes of the parents? correct answers
xNxn and xNy
Male sex determination in mammals is in large part due to the SRY gene found on the Y
chromosome. Which of the following scenarios will result in a person with an XX karyotype
developing a male phenotype? correct answers translocation of SRY to an X chromosome
during gamete formation
Glucose-6-phosphate dehydrogenase deficiency is inherited as an X-linked recessive allele in
humans. A woman whose father had G6PD is planning a family with a man who has no
history of the disease. What proportion of their sons are expected to have the disease? correct
answers 1/2
A couple has a child with Down syndrome. Which of the following is the most probable
cause of the child's condition?A) the woman's genome has a chromosomal duplication correct
answers One member of the couple underwent nondisjunction during meiosis
A sample of double-stranded DNA contains 28% thymine. Approximately what percent of
the nucleotides in this sample will be guanine? correct answers 22%
Which of the following statements is true of a species that has a chromosome number of
2n=16? correct answers Each diploid cell has 8 homologous pairs of chromosomes
Many diploid organisms produce haploid gametes for reproduction. Which of the following
best describes how the diploid number of chromosomes is restored in the offspring of these
organisms? correct answers fertilization combines chromosomes from each parent into
resulting zygote
A cell has completed meiosis I and the first cytokinesis, and is just beginning meiosis II.
Which of the following describes its genetic contents? correct answers It has half the amount
of DNA as the cell that began meiosis
Which of the following describes a major difference between mitosis and meiosis I in a
diploid organism? correct answers sister chromatids separate in mitosis, while homologous
pairs of chromosomes separate in meiosis I
Independent assortment of chromosomes is a result of which process? correct answers the
random way each pair of homologous chromosomes lines up at the metaphase plate during
meiosis I
Which of the following results when homologous chromosomes cross over in meiosis?
correct answers corresponding segments of non-sister chromatids are exchanged
Two different species of protists live in a tide pool. Species A reproduces both sexually and
asexually, and Species B reproduce only asexually. The pool gradually becomes infested with
disease-causing viruses. Which species are more likely to survive in the changing correct
answers species A only
Which of the following states a significant conclusion that Gregor Mendel drew from his
experiments with pea plants? correct answers Traits are inherited in discrete units and are not
the result of "blending"
Which statement correctly describes how Mendel explained why traits disappeared in the F1
generation and then reappeared in the F2 generation? correct answers traits can be dominant
or recessive, and the recessive traits were "hidden" by the dominant ones in F1
Mendel crossed true breeding yellow-seeded and green-seeded pea plants and then allowed
the offspring to self pollinate to produce an F2 generation. The results were: 6022 yellow and
2001 green (8,023 total). Which statement correctly describes the relationship of the allele for
green seeds to the allele for yellow seeds? correct answers The green allele is recessive to the
yellow allele
Albinism is a recessive trait where an individual does not produce the pigment melanin. A
man and woman who both produce melanin have one child out of three who has albinism.
What are the genotypes of the man and woman? correct answers Both parents must be
heterozygous
, Black fur in mice (B) is dominant to brown fur (b). Short tails (S) are dominant to long tails
(s). What fraction of the progeny of crosses BbSs × BBss will be expected to have black fur
and long tails? correct answers 1/2
In a cross of individuals who both possess the genotype AaBbCc, what proportion of the
offspring is predicted to have the genotype AABBCC? correct answers 1/64
Phenylketonuria is an inherited disease caused by a recessive allele. If a woman and her
husband are both carriers, what is the probability that their first child will be a girl without the
disease? correct answers 3/8
Which of the following phenotypes is an example of polygenic inheritance? correct answers
skin pigmentation in humans
Marfan syndrome in humans is caused by an abnormality of the connective tissue protein
fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the
spine, sometimes weakened arterial walls, and sometimes ocular problems, such as lens
dislocation. Which of the following would you conclude about Marfan syndrome from this
information? correct answers it is pleiotropic
Which of the following best describes the chromosome theory of inheritance as it was
understood in the early 20th century? correct answers mendelian genes are its specific loci on
the chromosome and, in turn, segregate during meiosis
Males are more often affected by x-linked traits than females because correct answers males
are hemizygous genes on the X chromosomes
Red-green color blindness is an x-linked recessive trait in humans. Two people with normal
color vision have a color-blind son. What are the genotypes of the parents? correct answers
xNxn and xNy
Male sex determination in mammals is in large part due to the SRY gene found on the Y
chromosome. Which of the following scenarios will result in a person with an XX karyotype
developing a male phenotype? correct answers translocation of SRY to an X chromosome
during gamete formation
Glucose-6-phosphate dehydrogenase deficiency is inherited as an X-linked recessive allele in
humans. A woman whose father had G6PD is planning a family with a man who has no
history of the disease. What proportion of their sons are expected to have the disease? correct
answers 1/2
A couple has a child with Down syndrome. Which of the following is the most probable
cause of the child's condition?A) the woman's genome has a chromosomal duplication correct
answers One member of the couple underwent nondisjunction during meiosis
A sample of double-stranded DNA contains 28% thymine. Approximately what percent of
the nucleotides in this sample will be guanine? correct answers 22%
