Which of the following is true of DNA during interphase?
View Available Hint(s)
It exists as chromatin and is unavailable for gene expression.
It exists as chromatin; it is completely uncoiled and loose.
It is in the form of highly condensed chromosomes; it is called heterochromatin.
It is in the form of highly condensed chromosomes and is unavailable for gene expression.
It exists as chromatin and is less condensed than mitotic chromosomes.
Previous Answers
The Correct Answer and Explanation is:
Correct Answer: It exists as chromatin and is less condensed than mitotic chromosomes.
Explanation
During interphase, which encompasses the G₁, S, and G₂ phases of the cell cycle, the cell is actively engaged in metabolic activities and preparing for cell division. One of the key characteristics of interphase is the organization of DNA within the nucleus.
Instead of being tightly packed into visible chromosomes as seen during mitosis, DNA in interphase exists as chromatin, a less condensed and more loosely organized form. Chromatin is composed of DNA wrapped around histone proteins, forming nucleosomes that further coil and fold into more compact structures. However, compared to mitotic chromosomes, this chromatin remains significantly less condensed, which is crucial for its function during interphase.
The less condensed state of chromatin allows access to the DNA for important processes such as transcription (gene expression), DNA replication (during the S phase), and DNA repair. This is why chromatin during interphase is considered to be functionally active, especially euchromatin, which is loosely packed and transcriptionally active. In contrast, heterochromatin remains more tightly packed and is generally transcriptionally inactive.
The chromatin structure during interphase is dynamic and changes in response to cellular needs. For example, when a gene is to be expressed, chromatin remodeling proteins can make that region more accessible to transcription factors and RNA polymerase.
To summarize:
DNA exists as chromatin (not visible as distinct chromosomes under a light microscope).
It is less condensed than during mitosis, enabling gene expression and replication.
This state is essential for the cell’s normal functions and preparation for division.
Thus, the most accurate and comprehensive choice is:
It exists as chromatin and is less condensed than mitotic chromosomes.
