Modifications to chromatin can affect transcriptional activity by changing the accessibility of DNA to the transcription machinery. a. True
b. False

True  

Explanation:

DNA packaging in chromatin and the modifications are fundamental to the genetic expression.

Structure and modifications of chromatin regulate DNA metabolic processes, including transcription, recombination, reparation, etc.  

Modifications that affect the way in which the DNI is packaged and used, but do not affect DNI sequences, are known as epigenetic modifications, and different enzymes are in charge of them.

Modifications might function by interfering between nucleosomes contact, or interacting with effector, or translating proteins.

Effector proteins initiate biological responses such as the activation or repression of transcription.

Packaging in chromatin has a big influence on genetic transcription. Genetic expression requires transcription factors that, once joined to genes regulatory sequences, initiate modification cascades that result in a gene expression or silence. Some of the chromatin modifications have been associated with genic activation or repression.