Why is it difficult to observe individual chromosomes with a light microscope during interphase?

• A. Because chromosomes are too large to fit within the field of view of a light microscope.
• B. Because the nuclear envelope is dissolved, making chromosomes invisible.
• C. Because chromosomes are in a loosely packed, uncondensed form called chromatin.
• D. Because chromosomes are absent from the nucleus during interphase.

Answer: (C)

Verified step by step guidance

1. Understand the structure of chromosomes during interphase: During interphase, chromosomes are not tightly condensed. Instead, they exist in a loosely packed form called chromatin, which is spread throughout the nucleus.
2. Learn about chromatin: Chromatin is composed of DNA and proteins (histones) and is less dense compared to the condensed chromosomes seen during mitosis. This loose packing makes it difficult to distinguish individual chromosomes under a light microscope.
3. Consider the limitations of light microscopy: Light microscopes rely on visible light to resolve structures. The loosely packed chromatin does not provide enough contrast or distinct boundaries to be easily observed as individual chromosomes.
4. Compare interphase to mitosis: During mitosis, chromosomes condense and become tightly packed, making them visible as distinct structures under a light microscope. This is in contrast to their uncondensed state during interphase.
5. Conclude why chromosomes are difficult to observe: The uncondensed, loosely packed nature of chromatin during interphase is the primary reason individual chromosomes cannot be observed with a light microscope.