GCD 3022 EXAM THREE QUESTIONS
COMPLETE WITH 100% VERIFIED
ANSWERS
\.1. A drug, which we will call drug X, inhibits the protein kinase that
phosphorylates the CREB protein.
How would drug X affect the following events?
A. The ability of the CREB protein to bind to CREs
B. The ability of extracellular hormone to enhance cAMP levels
C. The ability of the CREB protein to stimulate transcription
D. The ability of the CREB protein to dimerize - ANSWERS-A, B and D: no effect
C: would inhibit the CREB proteins ability to stimulate transcription
\.Define
combinatorial control
? Why is strategy important for eukaryotes? - ANSWERS-Combinatorial control
refers to the phenomenon that any given gene is regulated in
multiple ways. These include the effects of activators, repressors, changes in
chromatin
structure, and methylation. Combinatorial control allows an organism to regulate
its genes in
, a complex way. It is important so that eukaryotes can (1) respond to
environmental changes,
(2) produce different cells types within multicellular species, and (3) express genes
at the
correct stage of development.
\.Drug X inhibits histone acetyltransferase. Describe how this drug might affect
transcriptional
initiation and how it might affect elongation. - ANSWERS-The acetylation of
histones loosens the contact between DNA and histones. This
makes it easier to evict histones, which is needed for both transcriptional
initiation and
elongation. Therefore, the drug would tend to inhibit both of these processes.
\.List four types of molecular events that may underlie epigenetic gene regulation.
- ANSWERS-1. DNA methylation-the attachment of methyl groups to cytosines in
DNA. This often silences
transcription.
2. Covalent histone modification-the covalent attachment of groups to the amino
terminal tails
of histones. This may silence or activate genes.
3. Chromatin remodeling-changes in the positions of nucleosomes. This may lead
to a closed
or open conformation for transcription.
4. Histone variants-replacement of standard histones for histone variants. This
may silence or
COMPLETE WITH 100% VERIFIED
ANSWERS
\.1. A drug, which we will call drug X, inhibits the protein kinase that
phosphorylates the CREB protein.
How would drug X affect the following events?
A. The ability of the CREB protein to bind to CREs
B. The ability of extracellular hormone to enhance cAMP levels
C. The ability of the CREB protein to stimulate transcription
D. The ability of the CREB protein to dimerize - ANSWERS-A, B and D: no effect
C: would inhibit the CREB proteins ability to stimulate transcription
\.Define
combinatorial control
? Why is strategy important for eukaryotes? - ANSWERS-Combinatorial control
refers to the phenomenon that any given gene is regulated in
multiple ways. These include the effects of activators, repressors, changes in
chromatin
structure, and methylation. Combinatorial control allows an organism to regulate
its genes in
, a complex way. It is important so that eukaryotes can (1) respond to
environmental changes,
(2) produce different cells types within multicellular species, and (3) express genes
at the
correct stage of development.
\.Drug X inhibits histone acetyltransferase. Describe how this drug might affect
transcriptional
initiation and how it might affect elongation. - ANSWERS-The acetylation of
histones loosens the contact between DNA and histones. This
makes it easier to evict histones, which is needed for both transcriptional
initiation and
elongation. Therefore, the drug would tend to inhibit both of these processes.
\.List four types of molecular events that may underlie epigenetic gene regulation.
- ANSWERS-1. DNA methylation-the attachment of methyl groups to cytosines in
DNA. This often silences
transcription.
2. Covalent histone modification-the covalent attachment of groups to the amino
terminal tails
of histones. This may silence or activate genes.
3. Chromatin remodeling-changes in the positions of nucleosomes. This may lead
to a closed
or open conformation for transcription.
4. Histone variants-replacement of standard histones for histone variants. This
may silence or
