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In botany, a herbarium is a collection of preserved plant specimens. These specimens may be whole plants or plant parts: these will usually be in a dried form, mounted on a sheet, but depending upon the material may also be kept in alcohol or other preser
Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show the greatest diversity in methods of reproduction of all biological systems.
This organism is widespread in the environment, but rare in the flora of healthy individuals. Its carriage increases with hospitalization.
Column chromatography is one of many forms of chromatography. Others include paper, thin-layer, gas, and HPLC. Most forms of chromatography use a 2-phase system to separate substances on the basis of some physical-chemical property.
Protiens are polymers of amino acids joined by peptide bonds (proteins are therefore also known as polypeptides). The number and order of the amino acids contained in a particular protein are prescribed by the DNA sequence of that protein?s gene.
Bilateral nervous systems, the simplest of which occur in flatworms, represent a distinct increase in complexity over the nerve net of radiate animals.
Plants appeared on land about 425 million years ago and the evolutionary history of the plant kingdom reflects increasing adaptation to the terrestrial environment. Plants have organs and organ systems.
The biosphere as usually defined is the thin outer layer of the earth capable of supporting life. It is probably best viewed as a global system that includes all life on earth and the physical environments in which living organisms exist and interact.
A bacteriophage is a virus that infects bacteria. Like all viruses, phages are obligate intracellular parasites, devoid of protein synthesizing machinery and energy conversion systems.
Mutations are heritable changes in the genetic material that give rise to alternative forms of any gene. These alternate forms are called alleles. There are two broad types of mutations, those that affect the gene and those that affect whole chromosomes (
A tissue is a group of similar cells (together with associated cell products) specialized for the performance of a common function.
Alkaloids are classified according to the amino acid that provides both the nitrogen atom and the fundamental portion of the alkaloid skeleton, and these are discussed in turn.
Discoveries in molecular biology have allowed scientists to duplicate natural genetic transfer phenomena in the laboratory and to develop methods to introduce almost any type of genetic information into an organism.
Most insects? tough exoskeletons protect their bodies from predators and from drying out. however, some insects?including young insects, such as caterpillars - have soft bodies. they benefit by adding an extra layer of protective armor.
Horticulture may be described as the practice of growing plants in a relatively intensive manner. This contrasts with agriculture, which, in most Western European countries, relies on a high level of machinery use over an extensive area of land
Germplasm theory of Weismann was a very significant advancement in our understanding of heredity, since this was for the first time that a distinction between hereditary and environmental variations could be made on a sound basis.
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