biology-dictionary_11-06-2009

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iphoning
A pipe or tube fashioned or deployed in an inverted U shape and filled until atmospheric
pressure is sufficient to force a liquid from a reservo
Sister chromatids
Replicated forms of a chromosome joined together by the centromere and eventually
separated during mitosis or meiosis II.
Skeletal
The bodily system that consists of the bones, their associated cartilages, and the joints, and
supports and protects the body, produces blood cells, and stores minerals.
Skeletal muscle
Striated muscle generally responsible for the voluntary movements of the body.
Sliding-filament model
The theory explaining how muscle contracts, based on change within a sarcomere, the basic
unit of muscle organization, stating that thin (actin) filaments slide across thick (myosin)
filaments, shortening the sarcomere; the shortening of all sarcomeres in a myofibril
shortens the entire myofibril.
Slime fungi
A group of small simple organisms widely distributed in damp habitats on land. They exist
either as free cells or as multinucleate aggregates of cells.
Slime layer
A slime layer in bacteria is an easily removed, diffuse, unorganized layer of
extracellular material that surround bacteria cells.
Small nuclear ribonucleoprotein (snRNP)
One of a variety of small particles in the cell nucleus, composed of RNA and protein
molecules; functions are not fully understood, but some form parts of spliceosomes, active
in RNA splicing.
Smooth ER
That portion of the endoplasmic reticulum that is free of ribosomes.
Smooth muscle
A type of muscle lacking the striations of skeletal and cardiac muscle because of the uniform
distribution of myosin filaments in the cell.

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