Some basic terminologies are brushed through in this section just for reminder’s sake.
The term metabolism describes the many reactions in which organic compounds are synthesized and degraded and useful energy is extracted, stored and used.
The study of the changes in energy during metabolic reactions is called bioenergetics.
The basic thermodynamic principles that apply to energy flow also apply to biochemistry. Thermodynamic considerations can tell us if a reaction is favored, but does not tell us how quickly a reaction will occur. The rates of the normally slow reactions are accelerated by enzymes so much so that enzyme-catalyzed reactions can be up to ×1017 greater than the rate of corresponding unanalyzed reactions!
An enzyme and a small molecule will collide one million times per second. Under these conditions, many enzyme-catalyzed reactions could be achieved if only 1 in about 1000 collisions result in a reaction.
Much of what we now know of biochemistry is attributed to the study of viruses. They are subcellular and consist of a nucleic acid molecule surrounded by a protein coat. Virus nucleic acid can contain as few as three genes or as many as several hundred. Despite their biological importance, viruses are not cells because they cannot carry out independent metabolic reactions; they multiply by hijacking the reproductive machinery of a host cell, making it form new viruses, so they’re genetic parasites.
That is all. Next chapter, water. “We made from water every living thing.” Quran, 21:30.