Cell Biology: Prokaryotes vs Eukaryotes

The Cell: Basic Unit of Life

• The cell is the smallest unit of life capable of independent function, including reproduction
• All organisms are composed of cells, adhering to the Cell Theory
• Eggs are the largest and most expensive cells found on Earth, demonstrating that not all cells are microscopic

Cell Types: Prokaryotes and Eukaryotes

• There are two fundamental categories of cells: prokaryotes and eukaryotes
• Prokaryotes lack a nucleus, with their DNA residing directly in the cytoplasm
• Eukaryotes possess a nucleus, which serves as the cell's central control structure containing its DNA
• The presence or absence of a nucleus is the defining feature that distinguishes prokaryotes from eukaryotes

Prokaryotic Cell Structure

• Prokaryotes are structurally simple but exhibit remarkable diversity
• Despite their simplicity, all prokaryotes share four basic structural features

Eukaryotic Cell Structure

• Eukaryotic cells are characterized by compartmentalization with specialized functions, allowing for efficient organization and complex processes
• Organelles are specialized structures within the cytoplasm of eukaryotic cells, each performing a unique function
• Eukaryotic cells are significantly larger than prokaryotes, typically at least ten times bigger
• Eukaryotic cells possess a nucleus, containing the cell's DNA, while prokaryotes lack a nucleus and their DNA is located within the cytoplasm

Plasma Membrane: The Cell Boundary

• Every cell is enclosed by a plasma membrane, serving as a barrier between the cell's internal environment and its surroundings