Module 1: General Biology 1 - Cell Theory and Cell Structure

Introduction

• Importance of understanding cells as the basic unit of life
• Overview of topics: Prokaryotic cells, Eukaryotic cells, Endomembrane system, and proteins
• Instructor: Miss Joe

Fun Animal Trivia

• Elephants can detect thunderstorms from miles away.
• Dogs can sense human emotions through changes in scent.
• Cats use whiskers to navigate spaces and sleep a lot.

Key Concepts

Cells as the Basic Unit of Life

• Living organisms can be unicellular (single-celled) or multicellular (many cells).
• Two main cell types:
  • Prokaryotic
  • Eukaryotic
• Cells are specialized with specific functions.

Microscopy

• Light Microscopes:
  • Magnification: 400 to 1,000 times.
  • Uses visible light and lens system.
• Electron Microscopes:
  • Uses beams of electrons for higher magnification.
  • Provides clearer visualization of cellular structures.

Cell Theory

• Three main points:
  1. All living things are composed of one or more cells.
  2. Cells are the basic unit of life.
  3. All new cells arise from existing cells.
• Key contributors:
  • Matthias Schleiden
  • Theodor Schwann
  • Rudolf Virchow

Prokaryotic Cells

• Characteristics:
  • Lack organized nucleus and membrane-bound organelles.
  • DNA located in nucleoid region.
  • Cell wall provides protection and shape.
  • Size: 0.1 to 5.0 micrometers.

Eukaryotic Cells

• Characteristics:
  • Larger than prokaryotic cells.
  • Have true nucleus and membrane-bound organelles.
  • Organelles include:
    • Nucleus: houses DNA and directs protein synthesis.
    • Mitochondria: ATP production (powerhouse of the cell).
    • Endoplasmic Reticulum (ER):
      • Rough ER: has ribosomes, synthesizes proteins.
      • Smooth ER: synthesizes lipids, detoxifies drugs.
    • Golgi Apparatus: sorts and packages proteins.
    • Lysosomes: digest macromolecules and foreign substances (only in animal cells).
    • Peroxisomes: detoxify poisons, break down fatty acids.

Plasma Membrane and Cytoplasm

• Plasma Membrane:
  • Composed of a phospholipid bilayer.
  • Regulates passage of materials (passive vs. active transport).
• Cytoplasm:
  • The jelly-like substance where organelles are located.

Differences Between Plant and Animal Cells

• Animal Cells:
  • Have centrosomes and lysosomes.
  • Irregular shape.
• Plant Cells:
  • Have cell walls, large central vacuoles, and chloroplasts for photosynthesis.
  • Define shape due to cell wall rigidity.

Cytoskeleton

• Composed of microfilaments (actin) assisting with cell movement and organelle placement.

Conclusion

• Importance of studying cell structure and functions for understanding biology.
• Final remarks on the significance of healthy cells in overall health.
• Reminder: Review material and complete activities for better understanding.
• Activity 2 will now serve as the midterm performance improvement task (PIT).

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• Note: Please reach out if there are further questions.