Methylation and Acetylation

which is correct?

• heterochromatin-dense, no transcription;

  euchromatin- not dense, transcription

• euchromatin-dense, no transcription;

  heterochromatin- not dense, transcription

• histone acetylation- increase transcription; histone methylation (and DNA methylation)- decrease transcription

• histone methylation- increase transcription; histone acetylation- decrease transcription

A method of turning off transcription and therefore the gene in eukaryotes is DNA ______.

• Acetylation

• Transcription

• Translation

• Methylation

A chemical modification of DNA that does not affect the nucleotide sequence of a gene but makes that gene less likely to be expressed.

• activators

• methylation

• acetylation

• proteins

Epigenetics refers to changes in:

• DNA sequence

• Gene structure

• Gene expression

• DNA frequency

Which of the following help to turn genes on so that they are expressed (transcribed and translated)?

• a high level of condensation (coiling around histones)

• histone acetylation

• DNA methylation

• histone methylation

All of the following are true about DNA methylation EXCEPT

• takes place on the DNA

• enzymes add a methyl group

• when it occurs, transcription is more likely to occur

• chromatin becomes more tightly packed

What is the role of chromatin-modifying enzymes in the regulation of transcription initiation?

• They replicate DNA to ensure there is enough for transcription.

• They provide initial control of gene expression by altering DNA's ability to bind the transcription machinery.

• They bind to RNA polymerase to initiate transcription directly.

• They transport mRNA out of the nucleus.

Can chromatin modifications that do not alter DNA sequence be passed to future generations of cells?

• Yes, but only through maternal lineage

• No, because they do not involve DNA sequence changes

• Yes, they may be passed to future generations of cells

• No, because chromatin modifications are temporary and not heritable

Which process is primarily responsible for decreasing gene expression by adding a methyl group to DNA?

• Acetylation

• Methylation

• Phosphorylation

• Ubiquitination

What is the effect of histone acetylation on chromatin structure?

• Condenses chromatin, reducing transcription

• Loosens chromatin, enhancing transcription

• Has no effect on chromatin structure

• Causes DNA methylation