Characteristics of Prokaryotic Cells:

• Lack of nucleus: Prokaryotic cells do not have a true nucleus. Instead, their genetic material is located in the nucleoid region.
• Small size: Prokaryotic cells are generally smaller in size compared to eukaryotic cells.
• Lack of membrane-bound organelles: Prokaryotic cells do not contain membrane-bound organelles such as mitochondria, endoplasmic reticulum, or Golgi apparatus.
• Simple structure: They have a simpler internal structure compared to eukaryotic cells.
• Presence of cell wall: Prokaryotic cells have a rigid cell wall, which provides structural support and protection.
• Circular DNA: The genetic material in prokaryotic cells is present in the form of a single, circular DNA molecule.
• Ribosomes: They contain ribosomes that are smaller in size (70S) compared to eukaryotic ribosomes (80S).

Functions of Prokaryotic Cells:

Prokaryotic cells carry out all the necessary functions for life, including:

• Reproduction: Prokaryotic cells reproduce through binary fission, where the genetic material is replicated and the cell divides into two identical daughter cells.
• Metabolism: They carry out various metabolic processes such as respiration, photosynthesis (in some species), and synthesis of essential molecules.
• Response to stimuli: Prokaryotic cells can respond to changes in their environment, allowing them to adapt to different conditions.
• Genetic information storage and expression: The genetic material in prokaryotic cells contains the instructions for cellular functions and inheritance of traits.

Comparison with Eukaryotic Cells:

It's important to understand the differences between prokaryotic and eukaryotic cells:

1. Nucleus: Prokaryotic cells lack a nucleus, while eukaryotic cells have a true nucleus where the genetic material is enclosed within a membrane.
2. Organelles: Eukaryotic cells contain membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, which are absent in prokaryotic cells.
3. Size: Prokaryotic cells are generally smaller in size compared to eukaryotic cells.
4. Genetic material: Prokaryotic cells have a single, circular DNA molecule, while eukaryotic cells have linear DNA molecules contained within the nucleus.

Examples of Prokaryotic Cells:

Prokaryotic cells are found in a variety of organisms, including:

• Bacteria: This includes diverse species such as Escherichia coli, Bacillus subtilis, and Streptococcus pneumoniae.
• Archaea: These organisms are known for their ability to thrive in extreme environments such as hot springs, deep-sea hydrothermal vents, and salt flats.