Mol bio L5

Which of the following is the MOST accurate definition of an epigenetic trait?

Epigenetic changes are always irreversible modifications to gene expression.

During which of the following stages are crucial epigenetic reprogramming events MOST likely to occur in mammals?

Which of the following BEST describes the focus of epigenetics?

What is the epigenome, and what role does it play in gene expression?

Which of the following factors can influence gene expression, according to the information provided?

What is the primary function of epigenetic events in eukaryotic organisms?

Epigenetic traits play a crucial role in ______ stability by silencing centromeres, telomeres, and transposable elements.

What does the silencing of centromeres, telomeres, and transposable elements via genomic stability ensure?

Which of the following cellular components is directly acted upon by factors influenced by external stimuli, ultimately leading to changes in gene expression patterns?

Match the following lifestyle factors with their potential epigenetic effects:

What is the role of an epigenator in epigenetic regulation?

What is the primary role of the epigenetic initiator?

What are the two main categories of epigenetic initiators described?

Which of the following BEST describes how DNA-binding proteins recognize specific DNA sequences?

Non-coding RNAs (ncRNAs) are translated into proteins.

What is the PRIMARY function of microRNAs (miRNAs) in epigenetic processes?

What is the primary function of short interfering RNAs (siRNAs)?

What is the main function of piwi-interacting RNAs (piRNAs)?

What is the MAIN function of long non-coding RNAs (lncRNAs)?

How does DNA methylation typically affect gene expression?

Where does DNA methylation typically occur, and what base is methylated?

What enzymes are responsible for catalyzing DNA methylation in mammalian cells?

Non-CpG cytosine methylation is MOST prevalent in ______ cells and may be critical in differentiation.

How does an increased level of global methylation typically correlate with differentiation?

Histone modification, defined as a covalent post-translational modification (PTM) to histone proteins, affects which of the following processes within a cell?

Which of the following is NOT a type of histone modification?

On which part of histones do the majority of histone PTMs (post-translational modifications) occur?

How do epigenetic modifications, such as histone modifications, affect the accessibility of DNA to the transcriptional machinery?

What is the function of histone acetyltransferases (HATs)?

How does the addition of an acetyl group affect the interaction between the histone tail and negatively charged DNA?

What is the enzymatic function of histone methyltransferases (HMTs) and histone demethylases (HDMs)?

How does histone phosphorylation typically affect transcriptional activity?

What is the effect of H2A ubiquitination?

What impact does the process of sumoylation have on transcriptional activity?

Which of the following statements accurately describes the characteristics of histone variants?

What is the overall effect of nucleosome remodeling?

In the example provided, which brain area is described as being implicated in the stress response?

The early life environment shapes the stress response later in life through:

What is the term for when the ratio of gene expression levels from two alleles in a diploid genome is not 1 to 1?

Allelic imbalance affects all genes in the genome equally.

What epigenetic phenomenon involves only one of the two copies of a gene being active while the other is silent?

Between 0.5% and 15% of ______ genes exhibit random monoallelic gene expression.

Which of the following best describes somatic rearrangement as a type of monoallelic expression?

Somatic rearrangement in immune cells contributes to antibody diversity.

In the context of somatic rearrangement, what is the mechanism that generates enormous antibody diversity?

Random allelic silencing or activation results in expression from only one gene copy due to different ______ changes.

Which cell type primarily utilizes random allelic silencing or activation in humans?

Genomic imprinting affects the expression of genes based solely on environmental factors.

In genomic imprinting, what is the term for the mechanism by which regions are marked epigenetically?

Epigenetic silencing of a gene copy occurs in ______ regions.

What is the primary purpose of X chromosome inactivation in humans?

In humans, the paternal X chromosome is always inactivated in females.

What type of molecule does the XIST gene encode?

X chromosome inactivation is accomplished by ______ of cytosine, H4 histone hypo-acetylation, and other histone modifications.

Match the following epigenetic mechanisms with their characteristics:

Which of the following best describes the outcome for babies born during the Dutch Hunger Winter whose mothers suffered famine during the last few months of pregnancy?

The Dutch Hunger Winter study showed no correlation between prenatal famine exposure and later-life health outcomes.

What key factor, crucial for human growth and development, is maternally imprinted?

Higher obesity rates are correlated with ______ methylation on the CpG island of an imprinted allele.

What is a classic feature of cancer tissues concerning DNA methylation?

Hypomethylation of oncogene promoters can lead to increased genome stability.

What is generally observed for DNA methylation levels in cancer tissues?

DNA methylation changes may predispose to cancer by inducing a more ______ state.

What epigenetic modification is associated with Rett syndrome?

The MeCP2 protein normally functions as a transcriptional activator.

What epigenetic modification is seen in individuals with addiction to drugs such as cocaine?

In individuals with depression, ______ histone methylation results in the upregulation of repressive methyl marks on H3.

What is one epigenetic change observed in the brains of individuals suffering from depression?

The epigenome is solely determined by an individual's genetic code and is not influenced by environmental factors.

What term describes the function of the epigenome as the key interface between environmental conditions and an individual's genetic makeup?

The ______ is the connection between the environment and genome.

What are the potential consequences of DNA hypomethylation in cancer tissues?

The impact of environmental factors on the epigenome does not have long-lasting effects on human health.

How does the epigenetic landscape in cancer stem cells differ from that in differentiated cells?

When the repressive methyl marks on H3 are upregulated it leads to a down regulation of ______.

What is the primary role of Xist RNA in X-chromosome inactivation?

The process of X-chromosome inactivation always results in the complete and irreversible silencing of all genes on the affected chromosome.