Correct option is C
Explanation-
Statement A: Chromatin remodeling completely alters and/or slides the nucleosome, but cannot displace it.
Incorrect
Chromatin remodelers can slide, eject, or restructure nucleosomes. Displacement (ejection) of histones is possible and has been shown to occur in several remodeling processes.
So saying they “cannot displace it” is false.
Statement B: Chromatin remodeling is an energy driven, developmentally regulated active process.
Correct
Chromatin remodeling is ATP-dependent and involves chromatin-remodeling complexes like SWI/SNF, ISWI, etc. These are highly regulated in development and differentiation.
So this statement is accurate.
Statement C: Histone acetylation is a reversible process, in which each direction of the reaction is catalyzed by different enzymes.
Correct
Histone acetyltransferases (HATs) add acetyl groups. Histone deacetylases (HDACs) remove acetyl groups. This bidirectional enzymatic action makes it reversible and regulated.
Therefore, this is true.
Statement D: In general, acetylation of core histones reduces their affinity for DNA and destabilizes the chromatin structure, causing transcriptional repression.
Incorrect
The first part is true: acetylation reduces positive charge on histones, weakening their binding to DNA → more open chromatin. But the conclusion is false: acetylation promotes transcription, not repression.
So, this statement is contradictory/misleading.
Statement E: Phosphorylation of Ser1 of histone H2A has been associated with transcription repression.
Correct
Phosphorylation of H2A at Ser1 is linked to gene silencing, heterochromatin formation, and transcriptional repression. This is a known epigenetic modification that suppresses gene expression.
Hence, this statement is correct.
So, the correct answer is option c - B, C and E
