Chapter 6.1

A Tour of the Cell

Microscopy Methods

  • Light Microscopy (LM): Uses visible light to magnify images of specimens.

    • Parameters:

      • Magnification: Up to 1,000 times.

      • Resolution: Limited to ~0.2 µm.

      • Contrast: Enhanced through staining and labeling.

  • Electron Microscopy (EM): Uses electron beams for higher resolution (up to ~0.002 nm).

    • Types of EM:

      • Scanning Electron Microscope (SEM): 3D images of surfaces.

      • Transmission Electron Microscope (TEM): Visualizes internal structures by transmitting electrons through thin specimens.

Cell Structure and Function

Eukaryotic vs Prokaryotic Cells

  • Prokaryotic Cells: Simple structure lacking a nucleus; DNA in nucleoid region.

  • Eukaryotic Cells: Complex structure with a nucleus; membrane-bound organelles.

Components of Eukaryotic Cells

  • Nucleus: Houses DNA; site of ribosome assembly (nucleolus).

  • Endoplasmic Reticulum (ER):

    • Rough ER: Studded with ribosomes; synthesizes proteins.

    • Smooth ER: Lacks ribosomes; synthesizes lipids and detoxifies.

  • Golgi Apparatus: Modifies, sorts, and ships proteins and lipids.

  • Lysosomes: Contains enzymes for digestion of macromolecules.

  • Vacuoles: Storage sites for various functions; central vacuole in plants aids in growth.

Energy Transformations

  • Mitochondria: Site of cellular respiration; converts nutrients into ATP.

  • Chloroplasts: Site of photosynthesis; converts solar energy into chemical energy.

Cytoskeleton Structure and Function

  • Microtubules: Hollow tubes providing structure and tracks for organelle movement.

  • Microfilaments: Thin rods aiding in cell shape and muscle contraction.

  • Intermediate Filaments: Provide structural support and anchorage for organelles.