Cell Structure and Function: Life is Cellular

The foundation of modern biology rests on our understanding of cellular organization and the modern cell theory. This page explores the historical development of cell theory and the fundamental differences between prokaryotic and eukaryotic cells.

Definition: Cells are the smallest functional units of life capable of performing all biological processes.

Highlight: Robert Hooke made the first cell observation in 1665 using an early compound microscope to examine cork tissue, while Anton van Leeuwenhoek became the pioneer in observing living cells through his single-lens microscope.

The three fundamental principles of cell theory 3 parts state:

1. All living organisms are composed of one or more cells
2. Cells serve as the basic units of structure and function in living things
3. New cells arise only from pre-existing cells

Example: The distinction between prokaryotes vs eukaryotes is demonstrated through key structural differences:

• Prokaryotes: No nucleus, simpler organization, smaller size $1-10 μm$, evolved 3.5 billion years ago
• Eukaryotes: Nucleus present, complex organelles, larger size $2-1000 μm$, evolved 1.5 billion years ago

Vocabulary:

• Prokaryotes: Organisms whose cells lack a membrane-bound nucleus
• Eukaryotes: Organisms whose cells contain a true nucleus and membrane-bound organelles
• Endosymbiotic theory: Explains the origin of certain organelles through the incorporation of primitive prokaryotic cells

The page includes detailed illustrations comparing prokaryotic and eukaryotic cell structures, highlighting their shared features (cell membrane, DNA, ribosomes) and distinctive characteristics.