Coiled dense, deep stain portions of chromosomes are designated as

Options

A. pellicle
B. heterochromatin
C. euchromatin
D. heterochromosomes

Answer

**Step-by-Step Solution:**

1. **Understanding Chromosomes**: Chromosomes are structures within cells that contain DNA. They are formed by the coiling and condensing of DNA around proteins called histones.

2. **Formation of Chromatin**: The DNA wraps around histone proteins to form a complex known as a histone octamer. This structure is referred to as chromatin.

3. **Coiling of Chromatin**: Chromatin further coils and supercoils to form a dense structure known as a chromosome. This process allows the long strands of DNA to fit within the cell nucleus.

4. **Staining of Chromosomes**: When chromosomes are stained for observation under a microscope, they show different regions based on their density and structure. Some areas of the chromosome take up the stain more intensely than others.

5. **Identification of Chromatin Types**: The darker, more densely stained regions of chromosomes are referred to as heterochromatin. In contrast, the lighter-stained regions are known as euchromatin.

6. **Conclusion**: Therefore, the coiled dense, deep-stained portions of chromosomes are designated as heterochromatin.

**Final Answer**: Heterochromatin

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