spectrum

Optical spectrum

The optical spectrum ( light or visible spectrum ) is the portion of the electromagnetic spectrum that is visible to the human eye . There a...

Pigment

...by selectively absorbing some parts of the visible spectrum (see light ) whilst reflecting others. A distinction is usually made between a pigment, which is insoluble, and a dye , which is either a liquid, or is soluble. There is no well-defined dividing line between pigments and dyes, however, and some co...

Photosynthesis

...er, other wavelengths are also peaks in the action spectrum for photosynthesis. Photosynthesis begins when light ionizes a chlorophyll molecule, releasing two electrons , which are transferred along an electron transport chain , similar to that involved in respiration. Their energy is used for photophosp...

Photon

...y only a very limited part of the electromagnetic spectrum . Photons have zero invariant mass but a definite finite energy. Because they have energy, the theory of general relativity states that they are affected by gravity , and this is confirmed by observation. Creation Photons can be produced ...

Magnetic resonance imaging

...cal information about that region, as would an NMR spectrum of that region. Functional MRI Functional MRI (fMRI) measures signal changes in the brain that are due to changing neural activity. The brain is scanned at low resolution but at a rapid rate (typically once every 2-3 seconds). Increases in...

Immune system

... and triggered by receptors that recognize a broad spectrum of pathogens. Plants and many lower animals do not possess an adaptive immune system and instead rely on innate immunity. The study of the innate immune system has recently flourished. Earlier studies of innate immunity utilized model organisms that...

Photosynthesis

...er, other wavelengths are also peaks in the action spectrum for photosynthesis. Photosynthesis begins when light ionizes a chlorophyll molecule, releasing two electrons , which are transferred along an electron transport chain , similar to that involved in respiration. Their energy is used for photophosp...

Chlorophyll

... the red and blue portions of the electromagnetic spectrum , thus its intense green color. Chemical structure Chlorophyll is a chlorin pigment, which is structurally similar to porphyrin pigments such as heme . At the center of the chlorin ring is an magnesium ion. This has various side chains, ...

Barbiturate

...ssants , and by virtue of this they produce a wide spectrum of effects, from mild sedation to anesthesia . Some also are used as anticonvulsants . Barbiturates are derivatives of barbituric acid. Contents showTocToggle("show","hide") 1 Medical uses 2 Barbiturate abuse 3 Other non-the...

Biology

... their environment . Biology encompasses a broad spectrum of academic fields that are often viewed as independent disciplines. Together, they study life over a wide range of scales . Life is studied at the atomic and molecular scale in molecular biology , biochemistry , and molecular genetics . ...

Absorption spectrum

An absorption spectrum is a diagram depicting the wavelengths of elec...It can be regarded as the opposite to an emission spectrum , which is a depiction of the specific wavelengths emitted by a material. Let us consider white lig...