Final answer:
Prokaryotic cells are unicellular organisms without a nucleus and are much smaller and simpler than eukaryotic cells. They belong to the domains Bacteria and Archaea, have a rigid cell wall, and reproduce asexually. They are ubiquitous, found in diverse environments, and are essential for nutrient recycling and ecosystem development.
Step-by-step explanation:
What are prokaryotic cells almost always? Prokaryotic cells are unicellular organisms, which means they consist of a single cell. They are characterized by their lack of a nucleus and other membrane-bound organelles, making them distinct from eukaryotic cells.
The DNA in prokaryotes is typically a single large circular strand that resides in the central part of the cell, known as the nucleoid. Outside the plasma membrane, most prokaryotes possess a rigid cell wall that helps maintain cell structure and protection. These organisms can be found everywhere due to their ability to thrive in various environments, from extreme heat to high salt concentrations.
Prokaryotic cells, notably those belonging to the domains Bacteria and Archaea, reproduce asexually and have been present on Earth for approximately 4 billion years. They play a crucial role in recycling nutrients and driving the evolution of new ecosystems.