BIO 203 Although the chromatin structure of interphase and mitotic chromosomes is very compact, DNA-binding proteins and protein complexes must be able to gain access to the DNA molecule. Chromatin-remodeling complexes provide this access by ___.

Altering the extent of DNA supercoiling.

Explanation:

Chromatin Remodeling complexes provides access of transcriptional and regulatory activities to the DNA by changing the chromatin structure which is done by altering the extent of DNA supercoiling. Altering the extent of DNA supercoiling will give rise to a loose chromatin structure that the transcriptional and regulatory activities machinery can have access to. They include factors such as histone chaperones, histone modifying enzymes and ATP-dependent chromatin remodeling complexes.

Such mechanisms which the chromatin undergo include reconstruction: where nucleosomes undergo some compositional changes using special histone variants etc; enzyme induced covalent modification: which include acetylation, methylation, phosphorylation etc of histone tails; repositioning: such as histone chaperones mediating removal of histone from chromatin.

the national environmental policy act (nepa) is a united states environmental law that promotes the enhancement of the environment and established the president's council on environmental quality (ceq). the law was enacted on january 1, 1970. to date, more than 100 nations around the world have enacted national environmental policies modeled after nepa.