18 Questions
Match the following epigenetic mechanisms with their descriptions:
Histone modifications = Alteration of DNA and/or associated proteins without nucleotide sequence variance DNA methylation = Prokaryotic mechanism for regulating gene expression Chromatin-associated complexes = Regulation of gene expression to generate various cell types during development Noncoding RNAs = Regulation of gene expression in response to external stimuli
Match the following terms with their definitions related to chromatin structure:
Chromatin = A highly compact form of DNA that can fit in the cell nucleus Nucleosomes = A mixture of DNA and proteins that form the chromosomes Histones = Proteins that package the massive amount of DNA in a genome Chromatin-associated complexes = Proteins that regulate gene expression during development
Match the following epigenetic factors with their roles in gene regulation:
Histone modifications = Regulation of gene expression in response to external stimuli DNA methylation = Prokaryotic mechanism for silencing gene expression RNA splicing factors = Post-translational modification of histone proteins Noncoding RNAs = Regulation of gene expression during development
Match the following terms with their descriptions related to histone modifications:
Post-translational modifications = Alteration of histone proteins after their synthesis Histone octamers = Protein structures that comprise the chromatin Gene regulation = Process of controlling the expression of genes Epigenetic inheritance = Transmission of epigenetic information to the next generation
Match the following epigenetic mechanisms with their effects on gene expression:
Histone modifications = Activation or repression of gene expression DNA methylation = Regulation of gene expression during development Chromatin-associated complexes = Silencing of gene expression Noncoding RNAs = Regulation of gene expression in response to external stimuli
Match the following components with their roles in chromatin structure:
Histone proteins = Packaging of DNA in a genome DNA = Protein structure that comprises the chromatin Chromatin-associated complexes = Regulation of gene expression during development Nucleosomes = Beads on a string structure of chromatin
Match the following histone modifications with their effects on chromatin structure:
Histone acetylation = Leads to an inactive, condensed chromatin structure Histone phosphorylation = Involves the addition of a phosphoryl group to histone tails Histone deacetylation = Leads to a transcriptionally active chromatin structure Histone methylation = Not mentioned in the text
Match the following epigenetic mechanisms with their effects on gene expression:
Histone acetylation = Recruits proteins involved in gene repression DNA methylation = Inhibits the binding of transcription factor(s) to DNA Non-coding RNA = Modulates chromatin structure and function Histone phosphorylation = Increases gene expression
Match the following post-translational modifications with their effects on histone tails:
Histone phosphorylation = Adds a methyl group to the C-5 position of the cytosine ring Histone acetylation = Adds a phosphoryl group to histone tails Histone deacetylation = Removes a phosphoryl group from histone tails Histone methylation = Adds an acetyl group to histone tails
Match the following mechanisms with their roles in regulating gene expression:
Transcription factors = Modulates chromatin structure and function DNA methyltransferases = Regulates the transcription of neighboring genes Non-coding RNA = Recruits proteins involved in gene repression Histone modifications = Regulates gene expression by inhibiting the binding of transcription factor(s) to DNA
Match the following histone modifications with their respective enzymes:
Histone methylation = Histone methyltransferases (HMTs) Histone demethylation = Histone methyltransferases (HMTs) Histone acetylation = Histone demethylases (HDMs)
Match the following epigenetic modifications with their effects on gene expression:
Histone methylation = Bolster gene expression Histone demethylation = Reduce gene expression Histone acetylation = Bolster gene expression
Match the following epigenetic marks with their effects on chromatin structure:
Histone acetylation = Leads to an inactive, condensed chromatin structure DNA methylation = Modulates chromatin structure and function Histone phosphorylation = Leads to a transcriptionally active chromatin structure Non-coding RNA = Involves the cellular response to DNA damage
Match the following mechanisms with their roles in chromatin remodeling:
Histone phosphorylation = Inhibits the binding of transcription factor(s) to DNA Histone acetylation = Involves the cellular response to DNA damage DNA methylation = Modulates chromatin structure and function Non-coding RNA = Plays a part in chromatin remodeling
Match the following histone modifications with their locations on histone proteins:
Histone methylation = N-terminal tails Histone acetylation = Lysine residues within the N-terminal tail Histone demethylation = N-terminal tails
Match the following post-translational modifications with their effects on chromatin structure:
Histone methylation = Loosens chromatin structure Histone demethylation = Tightens chromatin structure Histone acetylation = Loosens chromatin structure
Match the following epigenetic modifications with their regulation of chromatin structure:
Histone methylation = Regulates chromatin accessibility Histone demethylation = Regulates chromatin compactness Histone acetylation = Regulates chromatin compactness
Match the following histone modifications with their effects on histone protein interactions:
Histone methylation = Alters histone interactions with nuclear proteins Histone demethylation = Alters histone interactions with DNA Histone acetylation = Alters histone interactions with nuclear proteins
Study Notes
Chromatin and Epigenetics
- Chromatin refers to a mixture of DNA and proteins that form the chromosomes found in the cells of humans and other higher organisms.
- Histones package the massive amount of DNA in a genome into a highly compact form that can fit in the cell nucleus.
- Nucleosomes are composed of histones (beads) and DNA (string).
Epigenetic Factors
- Epigenetics is the study of stable alterations in gene expression potentials that arise during development and cell proliferation, or alterations in DNA function without alteration in DNA sequence.
- Epigenetic mechanisms regulate expression of the genome to generate various cell types during development or orchestrate cellular responses to external stimuli.
- Epigenetic factors include histone modifications, DNA methylation, chromatin-associated complexes, noncoding RNAs, and RNA splicing factors.
Histone Modifications
- Histones are primary protein components of eukaryotic chromatin and play a role in gene regulation.
- Histone modifications impact chromatin structure and gene expression by making the DNA more or less accessible to transcription.
- Histone modifications include histone acetylation/deacetylation, histone phosphorylation, histone methylation, and histone demethylation.
Histone Acetylation and Deacetylation
- Histone acetylation adds an acetyl group to histone proteins, making the DNA more accessible to transcription (euchromatin).
- Histone deacetylation removes an acetyl group, making the DNA less accessible to transcription (heterochromatin).
Histone Phosphorylation
- Histone phosphorylation involves the addition of a phosphoryl group to histone tails, which can play a part in chromatin remodeling and cellular response to DNA damage.
DNA Methylation
- DNA methylation is a heritable epigenetic mark involving the covalent transfer of a methyl group to the C-5 position of the cytosine ring of DNA by DNA methyltransferases (DNMTs).
- DNA methylation regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s) to DNA.
Non-Coding RNA
- Non-coding RNA regulates gene expression at multiple levels by interacting with DNA, RNA, and proteins.
- Non-coding RNA can modulate chromatin structure and function, transcription of neighboring and distant genes, and affect RNA splicing, stability, and translation.
Histone Methylation and Demethylation
- Histone methylation involves the transfer of methyl groups to histone proteins via histone methyltransferases (HMTs).
- Histone demethylation is the removal of methyl groups from histone tails catalyzed by histone demethylases (HDMs).
- Histone methylation and demethylation have the power to reduce or bolster gene expression, especially as a result of altering chromatin structure.
Test your understanding of histone acetylation and deacetylation, their impact on chromatin structure and gene expression. Learn how histone modifications, such as phosphorylation, affect chromatin structure and transcription.
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