Before transcription begins, euchromatin needs to be modified by a chromatin __________.

Before transcription begins, euchromatin needs to be modified by a chromatin __________.

• A. Remodeling complex
• B. DNA polymerase
• C. Ligase
• D. Helicase

Answer: (A)

Opening chromatin to expose DNA is required for transcription. Euchromatin becomes accessible only when nucleosomes are moved or evicted so transcription factors and RNA polymerase II can reach promoter regions. A chromatin remodeling complex uses energy from ATP to reposition or remove these histone-bound blocks, creating the open landscape needed to start transcription. This remodeling often works alongside histone modifications like acetylation that loosen DNA-histone contacts. DNA polymerase, ligase, and helicase are enzymes tied to DNA replication, repair, and strand separation, not the controlled opening of chromatin for transcription.

Opening chromatin to expose DNA is required for transcription. Euchromatin becomes accessible only when nucleosomes are moved or evicted so transcription factors and RNA polymerase II can reach promoter regions. A chromatin remodeling complex uses energy from ATP to reposition or remove these histone-bound blocks, creating the open landscape needed to start transcription. This remodeling often works alongside histone modifications like acetylation that loosen DNA-histone contacts.

DNA polymerase, ligase, and helicase are enzymes tied to DNA replication, repair, and strand separation, not the controlled opening of chromatin for transcription.