What feature in prokaryotes substitutes for the spindle action in eukaryotes ?

Options

A. Looped DNA
B. Elongation of plasma membrane
C. Fission instead of cytokinesis
D. Centricles with asters

Answer

**Step-by-Step Solution:**

1. **Understanding Prokaryotes and Eukaryotes:**
- Prokaryotes are simple, unicellular organisms that lack a true nucleus and membrane-bound organelles. Examples include bacteria.
- Eukaryotes are more complex cells that have a defined nucleus and organelles.

2. **Cell Division in Eukaryotes:**
- Eukaryotic cells undergo mitosis, a process where the genetic material is divided equally between two daughter cells.
- During mitosis, spindle fibers (made of proteins) play a crucial role in aligning and separating chromosomes.

3. **Cell Division in Prokaryotes:**
- Prokaryotes do not undergo mitosis because they lack a nucleus. Instead, they reproduce through a simpler process called binary fission.
- In binary fission, the DNA is attached to the plasma membrane.

4. **Role of Plasma Membrane in Prokaryotes:**
- As the cell prepares to divide, the plasma membrane elongates, and the attached DNA is replicated.
- The elongation of the plasma membrane allows for the separation of the two DNA copies as the cell divides.

5. **Conclusion:**
- The feature in prokaryotes that substitutes for the spindle action in eukaryotes is the elongation of the plasma membrane, which helps in the separation of the genetic material during binary fission.

**Final Answer:**
The feature in prokaryotes that substitutes for the spindle action in eukaryotes is the elongation of the plasma membrane.

---