General Biology 1: Cell Theory

General Functions of the Cell

• Homeostasis is the ability of organisms to maintain a constant internal state, vital for normal cell function.
• Cells require specific conditions for optimal operation, affected by temperature and energy levels.
• Energy in cells is derived from chemical bonds in food, necessary for activities including:
  • Heart cells pumping blood
  • Intestinal cells digesting food
  • Skeletal cells enabling motion
  • Nerve cells conducting information
• Cells must detect environmental changes to generate appropriate responses, ensuring a stable internal environment.
• Protection is provided through mechanisms such as:
  • Tanned skin, which releases more pigment to protect against UV radiation.
  • Immune cells that defend against pathogens entering the body.

History of the Development of Cell Theory

• Zacharias Janssen invented the first primitive microscope in the early 17th century.
• Robert Hooke examined cork cells under a microscope, introducing the concept of "cells."
• Francesco Redi challenged spontaneous generation with experiments.
• Anton van Leeuwenhoek utilized his microscope to observe microorganisms.
• Matthias Schleiden posited that all plants are made of cells.
• Theodor Schwann suggested that all animals comprise cells.
• Rudolf Virchow established the principle that all cells arise from pre-existing cells.

The Three Principles of Cell Theory

• Principle 1: All living organisms consist of one or more cells, distinguishing unicellular from multicellular organisms based on complexity.
• Principle 2: The cell is the fundamental unit of life, being both the smallest structural and functional unit across all organisms.
• Principle 3: Cells arise from pre-existing cells, with hereditary material passed to daughter cells during division.

General Functions of the Cell

• Homeostasis is the ability of organisms to maintain a constant internal state, vital for normal cell function.
• Cells require specific conditions for optimal operation, affected by temperature and energy levels.
• Energy in cells is derived from chemical bonds in food, necessary for activities including:
  • Heart cells pumping blood
  • Intestinal cells digesting food
  • Skeletal cells enabling motion
  • Nerve cells conducting information
• Cells must detect environmental changes to generate appropriate responses, ensuring a stable internal environment.
• Protection is provided through mechanisms such as:
  • Tanned skin, which releases more pigment to protect against UV radiation.
  • Immune cells that defend against pathogens entering the body.

History of the Development of Cell Theory

• Zacharias Janssen invented the first primitive microscope in the early 17th century.
• Robert Hooke examined cork cells under a microscope, introducing the concept of "cells."
• Francesco Redi challenged spontaneous generation with experiments.
• Anton van Leeuwenhoek utilized his microscope to observe microorganisms.
• Matthias Schleiden posited that all plants are made of cells.
• Theodor Schwann suggested that all animals comprise cells.
• Rudolf Virchow established the principle that all cells arise from pre-existing cells.

The Three Principles of Cell Theory

• Principle 1: All living organisms consist of one or more cells, distinguishing unicellular from multicellular organisms based on complexity.
• Principle 2: The cell is the fundamental unit of life, being both the smallest structural and functional unit across all organisms.
• Principle 3: Cells arise from pre-existing cells, with hereditary material passed to daughter cells during division.