BIL 150 EXAM 3|| 54 QUESTIONS AND
ANSWERS 100% ACCURATE
Which of the following statements is true of a species that has a chromosome number
of 2n=16? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-sister chromatids separate in mitosis, while homologous
pairs of chromosomes separate in meiosis I
Independent assortment of chromosomes is a result of which process? - ANSWER-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? -
ANSWER-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 - ANSWER-species A only
Which of the following phenotypes is an example of polygenic inheritance? - ANSWER-
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? - ANSWER-it is pleiotropic
Which of the following best describes the chromosome theory of inheritance as it was
understood in the early 20th century? - ANSWER-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 - ANSWER-
males are hemizygous genes on the X chromosomes
Which of the following states a significant conclusion that Gregor Mendel drew from his
experiments with pea plants? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-3/8
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? -
ANSWER-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? - ANSWER-translocation of SRY to an X
chromosome during gamete formation
ANSWERS 100% ACCURATE
Which of the following statements is true of a species that has a chromosome number
of 2n=16? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-sister chromatids separate in mitosis, while homologous
pairs of chromosomes separate in meiosis I
Independent assortment of chromosomes is a result of which process? - ANSWER-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? -
ANSWER-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 - ANSWER-species A only
Which of the following phenotypes is an example of polygenic inheritance? - ANSWER-
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? - ANSWER-it is pleiotropic
Which of the following best describes the chromosome theory of inheritance as it was
understood in the early 20th century? - ANSWER-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 - ANSWER-
males are hemizygous genes on the X chromosomes
Which of the following states a significant conclusion that Gregor Mendel drew from his
experiments with pea plants? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-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? - ANSWER-3/8
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? -
ANSWER-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? - ANSWER-translocation of SRY to an X
chromosome during gamete formation
