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chloroplast

(Encyclopedia)chloroplast klōrˈəplăstˌ, klôrˈ– [key], a complex, discrete green structure, or organelle, contained in the cytoplasm of plant cells. Chloroplasts are reponsible for the green color of almost...

dry rot

(Encyclopedia)dry rot, fungus disease that attacks both softwood and hardwood timber. Destruction of the cellulose causes discoloration and eventual crumbling of the wood. This frequently results in the collapse of...

allergy

(Encyclopedia)allergy, hypersensitive reaction of the body tissues of certain individuals to certain substances that, in similar amounts and circumstances, are innocuous to other persons. Allergens, or allergy-caus...

cephalosporin

(Encyclopedia)cephalosporin sĕfˌəlōspôrˈĭn [key], any of a group of more than 20 antibiotics derived from species of fungi of the genus Cephalosporium and closely related chemically to penicillin. Cephalospo...

orchid

(Encyclopedia)CE5 Rose pogonia, Pogonia ophioglossoides, a member of the orchid family orchid, popular name for members of the Orchidaceae, a family of perennial herbs widely distributed in both hemispheres. Th...

Monera

(Encyclopedia)Monera, taxonomic kingdom that comprises the prokaryotes (bacteria and cyanobacteria). Prokaryotes are single-celled organisms that lack a membrane-bound nucleus and usually lack membrane-bound organe...

chitin

(Encyclopedia)chitin kītˈən [key], main constituent of the shells of arthropods. Chitin, a polysaccharide (see carbohydrate) analogous in chemical structure to cellulose, consists of units of a glucose derivativ...

humus

(Encyclopedia)humus hyo͞oˈməs [key], organic matter that has decayed to a relatively stable, amorphous state. It is an important biological constituent of fertile soil. Humus is formed by the decomposing action ...

disease

(Encyclopedia)disease, impairment of the normal state or functioning of the body as a whole or of any of its parts. Some diseases are acute, producing severe symptoms that terminate after a short time, e.g., pneumo...

hay fever

(Encyclopedia)hay fever, seasonal allergy causing inflammation of the mucous membranes of the nose and eyes. It is characterized by itching about the eyes and nose, sneezing, a profuse watery nasal discharge, and t...