STEM Stream Tutorial: Cell Theory

Introduction

• Cell Theory: A foundational scientific concept establishing that all living organisms are made up of cells.
• Importance: Essential for understanding life and a significant historical scientific advancement.

Historical Context

• Microscope Technology: Advanced rapidly, allowing scientists to observe cells.
• Cell Definition: Cells described as "small rooms," first observed in oak tree bark.

Key Figures

• Robert Hooke (17th Century):
  • First discovered cells using a 230x magnification microscope.
  • Analyzed oak tree bark, identifying compartments termed "cells."
• Anton Van Leeuwenhoek:
  • Built advanced microscopes with 300x magnification.
  • Observed protozoa and bacteria, calling them "animalcules."
  • First to observe human red blood cells and sperm cells, challenging spontaneous generation.

Development of Cell Theory

• Mid-1800s:
  • Developed by Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow.
  • Consolidated as a theory with contributions from earlier scientists like Hooke and Leeuwenhoek.

Core Concepts of Cell Theory

1. All living organisms are composed of one or more cells.
2. The cell is the most basic unit of life.
3. All cells arise only from pre-existing cells.
   • This component was controversial as it countered the belief in spontaneous generation.

Disproving Spontaneous Generation

• Louis Pasteur's Experiments:
  • Swan-neck flask experiments demonstrated that life does not spontaneously arise, supporting cell theory.

Modern Additions to Cell Theory

• Cells in multicellular organisms function together to enable complex life forms.
• Energy flow and genetic information (DNA) are intrinsic to cellular activity.
• Cells of similar species share a basic composition.

Conclusion

• Significance of Cell Theory:
  • Revolutionized understanding of life.
  • Continues to evolve with scientific advancements.
• Ongoing Research:
  • The theory remains a focus of research and debate, especially in spontaneous generation.

Recap

• Cells were first observed by Robert Hooke and Anton Van Leeuwenhoek in the 17th century.
• The controversial idea that cells come from pre-existing cells was confirmed by Louis Pasteur.
• The cell theory continues to be a vital part of scientific research and discussion.

• Note: Advances in cell theory are ongoing, reflecting the dynamic nature of science.