[Campbell Biology P.420] Based on Figure 18.7b, which of the following statements is true re... | Practice Question

Based on Figure 18.7b, which of the following statements is true regarding the relationship between histone acetylation, chromatin structure, and DNA accessibility?

  • A: Unacetylated histones are associated with loose chromatin, making DNA accessible for transcription.
  • B: Acetylation of histone tails leads to a more condensed chromatin arrangement, inhibiting transcription.
  • C: When nucleosomes become highly acetylated, the chromatin becomes less condensed, and the DNA is accessible for transcription.
  • D: DNA is always accessible for transcription regardless of histone modifications.

Explanation

Figure 18.7b illustrates that when nucleosomes are unacetylated, the chromatin is condensed, and DNA is not accessible for transcription. Conversely, when nucleosomes become highly acetylated, the chromatin becomes less condensed, allowing DNA to be accessible for transcription.