Section 6: GLOSSARY 



absorbancy: Sjoionymous with optical density; 

 equal to -logio T. where T^transmittancy; 

 molar absorbancy index or extinction coeffi- 

 cient is the absorbancy of a 1-molar solution 

 through a 1-cm. light path. 



accessory glands: In insects and other inverte- 

 brates; secretory organs associated with re- 

 productive function. 



adductor muscle: In bivalve mollusks, a muscle 

 that closes the valves of the shell. 



albuminous or albumen gland: In the higher 

 gastropod mollusks; a part of the female re- 

 productive system, it secretes an albuminous 

 material around the egg before the shell is 

 added. The albuminous material serves as 

 food for the developing embryo. 



antimycin A: An antibiotic isolated from Strep- 

 tomyces spp.; inhibits the oxidation of suc- 

 cinate at the level of the Slater factor. 



ascorbate: The salt of ascorbic acid; a reduc- 

 ing agent used to reduce cytochrome c. 



axoplasm: The cytoplasm of a nerve fiber. 



Barcroft respirometer: A differential respirom- 

 eter consisting of two flasks connected to a 

 manometer. In this closed system one flask 

 serves as a thermobarometer; the other, as 

 a tissue chamber. As the tissue consumes 

 oxygen and produces carbon dioxide, which is 

 absorbed by alkali, both volume and pressure 

 in the respiration chamber change. The differ- 

 ence in pressure between the two flasks is 

 measured on the column of the manometer. 



brachyuran: Pertaining to the true crabs or 

 Brachyura. 



branchial or respiratory tree: In sea cucumbers 

 (Echinodermata), consists of two long, branch- 

 ing tubes that arise from the cloaca and ter- 

 minate blindly in the anterior portion of the 

 body cavity; functions in respiration and ex- 

 cretion. 



buccal mass: In mollusks, exclusive of bivalves; 

 a more or less compact mass of muscles and 

 cartilage that supports and operates the radula. 



catalase: An enzyme that catalyzes the conver- 



sion of hydrogen peroxide to water and mole- 

 cular oxygen. 



citric acid cycle: Another name for tricarboxy- 

 lic acid cycle or Krebs cycle; the primary 

 mechanism by which the aerobic oxidation of 

 metabolic intermediates to carbon dioxide and 

 water takes place. 



clitellate: Indicative of the fact that an annelid, 

 such as an earthworm or a leech, is sexually 

 mature and bears a clitellum. 



clitellum: A glandular thickened region that 

 secretes a capsule for eggs and may assist in 

 attachment during copulation. 



collagenous: Pertaining to collagen, a protein 

 that is found in large amounts in connective 

 tissue. 



columella muscle: In gastropod mollusks; is 

 attached to the columella (central column) 

 and serves to retract the body of the animal 

 into the shell. 



corpora allata: In insects; glands that secrete 

 a hormone (juvenile hormone) capable of pre- 

 venting metamorphosis while permitting 

 larval molting; also involved in the control 

 of reproduction. 



coxal muscles: In insects, crustaceans, and 

 other arthropods; muscles of the coxa, which 

 is the first segment of a leg and which effects 

 the articulation of the leg with the body. 



cytochrome c: A heme protein, the position of 

 which in the terminal electron transport chain 

 is such that it may be reduced from the ferric 

 (Fe+++) to the ferrous (Fe"*"*") form by cyto- 

 chrome Cj, cj^ochrome b, flavoproteins, or 

 certain added reducing agents; also may be 

 oxidized by cj^ochrome oxidase or by certain 

 added oxidizing agents. 



cj^ochrome oxidase (cytochrome (23): A heme 

 protein that oxidizes cytochrome c and reduces 

 molecular oxygen; its activity is inhibited by 

 cyanide, azide, and carbon monoxide, the in- 

 hibition by carbon monoxide being light re- 

 versible. 



cytochrome system: A group of respiratory 



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