biology-dictionary_11-06-2009

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Gonads
The male and female sex organs; the gamete-producing organs in most animals.
Graded potential
A local voltage change in a neuron membrane induced by stimulation of a neuron, with
strength proportional to the strength of the stimulus and lasting about a millisecond.
Gradualism
A view of Earth's history that attributes profound change to the cumulative product of slow
but continuous processes.
Gram-negative bacteria
Gream-negative bacteria are those that do not retain crystal violet dye in the Gram staining
protocol.
Gram stain
A staining method that distinguishes between two different kinds of bacterial cell walls.
Granum
A stacked portion of the thylakoid membrane in the chloroplast. Grana function in the light
reactions of photosynthesis.
Gravid
In an advanced stage of pregnancy; "was big with child"; "was great with child"
Gravitropism
A response of a plant or animal in relation to gravity.
Greenhouse effect
The warming of planet Earth due to the atmospheric accumulation of carbon dioxide, which
absorbs infrared radiation and slows its escape from the irradiated Earth.
Gross primary productivity (GPP)
The total primary productivity of an ecosystem.
Gross productivity
A measure of the rate at which energy is assimilated by the organisms in a trophic level, a
community, or an ecosystem.
Ground meristem
A primary meristem that gives rise to ground tissue in plants.

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