Cell and Molecular Biology - Lecture Notes

Cell and Molecular Biology (LQB182) - In-Depth Notes

Lecture 05: Building a Cell

  • Structural Components of Cell Membrane

    • Phospholipids: Form a bilayer, are amphipathic (hydrophilic and hydrophobic parts).

    • Glycoproteins and Glycolipids: Important for cell recognition and signaling.

    • Embedded Proteins: Integral (span the membrane) and peripheral (attached to the surface).

  • Fluid Mosaic Model:

    • Proposed by Singer and Nicolson (1972).

    • Describes the plasma membrane as a fluid structure with a mosaic of various proteins embedded or attached to the phospholipid bilayer.

    • Lipids constitute roughly 50% of the membrane composition.

  • Functions of the Plasma Membrane:

    • Regulates what enters and exits the cell.

    • Facilitates cellular communication and identity through proteins and carbohydrates.

  • Differences Between Cell Types:

    • Prokaryotes: Lack a defined nucleus, have simpler structures (e.g., bacteria).

    • Eukaryotes: Have defined nuclei, more complex organelles (e.g., plant and animal cells).

  • Endosymbiont Theory: An evolutionary theory explaining the origin of eukaryotic cells through symbiosis of prokaryotic cells.