NU 318 Genetics Exam 1 With
Complete Solution
Which of these complementary base pairs form the strongest or "tightest"
association?
A. Adenine and thymine
B. Cytosine and guanine
C. Guanine and thymine
D. Cytosine and Adenine - ANSWER B. Cytosine and guanine
-Cytosine and guanine have three sites for hydrogen bonds to form instead
of just two like adenosine and thymine have
How does the proteome differ from the genome?
A.The proteome changes in response to intracellular and extracellular signals.
B.The genome changes in response to intracellular and extracellular signals.
C.The proteome is stable in somatic cells and unstable in germ cells, whereas
the genome is stable in both somatic cells and germ cells.
D.The genome is stable in somatic cells and unstable in germ cells, whereas
the proteome is stable in both somatic cells and germ cells. - ANSWER A. The
proteome changes in response to intracellular and extracellular signals
The proteome is the protein content of any given cell. It is dynamic, changing
in response to intracellular and extracellular (environmental) signals.
,Therefore, the proteome is not an exact copy of the genome. The genome is
stable in all cells, and the proteome expresses different proteins (both
enzymes and structural proteins) at different times in different cells.
How does replacement of thymine with uracil in messenger RNA help in the
process of protein synthesis?
A.Allowing messenger RNA to leave the nucleus
B.Ensuring only the "sense" strand of DNA is transcribed
C.Determining the placement of the "start" signal for translation
D.Promoting post-translational modification for conversion to an active
protein - ANSWER A. Allowing RNA to leave the nucleus
RNA does not contain the pyrimidine base thymine. The base uracil is used in
place of thymine because it is a pyrimidine base with a structure that does
not contain the methyl group (CH3) that thymine has. This difference
between thymine and uracil is important because molecules in the nucleus
that contain a methyl group remain trapped inside the nucleus. Because the
remaining phases of protein synthesis occur outside the nucleus, the newly
transcribed RNA must be able to exit the nucleus.
How does the process of polyadenylation affect protein synthesis?
A.Binding to the antisense DNA strand to prevent inappropriate transcription
B.Promoting attachment of ribosomes to the correct end of messenger RNA
C.Linking the exons into the mature messenger RNA
D.Signaling the termination of mRNA translation - ANSWER D. Signaling the
termination of mRNA translation
,The addition of a poly-A tail to the newly transcripted RNA, known as
polyadenylation, results in a segment of RNA that contains mostly adenine
and is not translated into part of the protein. Thus, it serves as a signal to
stop translation.
What is the function of a suppressor gene product?
A.To ensure cell division occurs only when it is needed
B.To suppress the loss of differentiated functions with aging
C.To ensure the precise delivery of chromosomes to each new daughter cell
D.To prevent formation of a large nuclear-to-cytoplasmic ratio during the G0
state - ANSWER A. To ensure cell division occurs only when it is needed
Normal cells have their growth regulated by a balance between products
produced by oncogenes, which promote entering and completing the cell
cycle, with those of products produced by suppressor genes, which restrict or
inhibit entering and moving through the cell cycle. Thus, suppressor gene
products inhibit all aspects of mitosis and also trigger apoptosis. As a result,
cell division occurs only when it is needed and environmental conditions can
support more cells.
What is the expected result when two homologous chromosomes fail to
separate during meiosis I of spermatogenesis?
A.Fertilization of this gamete may result in a zygote that is 48, XXYY.
B.One gamete will have two of these chromosomes and one will have neither
of these chromosomes.
C.The risk for development of polygenic disorders is increased with
, fertilization of the polar body associated with this mature gamete.
D.Increased genetic diversity is possible with fertilization of any of these four
gametes because of an increased number of possible gene alleles. - ANSWER
B. One gamete will have two of these chromosomes and one will have neither
of these chromosomes
Failure of a chromosome to separate properly during meiosis is
nondisjunction. The result of nondisjunction is that one cell will have two
copies of the chromosome and the other cell will not have a copy of this
chromosome. Depending on which chromosome is missing or present in two
copies, viable embryos may be produced from fertilization, either as
monosomies or trisomies. This process does not result in a zygote with 48
chromosomes, nor will genetic diversity be increased. Polar bodies do not
form in spermatogenesis.
During which phase of gametogenesis is the process of crossing over more
likely to occur for either spermatocytes or oocytes?
A.Metaphase I
B.Interphase I
C.Anaphase I
D.Prophase I - ANSWER D. Prophase I
Crossing over is the lengthening and touching of the chromatids that allows
for pieces of sister chromatids to be exchanged. For both spermatogenesis
and oogenesis the process occurs during prophase I, although the timing
differs between the two processes.
Which statement regarding inheritance of an autosomal dominant gene allele
Complete Solution
Which of these complementary base pairs form the strongest or "tightest"
association?
A. Adenine and thymine
B. Cytosine and guanine
C. Guanine and thymine
D. Cytosine and Adenine - ANSWER B. Cytosine and guanine
-Cytosine and guanine have three sites for hydrogen bonds to form instead
of just two like adenosine and thymine have
How does the proteome differ from the genome?
A.The proteome changes in response to intracellular and extracellular signals.
B.The genome changes in response to intracellular and extracellular signals.
C.The proteome is stable in somatic cells and unstable in germ cells, whereas
the genome is stable in both somatic cells and germ cells.
D.The genome is stable in somatic cells and unstable in germ cells, whereas
the proteome is stable in both somatic cells and germ cells. - ANSWER A. The
proteome changes in response to intracellular and extracellular signals
The proteome is the protein content of any given cell. It is dynamic, changing
in response to intracellular and extracellular (environmental) signals.
,Therefore, the proteome is not an exact copy of the genome. The genome is
stable in all cells, and the proteome expresses different proteins (both
enzymes and structural proteins) at different times in different cells.
How does replacement of thymine with uracil in messenger RNA help in the
process of protein synthesis?
A.Allowing messenger RNA to leave the nucleus
B.Ensuring only the "sense" strand of DNA is transcribed
C.Determining the placement of the "start" signal for translation
D.Promoting post-translational modification for conversion to an active
protein - ANSWER A. Allowing RNA to leave the nucleus
RNA does not contain the pyrimidine base thymine. The base uracil is used in
place of thymine because it is a pyrimidine base with a structure that does
not contain the methyl group (CH3) that thymine has. This difference
between thymine and uracil is important because molecules in the nucleus
that contain a methyl group remain trapped inside the nucleus. Because the
remaining phases of protein synthesis occur outside the nucleus, the newly
transcribed RNA must be able to exit the nucleus.
How does the process of polyadenylation affect protein synthesis?
A.Binding to the antisense DNA strand to prevent inappropriate transcription
B.Promoting attachment of ribosomes to the correct end of messenger RNA
C.Linking the exons into the mature messenger RNA
D.Signaling the termination of mRNA translation - ANSWER D. Signaling the
termination of mRNA translation
,The addition of a poly-A tail to the newly transcripted RNA, known as
polyadenylation, results in a segment of RNA that contains mostly adenine
and is not translated into part of the protein. Thus, it serves as a signal to
stop translation.
What is the function of a suppressor gene product?
A.To ensure cell division occurs only when it is needed
B.To suppress the loss of differentiated functions with aging
C.To ensure the precise delivery of chromosomes to each new daughter cell
D.To prevent formation of a large nuclear-to-cytoplasmic ratio during the G0
state - ANSWER A. To ensure cell division occurs only when it is needed
Normal cells have their growth regulated by a balance between products
produced by oncogenes, which promote entering and completing the cell
cycle, with those of products produced by suppressor genes, which restrict or
inhibit entering and moving through the cell cycle. Thus, suppressor gene
products inhibit all aspects of mitosis and also trigger apoptosis. As a result,
cell division occurs only when it is needed and environmental conditions can
support more cells.
What is the expected result when two homologous chromosomes fail to
separate during meiosis I of spermatogenesis?
A.Fertilization of this gamete may result in a zygote that is 48, XXYY.
B.One gamete will have two of these chromosomes and one will have neither
of these chromosomes.
C.The risk for development of polygenic disorders is increased with
, fertilization of the polar body associated with this mature gamete.
D.Increased genetic diversity is possible with fertilization of any of these four
gametes because of an increased number of possible gene alleles. - ANSWER
B. One gamete will have two of these chromosomes and one will have neither
of these chromosomes
Failure of a chromosome to separate properly during meiosis is
nondisjunction. The result of nondisjunction is that one cell will have two
copies of the chromosome and the other cell will not have a copy of this
chromosome. Depending on which chromosome is missing or present in two
copies, viable embryos may be produced from fertilization, either as
monosomies or trisomies. This process does not result in a zygote with 48
chromosomes, nor will genetic diversity be increased. Polar bodies do not
form in spermatogenesis.
During which phase of gametogenesis is the process of crossing over more
likely to occur for either spermatocytes or oocytes?
A.Metaphase I
B.Interphase I
C.Anaphase I
D.Prophase I - ANSWER D. Prophase I
Crossing over is the lengthening and touching of the chromatids that allows
for pieces of sister chromatids to be exchanged. For both spermatogenesis
and oogenesis the process occurs during prophase I, although the timing
differs between the two processes.
Which statement regarding inheritance of an autosomal dominant gene allele
