Biology 1010: The Cell

Introduction

• Overview of cell theory and cell structure.
• Components and organelles of cells in living organisms.
• Cells as the basic unit of life.

History of Cell Discovery

• 1665: Robert Hooke discovered cells while looking at oak bark.
• Named them "celluly" (little cells).

Cell Theory

• Three primary components:
  1. All organisms are composed of cells.
  2. Cells are the smallest living things.
  3. Cells arise only from pre-existing cells.
• Implication: All current cells are descendants from the first living cells.

Scale and Microscopy

• Cells in prokaryotes and eukaryotes are larger than viruses.
  • Viruses: ~100 nanometers.
  • Prokaryotic cells: ~1 micrometer.
  • Eukaryotic cells: Larger than prokaryotic cells.

Microscopes

• Light Microscopes: Use light to observe large cells and specific organelles.
• Electron Microscopes: Offer higher magnification; types include:
  • Scanning Electron Microscopes (SEM): Observe surface structures in 3D.
  • Transmission Electron Microscopes (TEM): Observe internal structures.

Types of Cells

• Prokaryotes
  • Extremely small, no compartments, outer membrane, DNA.
• Eukaryotes
  • Have compartments (organelles) like nucleus, mitochondria, etc.

Key Cell Components

Extracellular Matrix (ECM)

• Provides support and anchorage.
• Used for cell signaling.

Cell Wall

• Found in plants, fungi, algae, some protists, and certain bacteria.
• Plant Cell Walls: Made of cellulose.
• Fungal Cell Walls: Made of chitin and other proteins.

Cell Membrane

• Common to all cells (prokaryotic and eukaryotic).
• Made of phospholipids and proteins.
• Responsible for transport, support, and communication.

Cytoplasm and Cytosol

• Cytoplasm: Everything between the cell membrane and nuclear membrane.
• Cytosol: The liquid part of the cytoplasm.

Cytoskeleton

• Network of support and movement within the cell.
• Types of filaments:
  • Microfilaments: Movement and shape, found around cell edge.
  • Microtubules: Support, transport, provide framework.
  • Intermediate Filaments: Attach organelles, maintain cell shape.

Organelles

• Endomembrane System: Site of protein synthesis.
  • Nucleus: Stores genetic information, double membrane, nuclear pores for communication.
  • Endoplasmic Reticulum (ER):
    • Rough ER: Protein synthesis (has ribosomes).
    • Smooth ER: Lipid synthesis.
  • Golgi Apparatus: Modifies, sorts, and packages proteins.
  • Vesicles: Transport materials inside and outside the cell.
• Mitochondria: Powerhouse of the cell, produces ATP, double membrane.
• Chloroplasts: Found in plants, perform photosynthesis, double membrane.
• Central Vacuole: Found in plants, stores water, maintains turgor pressure.

Summary and Review

• Identify organelles in each cell type (animal, plant, fungal, protist) and know their functions.
• Understand the differences in cell structure across different kingdoms.

Additional Resources

• Watch the recommended video on cell structure.
• Review notes and diagrams for better understanding.
• Utilize microscopy to observe cells in the lab.

Conclusion

• Cells are the basic unit of life with complex structures.
• Review and understand cell theory, organelles, and differences between cell types.

Homework/Review

• Review organelles and their functions.
• Study cell theory components.
• Compare and contrast prokaryotic and eukaryotic cells.