With respect to how miRNAs work, which, if any, of the following statements, is false?
a. An miRNA is initially composed of two RNA strands, a passenger strand that will be
destroyed and a complementary RNA, the guide strand, that is required for it to work.
b. an active miRNA regulates target protein-coding genes by binding to
complementary sequences in the mRNA
c. A single miRNA normally binds to transcripts from just one target gene
d. A single type of mRNA can be regulated by multiple different miRNAs.
Give this one a try later!
, c. A single miRNA normally binds to transcripts from just one target gene
With respect to X-chromosome inactivation in females, which, if any, of the following
statements is incorrect?
a. X-inactivation first occurs in the preimplantation female mammalian embryo.
b. 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.
c. 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.
d. 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.
Give this one a try later!
c. 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.
Concerning the efficacy of small molecule drugs, which, if any, of the following
statements is true?
a. At the level of clinical trials drugs can vary widely in how effective they are.
b. Once a drug has received regulatory approval, we can be sure that it will be
effective in all patients, although some people will receive more benefit from it than
others.
c. Drugs used to treat psychiatric disorders are particularly effective.
d. Stains and beta blockers that were meant to reduce the risk of heart disease are
good examples of drugs that are largely ineffective.
Give this one a try later!
, a. At the level of clinical trials drugs can vary widely in how effective they
are.
With reference to imprinting disorders, which, if any, of the following statements is
false?
a. About one quarter of individuals with Angelman syndrome lack a paternal
chromosome 15.
b. With the exception of abnormal chromosome segregation, imprinting disorders
always result from a deletion or inactivating mutation within, or spanning the imprinted
gene cluster.
c. In some imprinting disorders, disease results from inappropriate biallelic expression
of a gene.
d. Angelman and Prader-Willi syndrome are very different disorders but can be
caused by precisely the same large deletion at 15q11-q13.
Give this one a try later!
b. With the exception of abnormal chromosome segregation, imprinting
disorders always result from a deletion or inactivating mutation within, or
spanning the imprinted gene cluster.
1. Which of the following statements is false regarding the sources of genetic
variation?
a. Most of the inherited changes in our DNA arise because of exposure to
extracellular mutagens, including sources of chemical mutagens
b. Significant chemical damage is sustained by DNA because of its proximity to water
molecules in our cells
c. Most of the inherited changes in our DNA arise because of unavoidable
endogenous errors in cellular mechanisms and harmful effects on certain natural
molecules and atoms within our cells
d. Errors in DNA replication and DNA repair are a major source of mutations in our
cells
a. An miRNA is initially composed of two RNA strands, a passenger strand that will be
destroyed and a complementary RNA, the guide strand, that is required for it to work.
b. an active miRNA regulates target protein-coding genes by binding to
complementary sequences in the mRNA
c. A single miRNA normally binds to transcripts from just one target gene
d. A single type of mRNA can be regulated by multiple different miRNAs.
Give this one a try later!
, c. A single miRNA normally binds to transcripts from just one target gene
With respect to X-chromosome inactivation in females, which, if any, of the following
statements is incorrect?
a. X-inactivation first occurs in the preimplantation female mammalian embryo.
b. 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.
c. 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.
d. 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.
Give this one a try later!
c. 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.
Concerning the efficacy of small molecule drugs, which, if any, of the following
statements is true?
a. At the level of clinical trials drugs can vary widely in how effective they are.
b. Once a drug has received regulatory approval, we can be sure that it will be
effective in all patients, although some people will receive more benefit from it than
others.
c. Drugs used to treat psychiatric disorders are particularly effective.
d. Stains and beta blockers that were meant to reduce the risk of heart disease are
good examples of drugs that are largely ineffective.
Give this one a try later!
, a. At the level of clinical trials drugs can vary widely in how effective they
are.
With reference to imprinting disorders, which, if any, of the following statements is
false?
a. About one quarter of individuals with Angelman syndrome lack a paternal
chromosome 15.
b. With the exception of abnormal chromosome segregation, imprinting disorders
always result from a deletion or inactivating mutation within, or spanning the imprinted
gene cluster.
c. In some imprinting disorders, disease results from inappropriate biallelic expression
of a gene.
d. Angelman and Prader-Willi syndrome are very different disorders but can be
caused by precisely the same large deletion at 15q11-q13.
Give this one a try later!
b. With the exception of abnormal chromosome segregation, imprinting
disorders always result from a deletion or inactivating mutation within, or
spanning the imprinted gene cluster.
1. Which of the following statements is false regarding the sources of genetic
variation?
a. Most of the inherited changes in our DNA arise because of exposure to
extracellular mutagens, including sources of chemical mutagens
b. Significant chemical damage is sustained by DNA because of its proximity to water
molecules in our cells
c. Most of the inherited changes in our DNA arise because of unavoidable
endogenous errors in cellular mechanisms and harmful effects on certain natural
molecules and atoms within our cells
d. Errors in DNA replication and DNA repair are a major source of mutations in our
cells
