BIOL 240: Cell Biology Notes

Cell Biology Objectives

  • Understand unifying and defining characteristics of all living organisms.

  • Organelles and cell parts demonstrate form fits function.

The Cell Theory Postulates

  • All living organisms are composed of cells.

  • Cells are the fundamental units of life.

  • All cells originate from pre-existing cells.

  • An organism's activity stems from its cells' activities.

  • Cells of similar species share the same chemical composition.

  • Genetic information is encoded in the cell's genome.

  • Energy flow processes occur within cells.

  • Viruses do not fulfill all modern cell theory postulates, particularly regarding independent reproduction and energy flow.

Cell Characteristics

  • Cells exhibit diverse shapes and sizes (e.g., neurons, epidermal cells, yeast).

  • Cell size varies greatly; for instance, a Mycoplasma is approximately 140 nm140\text{ nm} while an ostrich egg measures 18 cm18\text{ cm}, representing a 90,000×90,000\times difference.

  • Molecules like ribosomes can be represented in various ways, from microscopic images to graphical models.