Biochemicals machinery

Nonoxidizing Antimicrobials. Nonoxidizing antimicrobials usually control growths by one of two mechanisms. In one, microbes are inhibited or killed as a result of damage to the ceU membrane. In the other, microbial death results from damage to the biochemical machinery involved in energy production or energy utilization. 

These extensive alterations in cell structure and the biochemical machinery are indicative of entry into an ametabolic condition. In this condition damage from free radicals is potentially decreased, certainly the loss of chlorophyll and chloroplast structure removes a major source of free radical generation. About 50% of the extremely desiccation tolerant monocots exhibit extensive loss of chlorophyll and ultrastructural organisation when desiccated. Dicots, ferns and bryophytes retain most of their chlorophyll and exhibit small changes in structure when dry (see Gaff,... 

Historically, this lack of competition is probably responsible for the flies total dependency on the cactus The flies somehow lost the biochemical machinery needed for conversion of common plant steroids into those steroids they require. The loss went unnoticed, because the cactus provided an assured source of steroids the flies were still able to utilize. However, no other available plants provide these unusual steroids, so they must now consume senita cactus to survive. 

An enzyme is a protein that speeds up a biochemical reaction without itself experiencing any overall change. In chemical language, such a compound is called a catalyst and is said to catalyze a reaction. Chemists employ a variety of compounds as laboratory catalysts, and many industrial chemical processes would be impracticably slow without catalysis. An automobile s catalytic converter makes use of a metal catalyst to accelerate conversion of toxic carbon monoxide in the exhaust to carbon dioxide. Similarly, our bodies biochemical machinery effects thousands of different reactions that would not proceed without enzymatic catalysis. Some enzymes are exquisitely specific, catalyzing only one particular reaction of a single compound. Many others have much less exacting requirements and consequently exhibit broader effects. Specific or nonspecific, enzymes can make reactions go many millions of times faster than they would without catalysis. 

More than most of us can hope for, Williams life was also filled with extraordinary gifts and accomplishments. For over 20 years he and his co-workers worked to discover, isolate, characterize and synthesize the substance he named pantothenic acid, an essential cog in the biochemical machinery of all living things. He also first concentrated and named folic acid, another B vitamin. As founder and director of the Clayton Foundation Biochemical Institute at the University of Texas at Austin from 1940 to 1963, he and his colleagues made many other notable contributions to nutrition and biochemistry. 

The virus, however, does not contain any of the cellular components necessary to replicate itself or synthesize proteins and other macromolecules that is, the virus lacks ribosomes, endoplasmic reticulum, and so on.18 The virus contains only the genetic code (viral genome) that will produce additional viruses. To replicate itself, the virus must rely on the biochemical machinery of the host cell.95 In essence, the virus invades the host cell, takes control of the cell s metabolic function, and uses the host cell s macromolecu-lar-synthesizing apparatus to crank out new viruses. Specific steps in the viral replication process are described in the next section. 

The relative solubility of materials is relevant to most of the subjects covered in this book. The biochemical "machinery" used for digestion, absorption, and trans-port of nutrients throughout the body depends on whether the nutrients are water soluble or fat soluble. Relative solubilities are also crucial to the function, composition, and architecture of cells and their surrounding membranes. 

The lipids of the diet include TGs, phospholipids, cholesteryl esters, cholesterol, and the fat-scivble vitamins. These nutrients require special types of biochemical machinery to facilitate their assimilation and distributicrt within the body. The biochemical apparatus used includes bile salts, apolipoprotcins, serum albumin, and vitamin-binding proteins. Apolipopnoteins are the primary subject of this section. The term apolipoprotain is used when referrmg only to the protein, whereas the term lipoprotein refers to the complex of apolipoprotein and lipid. 

The properties of other proteins — such as soybean protein, egg protein, and meat protein — as well as their food sources (matrices), are major topics in food science leather than dwell on this subject, we will turn to some of the features of dietary protein, after digestion and acquisition of their component amino acids by the body. The role of dietary protein in allowing growth and the maintenance of health will be detailed, though the biochemical machinery (ribosomes, tRNAs, aminoacyl tRN A synthases) used for the assembly of amino acids into proteins will not be described. 

Histamine is both a local hormone and a neurotransmitter in the central nervous system. It is synthesized in neurons and mast cells. There are Hi, H2, and H3 receptors in the central nervous system, but they differ in their localization, biochemical machinery, functions, and affinities for histamine they are particularly important in maintaining a state of arousal or awareness (1). 

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