Metabolism: all the physical and chemical processes in the body that convert or use "energy," such as breathing, circulating blood, controlling body temperature, contracting muscles, digesting food and nutrients, eliminating waste, and functioning of the brain and nerves. (MedlinePlus)

All chemical changes that take place in a cell through which energy and basic components are provided for essential processes, including the "synthesis" of new "molecules" and the breakdown and removal of others. (NCIt) Describes the many chemical processes in all living things. (Hunt, 55) Verb - ‘metabolize.’ Adjective - ‘metabolic.' Also referred to as ‘metabolic processes.'

Anabolism: the “synthesis” of cellular molecules and "macromolecules." (Brooker, 69) Entails the construction of complex "organic" molecules from simpler "precursors" (NCIt) Adjective - ‘anabolic.”

Anaerobic Metabolism: a mode of energy conversion defined by lack of sufficient "oxygen" to convert "fat" and “glucose” into usable body fuel. When the body is pushed so fast and so hard that the working muscles’ demand for fresh oxygen outstrips the circulating blood’s ability to deliver it, the muscles begin to burn fuel inefficiently. (Ratey, 275)

Fermentation: a process which occurs in the absence of oxygen in which small organic molecules are produced from larger ones. Fermentation by “microorganisms” has been exploited by humans for many thousands of years. The ancient Egyptians, for example, used ‘yeast’ to make beer. (Indge, 108) The breakdown of organic molecules to produce energy without any “oxidation.” The breakdown of glucose to “lactic acid” or “ethanol” are examples. (Brooker, 145) No oxygen required. Occurs in the “cytosol.” Two “ATP’s” produced. Waste includes lactic acid ('lactate') and ethanol. (Norman, 6/23/09) With modern techniques of biotechnology, fermentations by microorganisms have been used to produce a variety of different products, ranging from foodstuffs, such as yogurt and cheese, to drugs such as the "antibiotic"  'penicillin.' In animals, in the absence of oxygen, glucose is converted to (lactic acid.) This is sometimes called “anaerobic respiration,” but it is an example of a fermentation. (Indge, 108)

Catabolism: involves the breakdown of complex substances into simpler molecules. (NCIt) Must be employed in order to break down any “organic” “macromolecule” to a useful substance for cells. Water is often a key participant. (Norman, 33) Catabolic reactions break apart “chemical bonds” that hold large molecular “compounds” together. (Norman, 6/11/09) Adjective - ‘catabolic.’

Metabolic Pathway: a series of steps involved in metabolism. A specific “enzyme” is responsible for speeding up each step. Some pathways involve the breakdown of molecules into smaller components. Other pathways are involved in the synthesis of cellular molecules and macromolecules. (Brooker, 69)

Primary Metabolism: the synthesis and breakdown of molecules and macromolecules that are found in all forms of life and are essential for cell structure and function. (Brooker, 145)

Secondary Metabolism: involves the synthesis of molecules that are not essential for cell structure and growth. (Brooker, 145)

Secondary Metabolites: molecules not essential for cell structure and growth. Not usually required for survival. Commonly made in "plants," “bacteria,” and “fungi.” Many secondary metabolites taste bad and may prevent an animal from eating the plant. May produce a strong smell or bright color that attracts or repels other organisms. For example, the scent from a rose attracts insects that aid in “pollination.” Iincludes spices used in cooking and antibiotics (that inhibit the growth of “pathogenic”  “microorganisms") used to treat diseases. (Brooker, 145)

Alkaloids: one of a diverse group of “nitrogen" containing substances that are produced by plants and have potent effects on body function (OxfordMed). Group of organic chemicals containing nitrogen and other elements that have pronounced effects on the body. (Bynum, 292) Structurally related molecules that all contain nitrogen. Commonly made in plant species and occasionally in "fungi" and shellfish. (Brooker, 146) Caffeine, "nicotine,"  "morphine,"  "cocaine,"  "heroin,"  and "codeine" are examples of alkaloids that influence the physiology and behavior of humans. (Brooker, 659)

Phenolic Compounds: a category of secondary metabolites. "Antioxidants" that have intense flavors and bright colors. (Brooker, 146)

Flavonoids: phenolic compounds produced by many plant species. Create a variety of flavors and smells. The flavors of chocolate and vanilla largely come from a mixture of flavonoid molecules. Have remarkable antioxidant properties that prevent the formation of damaging ‘free radicals.’ (Brooker, 146) Another role of flavonoids is ‘pigmentation.’ (Pigmentation) produces the red, purple, and blue colors of many flowers, fruits, and vegetables.

Lignins: phenolic compounds found in plant “cell walls.” Strengthen plant cells and enable a plant to better withstand the rigors of environmental stress. Make up one-third to one-quarter of the weight of dry wood. To make paper, which is much more malleable than wood, the lignin is removed. (Brooker, 146)

Tannins: phenolic compounds that combine with the protein of animal skins to form leather. This process, known as ‘tanning,’ also imparts a tan color to animal skins. Found in many plant species and typically act as a deterrent to animals, either because of a bitter taste or due to toxic effects. Found abundantly in grape skins and play a key role in the flavor of red wine. Aging breaks down tannins, making the wine less bitter. (Brooker, 146)

Polyketides: a category of secondary metabolites. Produced by "bacteria," fungi, plants, insects, and others. Often highly "toxic" to other organisms. The polyketide known as ‘streptomycin’ is made by a solid bacterium that is secreted and taken up by other species, where it disrupts “protein synthesis” and thereby inhibits their growth. In this way, it is able to kill or inhibit the growth of other species in its vicinity - an advantage because other species may be using limited resources that the bacterium could use for its own growth. (Other) examples include ‘erythromycin’ and ‘tetracycline.’ Recently, researchers have discovered that certain polyketides inhibit the growth of "cancer" cells. The production and sale of polyketides to treat and prevent diseases and as pesticides constitutes an enormous industry, with annual sales in the U.S. at over $20 billion. (Brooker, 147-148)

Terpenoids: a category of secondary metabolites. Molecules with intense smells and color. Over 25,000 have been identified, more than any other family of naturally occurring products. Often impart an intense flavor to plant tissues. Many of the spices used in cooking are rich in different types of terpenoids. Examples include cinnamon, fennel, cloves, cumin, caraway, and tarragon. Found in many traditional herbal remedies. (Brooker, 147)