Being structurally composed of one or more cells, which are the basic units of life. Yet within a cell, there seems to be the same behaviors that define life:
- Regulation of the internal environment to maintain a constant state;
- Organization: Don't most cells have organs?
- Growth ~ not sure about this one.
- Adaption ~ Think this is accurate, but I'm not well versed in cellular biology at all.
- Response to stimuli. Cells interact with external whatnots.
- Reproduction - Cells do this, at least many of them.
Most of what lead me to this question came from chapter 5 of Spontaneous Healing by Andrew Weil, M.D.. I'll type the parts relevant to the discussion below - in case he's wrong and I'm basing my thoughts on wrong information. bold sections indicate my interjection
DNA takes the same form in all organisms, from human beings to viruses - an enormous molecule with a double-helix structure made up of two chains of sugar molecules, with "rungs" linking the two chains. The rungs form between complementary pairs of nitrogen-containing subunits 'nucelotides', whose specific sequences differentiate the DNA of one organism from that of another. Only four different nucelotides occur in DNA; they are the "letters" of a genetic code spelling out "words" of information that direct the construction and operation of all forms of life. The so-called Central Dogma of modern molecular biology states that DNA replicates itself in order to pass its genetic information on from one cell to another and from one generation to the next reproduction; DNA also transcribes its information into another macromelecule, RNA, that can travel out of the cell nucleus; RNA, in turn, transslates this information into the manufacture of specific proteins that determine the structure and function of organisms. regulation? These three processes - the replication, transcription, and translation of genetic information - are the most basic processes of life. They are also amazingly intricate and risky, because there are so many points at which things can go wrong.
Snipped for relevance.
Therefore, sophisticated mechanisms have evolved for the repair of this molecule in order to assure nearly error-free transmission of genetic information from one generation to the next, even in the simplest forms of life. organization, regulation, reproduction - evidence of response to stimuli?
All of the mechanics of replication, transcription, and translation are directed by a special class of proteins called enzymes. A great deal of the genetic code specifies the manufacture of enzyme molecules, which, in turn, oversee the chemical reactions that develop the genetic code into biological reality. evidence of intelligence?
In practical terms, they (enzymes) function as ingenious machines that alter the substrate molecules: cutting them apart, putting them back together, snipping particular pieces off them, adding others back, all with astonishing precision and speed.
Therefore, polymerase I actually proofreads its own work, editing mistakes as it directs the synthesis of new copies of DNA.
He goes on to talk about plasma membranes, which seem to be how cells interact with the "outside" world..