Microbiology and Immunology

Hydrothermal vents WORLD OF MICROBIOLOGY AND IMMUNOLOGY

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The tendency for hydrophobic regions of a protein of a

lipid molecule to associate away from water is a main driving

force in the folding of proteins into their dimensional config-

uration. Furthermore, the formation of biological membranes

would be extremely difficult in the absence of hydrophobic

and hydrophilic interactions. The biological molecules known

as phospholipidshave a hydrophilic “head” region and a non-

polar, hydrophobic “tail.” These forces cause the phospholipid

molecules to aggregate together so that the polar heads are ori-

ented towards the water and the hydrophobic tails are buried

inside. The effect is to spontaneously establish a membrane.

Insertion of functionally specialized proteins into this so-

called phospholipid bilayer acts to create a biological mem-

brane of great complexity.

See alsoBacterial membranes and cell wall; Biochemical

analysis techniques; Biochemistry; Cell membrane transport;

Membrane fluidity

HHydrothermal ventsYDROTHERMAL VENTS

A hydrothermal vent is a geyser that is located on the floor of

the sea. The first such vent was discovered in 1977 on the floor

of the Pacific Ocean. Since then, vents have been discovered

at a variety of locations in the Pacific and Atlantic Oceans.

The vents tend to be located deep in the ocean. For

example, in the Atlantic ocean, some 7000 feet beneath the

surface, hydrothermal vents are associated with underwater

mountain chain called the Mid-Ocean Ridge. This ridge is

geologically active with an upwelling of hot magma and vol-

canic activity. The tectonic plate movements cause faulting

and seawater that then enters the cracks is superheated by the

molten magma. The superheated water and steam and spews

out through hydrothermal vents.

Some vents, known as “black smokers,” spew out a

black-colored mixture of iron and sulfide. “White smokers”

spew out a whitish mix of barium, calcium, and silicon.

This eruption through the hydrothermal vents is contin-

uous, in contrast with the sporadic eruptions of surface gey-

“Black smoker” hydrothermal vent, with tubes of worms growing to the right.

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