Bacteria Divide and Multiply

Bacteria are all around us. Given good growing conditions, a bacterium grows slightly in size or length, new cell wall grows through the center, and the "bug" splits into two daughter cells, each with same genetic material. If the environment is optimum, the two daughter cells may split into four in 20 minutes. Oh my! 1, 2, 4, 8, 16, 32, 64... Then why isn't the earth covered with bacteria?

The primary reason may be that conditions are rarely optimum. Scientists who study bacteria try to create the optimum environment in the lab: culture medium with the necessary energy source, nutrients, pH, and temperature, in which bacteria grow predictably.

LAG PHASE: Growth is slow at first, while the "bugs" acclimate to the food and nutrients in their new habitat.

LOG PHASE: Once the metabolic machinery is running, they start multiplying logarithmically, doubling in number every few minutes.

STATIONARY PHASE: As more and more bugs are competing for dwindling food and nutrients, booming growth stops and the number of bacteria stabilizes.

DEATH PHASE: Toxic waste products build up, food is depleted and the bugs begin to die.

550K '.mov' file

Download this time-lapse movie to see how two E. coli, given a suitable environment for growth, divide and form a colony of hundreds of bacteria in just a few hours.

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