Life: building blocks chemical reactions

Recent work suggests that there may have been a period in Europa s history when an extreme greenhouse effect led to temperatures which would have sufficed for reactions necessary for chemical evolution. According to this (unproven) hypothesis, building blocks for biomolecules or even primitive life forms could have existed. The authors assume that there is a high probability that bioelements could have been delivered by comets (Chyba and Phillips, 2002). 

Proteins are a diverse family of large molecules composed of 20 amino acid building blocks. They are an integral part of our diet. Our genetic blueprint codes for proteins produced inside our cells that promote the chemical reactions of life, protect us from infection, act as communication devices, facilitate transport of molecules and ions, mediate movement, and provide structure for our cells and bodies. 

A large number of successful experimental studies which tried to work out plausible chemical scenarios for the origin of life have been conducted in the past (Mason, 1991). A sketch of a possible sequence of events in prebiotic evolution is shown in Figure 3. Most of the building blocks of present day biomolecules are available from different prebiotic sources, from extraterrestrial origins as well as from processes taking place in the primordial atmosphere or near hot vents in deep oceans. Condensation reactions and polymerization reactions formed non-in-structed polymers, for example random oligopeptides of the protenoid type (Fox... 

The suggestion that the molecular building blocks of life could be formed in space is intriguing since such regions would seem to be rather unlikely places for the development of chemistry. The ISM is cold (temperatures of 10-30 K) and "empty" with pressures of less than 10 2 torr such that the probability for a collision between two compounds is low and, at such low temperatures, the "reaction rate" would be expected to be very low (hence in most industrial chemistry the reactants are heated to increase their reactivity). Nevertheless the detection of such molecules within the ISM makes it clear that these are chemically active zones. The solution to this apparent paradox is that the chemistry in the ISM is somewhat different from the conventional chemistry we observe on Earth, much of it being induced by radiation. The ISM contains several different sources of radiation, namely ... 

Distinguish between the reactions that cells use in the presence and in the absence of oxygen to extract energy from fuel molecules. Explain how a small number of biochemical building blocks can be used to make the extraordinary variety of molecules needed to perform life s chemical functions. 

The atom is the basic building block of matter. The model of the atom is a positively charged nucleus and surrounding negative electrons. The chemical behavior of an atom depends on the numbers of these electrons. Most atoms exist as part of molecules. All life on earth depends on molecular processes. Most of these processes need a molecular catalyst to speed up chemical reactions taking place at body temperature. 

Simplify the complex chemical reactions that take place everywhere in our lives with The Handy Clicmislry Answer Book In an engaging, easy-to-follow, queslion-and-answer format, chemical concepts are tackled and explained in plain English (with a little help from formulas, photos, and illustrations) to help enlighten you about the building blocks of life and the universe. The secret life of atoms, how polar bears aren t ac tually white, why oil and water don t mix, and much, much more are revealed and explained. 

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