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Basic Energy Concepts
Types of Catabolism
Catabolism of Fats
Catabolism of Proteins
Summary of Catabolism
Synthesis of Monomers
©2000 Timothy Paustian, University of Wisconsin-Madison
Once a microbe collects a needed the element from its surroundings, it is converted into organic compounds that the cell requires. Some of these compounds are useful to the cell as is, to carry out necessary functions. Others serve as monomers for the synthesis of macromolecular biopolymers (say that five times fast). These biopolymers (DNA, RNA, protein, lipids, ribosomes) either serve a structural role, carry out a necessary cellular function or both.
Many microbes are capable of synthesizing everything they need from just one compound (CO2 or glucose). Others have less able biosynthetic machinery and depend upon collecting ready made compounds that they find in the environment. The biosynthetic capabilities of a microbe are often shaped by its habitat. Streptococcus mutans has its major residence in our mouths and depends upon us to provide many nutrients including glucose (an energy source) ; amino acids, vitamins and fatty acids. On the other end of the spectrum, some Pseudomonas species that live in the soil are capable of generating energy and synthesizing everything they need from crude oil.
Most cells will keep a close eye on their environment and scavenge needed biomolecules instead of synthesizing them. If they find proline (an amino acid) in the environment, they will take it up and use it. Most will also shut off the biosynthetic machinery that functions to make proline so as not to waste energy. Biosynthesis take energy and the cell strictly controls biosynthetic genes and the proteins they code for. This control of biosynthetic activity is called regulation, which is covered in another section of the text book. [not open for business yet.]
In this section we look at the incorporation of some of the more important elements into cell material and the synthesis of a few critical monomers. The goal is to give the reader a general idea of the methods used to convert raw materials into needed monomers.
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