MMSC491 Exam 2 Study Guide
Questions and Answers 100% Pass
The term phenotype can be applied to a wide range of manifestations.
Which of the following properties, if any, do not constitute a phenotypic
manifestation?
The number of digits a person has.
The transcriptome of a single T cell.
The sequence of a persons beta globin gene.
autistic behavior - ANSWER✔✔-The sequence of a persons beta globin
gene.
Which, if any, of the following is incorrect? When used in human genetics,
the terms dominant and recessive apply equally to alleles and phenotypes.
dominant describes a phenotype that is manifested in the heterozygote,
that is, the phenotype is attributable to just a single allele.
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,recessive describes a phenotype that is manifest as a result of the combined
effects of both alleles at a locus.
the AB blood group is an example of a co-dominant phenotype. -
ANSWER✔✔-the terms dominant and recessive apply equally to alleles
and phenotypes.
With respect to autosomal recessive inheritance, which, if any, of the
following statements is incorrect?
Affected individuals normally have unaffected parents.
For unaffected parents who have a previously affected child, there is a 1 in
4 risk of having an affected child on each occasion that they produce a new
child.
Heterozygotes are always asymptomatic carriers.
Some affected individuals have alleles with identical pathogenic mutations
but many have two different mutant alleles and are described as
compound heterozygotes. - ANSWER✔✔-Heterozygotes are always
asymptomatic carriers.
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,With respect to X-chromosome inactivation in females, which, if any, of the
following statements is incorrect?
X-inactivation first occurs in the preimplantation female mammalian
embryo.
One of the two X chromosomes in each diploid cell of a normal woman is
randomly selected to undergo X-inactivation and becomes highly
condensed.
The process involves epigenetic silencing of each gene on one of the two X
chromosomes, either the maternal X chromosome or the paternal X
chromosome.
Once the decision is made to inactivate a paternal X or the maternal X in a
cell, all descendant cells will continue with that pattern of X-inactivation. -
ANSWER✔✔-The process involves epigenetic silencing of each gene on
one of the two X chromosomes, either the maternal X chromosome or the
paternal X chromosome.
With respect to X-linked recessive inheritance, which, if any, of the
following statements is false?
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, Males with just one mutant allele are affected because, lacking a second X
chromosome, they do not have a normal allele.
Women are always asymptomatic.
The disorder is not transmitted from fathers to sons.
Each child born to a normal man and a carrier woman has a risk of 1in 4 of
being affected. - ANSWER✔✔-Women are always asymptomatic.
With respect to X-linked dominant inheritance, which, if any, of the
following statements is false?
There are significantly more affected females than males.
Each child born to an affected mother has a risk of 1 in 2 of being affected.
Each daughter born to an affected father has a risk of 1 in 2 of being
affected.
Each boy born to an affected father has a negligible risk of being affected. -
ANSWER✔✔-Each daughter born to an affected father has a risk of 1 in 2
of being affected.
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Questions and Answers 100% Pass
The term phenotype can be applied to a wide range of manifestations.
Which of the following properties, if any, do not constitute a phenotypic
manifestation?
The number of digits a person has.
The transcriptome of a single T cell.
The sequence of a persons beta globin gene.
autistic behavior - ANSWER✔✔-The sequence of a persons beta globin
gene.
Which, if any, of the following is incorrect? When used in human genetics,
the terms dominant and recessive apply equally to alleles and phenotypes.
dominant describes a phenotype that is manifested in the heterozygote,
that is, the phenotype is attributable to just a single allele.
Copyright ©EMILLYCHARLOTE 2025 ACADEMIC YEAR, ALL RIGHTS RESERVED. Page 1/47
,recessive describes a phenotype that is manifest as a result of the combined
effects of both alleles at a locus.
the AB blood group is an example of a co-dominant phenotype. -
ANSWER✔✔-the terms dominant and recessive apply equally to alleles
and phenotypes.
With respect to autosomal recessive inheritance, which, if any, of the
following statements is incorrect?
Affected individuals normally have unaffected parents.
For unaffected parents who have a previously affected child, there is a 1 in
4 risk of having an affected child on each occasion that they produce a new
child.
Heterozygotes are always asymptomatic carriers.
Some affected individuals have alleles with identical pathogenic mutations
but many have two different mutant alleles and are described as
compound heterozygotes. - ANSWER✔✔-Heterozygotes are always
asymptomatic carriers.
Copyright ©EMILLYCHARLOTE 2025 ACADEMIC YEAR, ALL RIGHTS RESERVED. Page 2/47
,With respect to X-chromosome inactivation in females, which, if any, of the
following statements is incorrect?
X-inactivation first occurs in the preimplantation female mammalian
embryo.
One of the two X chromosomes in each diploid cell of a normal woman is
randomly selected to undergo X-inactivation and becomes highly
condensed.
The process involves epigenetic silencing of each gene on one of the two X
chromosomes, either the maternal X chromosome or the paternal X
chromosome.
Once the decision is made to inactivate a paternal X or the maternal X in a
cell, all descendant cells will continue with that pattern of X-inactivation. -
ANSWER✔✔-The process involves epigenetic silencing of each gene on
one of the two X chromosomes, either the maternal X chromosome or the
paternal X chromosome.
With respect to X-linked recessive inheritance, which, if any, of the
following statements is false?
Copyright ©EMILLYCHARLOTE 2025 ACADEMIC YEAR, ALL RIGHTS RESERVED. Page 3/47
, Males with just one mutant allele are affected because, lacking a second X
chromosome, they do not have a normal allele.
Women are always asymptomatic.
The disorder is not transmitted from fathers to sons.
Each child born to a normal man and a carrier woman has a risk of 1in 4 of
being affected. - ANSWER✔✔-Women are always asymptomatic.
With respect to X-linked dominant inheritance, which, if any, of the
following statements is false?
There are significantly more affected females than males.
Each child born to an affected mother has a risk of 1 in 2 of being affected.
Each daughter born to an affected father has a risk of 1 in 2 of being
affected.
Each boy born to an affected father has a negligible risk of being affected. -
ANSWER✔✔-Each daughter born to an affected father has a risk of 1 in 2
of being affected.
Copyright ©EMILLYCHARLOTE 2025 ACADEMIC YEAR, ALL RIGHTS RESERVED. Page 4/47
