Physiology, question

That is not to say continued research with pure isomers of such drugs should be hampered. Instead, many important pharmacological and physiological questions can be explored using such pure isomers. In addition, such investigations may enhance the therapeutic usefulness of the drug racemic mixture. 

A perennial physiological question concerning dinosaurs is whether they were capable of maintaining relatively uniform temperatures throughout their bodies (homeothermy nominally taken to be 2°C) via intrinsic mechanisms (endothermy). Thermoregulation in fact can be achieved by a variety of mechanisms. Even ectotherms... 

The study of biochemistry includes chapters on the four important families of biochemicals— carbohydrates, lipids, proteins, and nucleic acids— with an emphasis on the relationship between chemical stmcture and biological frmction for each. These chapters are followed by others on intermediary metabolism and human nutrition. In the discussion of all these topics we have emphasized physiological questions and applications where possible. 

The 11,12-oxido and 14,15-oxido analogs of leukotriene A4 were synthesized to help answer the question of whether these compounds might be biosynthesized from arachidonate by the 12- and 15-lipoxygenation pathways and serve as physiologic regulators. Hydrolysis products of the 14,15-oxide were later found to be formed in biological systems. 

It has been said that God created an organism especially adapted to help the biologist find an answer to every question about the physiology of living systems if this is so it must be concluded that pyridoxal phosphate was created to provide satisfaction and enlightenment to those enzymologists and chemists who enjoy pushing electrons, for no other coenzyme is involved in such a wide variety of reactions, in both enzyme and model systems, which can be reasonably interpreted in terms of the chemical properties of the coenzyme. Most of... 

In 1953, Bloch, together with the eminent organic chemist R. B. Woodward, proposed a new scheme (see figure, part b) for the cyclization of squalene. (Together with Fyodor Lynen, Bloch received the Nobel Prize in medicine or physiology in 1964 for his work.) The picture was nearly complete, but one crucial question remained How could isoprene be the intermediate in the... 

Very many other examples might be quoted, but these suffice to show that each of the classes of substances quoted has some common inherent characteristic quite apart from questions of volatility, solubility, or physiological action. 

In acidic solution at low pH, a carboxylic acid is completely undissociated and exists entirely as RCO2H- In basic solution at high pH, a carboxylic acid is completely dissociated and exists entirely as RC02 - Inside living cells, however, the pH is neither acidic nor basic but is instead buffered to nearly neutral pH—in humans, to pH = 7.3, a value often referred to as physiological pH. In what form, then, do carboxylic acids exist inside cells The question is an important one for understanding the acid catalysts so often found in biological reactions. 

The recent explosion in the discovery of new myosin genes has led to the idea that myosins from different classes probably co-exist in cells. This has raised the obvious question as to what functions these myosins subserve within cells. Up to now, only the genes have been cloned for many of the 35 unique myosins. But this is not a question that can be answered solely by cloning rather, it is absolutely imperative to biochemically characterize these proteins if we are to understand their physiological properties. One way to do this is to express the entire protein or parts of the proteins in bacteria, yeast, or insect cells, and to then purify and characterize... 

The physiologic LRG interaction actually involves at least five types of components ligand, receptor, intact G or G protein subunits (a and Py), GTP (which promotes LRG dissociation and activation), and GDP (which promotes LR dissociation from G but not G dissociation into its subunits). Little about the dynamics of these processes is known. The LRG states may be visualized, in shorthand, as a 3-dimensional array (Figure 1). A large number of questions concerning LRG states remain to be addressed ... 

Dietary studies, based on stable isotope values of animal tissues and foodstuffs, can be successful only insofar as the complexities of molecular metabolism manage to give rise to relatively simple relationships in what is measured. Many of these relationships have been explored, and have in part been described by observational regularities, and in part summarised by physiological or biochemical explanations. Some questions can and have now been clearly posed for example ... 

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