74. Which one of the following changes occurs in a directionally migrating eukaryotic cell?
(1) The ER is fragmented.
(2) The mitochondrial membrane potential drops.
(3) The nucleus moves towards the back and behind the Golgi.
(4) The Golgi is fragmented.

Introduction:

Cell migration is a crucial process in various physiological and developmental events, such as wound healing, immune response, and tissue development. In eukaryotic cells, migration is highly coordinated, and several cellular structures undergo changes to facilitate efficient movement.

In this article, we will explore the significant changes that occur within eukaryotic cells during directional migration and focus on the fragmentation of specific organelles.

What Happens During Directional Migration in Eukaryotic Cells?

Directional migration refers to the movement of a cell in a specific direction, typically towards a particular signal or gradient (e.g., during immune response or tissue repair). This movement requires a series of cellular reorganizations, which help the cell to move efficiently in the desired direction.

Key Cellular Changes in Migrating Cells:

1. The Fragmentation of the Golgi Apparatus: During cell migration, the Golgi apparatus, a critical organelle responsible for protein processing and transport, undergoes fragmentation. This fragmentation allows the cell to efficiently mobilize vesicles and components to the front of the cell, which are needed for membrane extension and movement.

   Correct Answer:

   • (4) The Golgi is fragmented.

2. Other Changes During Cell Migration:

   • Endoplasmic Reticulum (ER): The ER may fragment to facilitate the movement of proteins and lipids that are essential for the cellular extension required for migration.

   • Mitochondria: While mitochondria are essential for energy production, during directional migration, the mitochondrial membrane potential might drop as energy is used for the propulsion of the cell.

   • Nucleus: The position of the nucleus can shift during migration, but typically, the nucleus tends to move towards the front of the cell, not towards the back.

What Does the Fragmentation of the Golgi Mean?

The fragmentation of the Golgi apparatus during directional migration is an essential event. The Golgi’s fragmentation facilitates the movement of its vesicles to the leading edge of the cell, ensuring that newly synthesized materials such as membrane components are directed towards the front to support cell migration. This is vital for the formation of the leading edge and the extension of lamellipodia or filopodia, which are crucial for forward movement.

Conclusion:

Directional migration in eukaryotic cells involves complex and coordinated changes within the cell. Among these, the fragmentation of the Golgi apparatus plays a central role in supporting cell movement by enabling the distribution of necessary components to the front of the cell. Understanding these processes is vital in research areas such as cancer metastasis, tissue repair, and developmental biology.