How bacteria metabolize organic and inorganic substances

NARRATOR: The variety of bacterial lifestyles is staggering, from animal-like flesh eaters to plantlike photosynthesizers.

Bacterial photosynthesis, however, can have several unusual twists.

Take purple sulfur bacteria, for instance. These cells have adapted to endure the scalding waters of hot springs.

Reinforcing their cell walls against the fierce heat are special proteins.

Purple sulfur bacteria are photosynthetic [music in], but their biochemistry is very different from that of green plants. Rather than water, these bacteria use hydrogen sulfide as the electron donor in the photosynthetic cycle.

The result is, rather than liberating oxygen gas as a byproduct, these bacteria produce tiny grains of solid sulfur--these dense yellow particles.

[Music out]

It has been said that "if it's edible, there's a bacterium that will eat it," and that's not far from the truth.

There is at least one bacterium specialized to metabolize just about every type of organic material.

The broad appetite of bacteria is the basis for their role as the primary decomposers on Earth.

A bacterium important in the decay of wood and leaves is myxobacteria.

[Music in]

Colonies of these cells glide along the forest floor, absorbing nutrients from the fallen timber.

When food becomes scarce, the cells pile one on another, forming a treelike structure called the fruiting body.

Spores at the top of the fruiting body are carried by the wind to colonize greener pastures.

[Music out]