Célula Procariota

What Are Prokaryotic Cells?

Introduction to Prokaryotic Cells

• The cell is the fundamental organized structure of living beings, essential for performing life functions.

• Prokaryotic cells are the oldest known type of cell, existing on Earth for approximately 3.5 billion years.

• Despite their age, prokaryotic cells have not evolved significantly; some theories suggest that various prokaryotic bacteria may have formed symbiotic relationships leading to more complex eukaryotic cells.

Characteristics of Prokaryotic Cells

• Prokaryotic cells come in various shapes: spherical (cocci) and rod-shaped (bacilli). They are much smaller than eukaryotic cells.

• A defining feature of prokaryotic cells is the absence of membrane-bound organelles; they lack a well-defined nucleus where DNA is stored, resulting in DNA being dispersed in cytoplasmic clusters.

Structure of Prokaryotic Cells

• Key structures include:

• Plasma Membrane: Protects the cell and regulates internal processes.

• Cell Wall: Provides rigidity and additional protection.

• Capsule: Allows adherence to surfaces and retains moisture within the cell.

Additional Structures

• Other important components:

• Pili: Hair-like projections that facilitate attachment to substances and transfer DNA.

• Ribosomes: Essential for protein synthesis with assistance from RNA.

• Cytoplasm: Gel-like substance enabling movement and housing cellular structures.