BIO 30_Quiz 6 Review

Epigenetics is the study of mechanisms of regulating gene expression based on:

• transcriptional and post transcriptional mechanisms
• the changes in the DNA sequence
• developmental processes
• modification of the DNA but not its base sequence

Which is INCORRECT regarding epigenetics?

• Methylation patterns are not passed on from cell to cell, but acetylation patterns are heritable epigenetic marks.
• Epigenetics is concerned with changes in phenotype that are not due to changes in the DNA sequence.
• By analyzing epigenetic mechanisms, heritable modified gene expression patterns resulting from different environmental factors can be studied.
• The field of epigenetics explores causal interactions between genes and their products.

Which of the following events will generally lead to gene silencing?

• histone acetylation
• all of the choices
• histone demethylation
• DNA hypermethylation

Methyl groups attached to the DNA can _____________________

• promote binding of transcription factors.

• cause mutation of the DNA sequence.

• regulate the timing and degree of gene expression.

• degrade the gene to which it is attached and inhibit its translation.

Addition of positively charged acetyl groups to histone results in :

• loosening of the association between DNA and histone
• access of DNA by enzymes that can cut the DNA
• all choices are correct
• binding of transcription factors to DNA

The discovery of RNA interference is attributed to _______________.

• Worth and Holliday.
• None of these choices.
• Waddington and Noble
• Mello and Fire

The following statements correctly describe RNA interference (RNAi) except

• none of the choices.
• RNAi delays the expression of a target gene.
• MicroRNAs (miRNA) and short interfering RNAs (siRNA) are used for RNAi.
• Small interfering RNAs can regulate mRNA stability.

Which of the following can regulate apoptosis, signaling, and development?

• microRNA
• RNA interference
• small interfering RNA
• none of the choices

Epigenetic changes are irreversible.

• True / Correct
• False / Incorrect
• None of these

Which of the following examples depicts an epigenetic change? 1. Green, variegated, and albino Agave plants differ in photosynthetic pigments due to differential chromatin compaction in cells of various plant types within the species. 2. Flowers of the hybrid produced from a cross of a red-flowered snapdragon by a white-flowered snapdragon are colored pink. 3. In fowl, novel comb phenotypes are produced due to the interaction of two gene loci.

• example 1 only
• example 2 only
• example 3 only
• examples 1 and 3
• examples 2 and 3