Question

Heterochromatin is
A) Darkly stained part of chromatin
B) Lightly stained part of cristae
C) Lightly stained part of grana
D) Scattered lobes in cytoplasm

Answer 1

Heterochromatin is referred to as a condensed DNA. It's a functionally different genomic compartment which has low gene density along with a highly compact chromatin structure.

Complete answer:
Heterochromatin is the darkly stained component of chromatin. Heterochromatin is a firmly packed type of DNA, which comes in various types. These types lie on a series between the two boundaries of constitutive and facultative heterochromatin. Both play a part in the expression of genes. Chromatin is found in two assortments: euchromatin and heterochromatin. Heterochromatin has been related with a few functions, from gene regulation to the security of the integrity of chromosomes; a portion of these roles can be ascribed to the thick packing of DNA, which makes it less available to protein factors that normally bind DNA or its related components.

Additional Information: Constitutive heterochromatin is a certain region of DNA found on the chromosomes of a eukaryotic cell. The constitutive heterochromatin gets dark stained because of the exceptionally consolidated nature of the DNA in these regions. This heterochromatin consists of a high number of repetitive nucleotides.
Facultative heterochromatin is the consequence of genes that are silenced through histone deacetylation process. It isn't dull and shares the smaller structure of constitutive heterochromatin. However, under particular developmental or environmental signals, it can lose its dense structure and become transcriptionally dynamic.

Thus, the correct answer is (A) Darkly stained part of chromatin.

Note: Euchromatin is the chromatin that is expanded and available for transcription though heterochromatin is exceptionally compacted chromatin that isn't open for transcription. As such, heterochromatin is considered as hereditarily inert substance, however euchromatin conveys hereditary genes.