What is the Difference Between Interphase Chromatin and Mitotic Chromosomes

The key difference between interphase chromatin and mitotic chromosome is the structural appearance of the chromatin when observed under the microscope. While interphase chromatin appears as thread-shaped structures, mitotic chromosomes appear as distinct rod-shaped structures.

Interphase and mitosis are two important phases of cell division. Interphase is the longest phase of cell division, and mitosis is the shortest phase of cell division. Interphase is present between two successive mitosis phases. Chromosomes present in the two stages consist of different biochemical properties. In addition, they have distinct structural differences as well.

CONTENTS

1. Overview and Key Difference
2. What is Interphase Chromatin 
3. What is Mitotic Chromosome
4. Similarities – Interphase Chromatin and Mitotic Chromosomes
5. Interphase Chromatin vs Mitotic Chromosomes in Tabular Form
6. Summary – Interphase Chromatin vs Mitotic Chromosomes

What is Interphase Chromatin?

Interphase chromatin is a thread-shaped chromosome that is present in the interphase of cell division. During interphase, chromatin appears diffused and unorganized. Hence, they are not clearly visible. These thread-shaped structures are present at the interphase for a longer time accumulating nutrients, synthesizing proteins, and generating new organelles.

Figure 01: Basic Unit of Chromatin Organization in the Nucleosome

The generation of new organelles helps in replicating DNA. At the end of the interphase, the cell becomes ready to process into the mitotic stage. At this level, significant changes take place in the interphase chromatin. The most visible change is the condensation process. Interphase chromatin undergoes different changes at three sub-stages of interphase. They are G1 phase, S phase, and G2 phase. Condensation occurs at G2 phase. During condensation, an SMC protein known as condensin binds to a single interphase chromatin at different locations, twisting the chromatin to different coils and lops. This makes the interphase chromatin into distinct rod-shaped structures that will enter mitosis later.

What are Mitotic Chromosomes?

Mitotic chromosomes are distinct rod-shaped, highly condensed chromosomes that are present in the mitotic phase of cell division. Mitotic chromosomes are very distinct due to the shape and the amount of condensation. This occurs at the interphase of the cell cycle with the involvement of condensin, an SMC protein. Mitotic chromosomes will undergo different biochemical changes under four sub-stages of mitosis. They are prophase, metaphase, anaphase, and telophase.

Figure 02: Mitosis

During the mitotic phase, mitotic chromosomes are attached to a structure known as the mitotic spindle. Mitotic chromosomes line up at the metaphase plate. Microtubules connect with the centrosomes of the lined up mitotic chromosomes. During anaphase, the mitotic chromosomes (sister chromosomes) split evenly. Next, they move towards opposite poles. During telophase, the new cell contents start to form at the two ends, forming two new cells followed by cytokinesis.

What are the Similarities Between Interphase Chromatin and Mitotic Chromosomes?

• Interphase chromatin and mitotic chromosomes are types of chromosomes.
• Both types are involved in the cell cycle.
• They are composed of DNA
• Both types are essential for the growth and reproduction of multicellular organisms.

What is the Difference Between Interphase Chromatin and Mitotic Chromosomes?

The key difference between interphase chromatin and mitotic chromosomes is that interphase chromatin appears as thread-shaped structures while mitotic chromosomes appear as distinct rod-shaped structures. Moreover, interphase chromatins are less condensed, while mitotic chromosomes are heavily condensed.

The below infographic presents the differences between interphase chromatin and mitotic chromosomes in tabular form for side by side comparison.

Summary – Interphase Chromatin vs Mitotic Chromosomes

Interphase chromatin appears as thread-like structures with less condensation. Mitotic chromosomes appear as distinct rod-shaped structures, and they are heavily condensed. Both interphase chromatin and mitotic chromosomes are essential for the cycle of cell division. Both types undergo different biochemical changes relative to their functions. So, this is the summary of the difference between interpahse chromatin and mitotic chromosomes.

Reference:

1. “Chromosomes.” Scitable by Nature Education, Nature Publishing Group.
2. Batty, Paul, and Daniel W. Gerlich. “Mitotic Chromosome Mechanics: How Cells Segregate Their Genome.” Trends in Cell Biology, Elsevier Current Trends.

Image Courtesy:

1. “The basic unit of chromatin organization is the nucleosome, which comprises 147 bp of DNA wrapped ar” By Sha, K. and Boyer, L. A. The chromatin signature of pluripotent cells (May 31, 2009), StemBook, ed. The Stem Cell Research Community, StemBook (CC BY 3.0) via Commons Wikimedia
2. “Mitosis schematic diagram-en” By Original: Jpablo cad and juliana osoriotranslation: MattDerivative work: M3.dahl – (CC BY-SA 3.0) via Commons Wikimedia

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