AA

BIOL 215 Lecture 2

Similarities and Differences Between Eukaryotic and Prokaryotic Cells

Similarities

  • They are both surrounded by a lipid-based plasma membrane.
  • Both types of cells have metabolic cellular machinery.
  • Both types use DNA to carry hereditary information.
  • Both types of cells use ribosomes to synthesize proteins.

Differences

  • Prokaryotes do not have a nucleus while eukaryotes do.
  • Eukaryotes have membrane-bound organelles while prokaryotes do not.
  • Eukaryotic cells are much bigger in size than prokaryotic cells.

Cell Size and the Surface Area to Volume Ratio

  • Why is cell size limited?
    • Resource availability
    • Surface area to volume ratio
    • This is important because a cell with a low surface area to volume ratio cannot properly exchange substances between the intracellular and extracellular environments.

Strategies to Overcome the Surface Area to Volume Ratio Limitations

  • Division of cells
  • Halting growth by entering the G0 phase of the cell cycle
  • Folding the membrane to increase surface area
    • This can occur in both the plasma membrane and membranes around the organelles
  • Creating cells that are thin and long
  • Using active transport
  • Multicellularity

Epithelial vs Endothelial Cells

  • Epithelial cells: cells that line the outer or inner surfaces of organs or tissues
  • Endothelial cells: cells that line areas of the cardiovascular system, specifically blood vessels

Cell Fractionation

  • Cells first have to be lysed
    • Lyse: to break open a cell by exposure to chemicals, enzymes, or sound waves
  • Then, homogenization needs to occur
    • Homogenization: blending together the subcellular contents
  • Finally, these parts need to undergo centrifugation
    • Centrifugation: using the centrifugal force to separate different parts of the cell based on density and size
    • The biggest and densest parts of the cell go to the bottom of the centrifuge tube.