Babylon university
College of medicine
Department of microbiology
Assist. Prof. Dr. Ilham alsaedi
Metabolism of Microorganisms
Metabolism:-
Refer to the sum of the biochemical reactions required for energy generation and the use of energy to synthesize cell materials from small molecules in the environment.
Anabolism:-
Is the overall process by which cells synthesize molecules and structures. It also referred to as biosynthesis.
Catabolism:-
Is the overall chemical process in which cells break down large molecules into smaller ones catabolism is a process that generally results in the liberation of energy.
Metabolism contributes to the stability of a living cell while providing a dynamic pool of building blocks for synthesis reactions. In addition metabolism permits cells to extract energy for their life processes and to continue to grow and multiply.
Energy of metabolism: Many of the chemical reactions of metabolism are types of anabolism and anabolism generally requires an input of energy. In addition, an input of energy is generally required to begin the reactions of catabolism. Moreover, microorganisms require energy for such things as motion, for responses to environmental stimuli, and for reproductive processes. The storage form for microbial energy is the chemical compounds((Adenosine triphosphate (ATP))). When the energy is released from an ATP molecule, the molecule breakdown into((Adenosine diphosphate))(ADP).The breakdown of a single ATP molecule provides(10000) calories of energy for cellular work.
Cellular metabolism is regulated by the a availability of enzymes. These proteins ensure the proper, systematic interaction of those molecules necessary to build new cell materials other enzymes provides the catabolic process that result in a continuous supply of energy to carry out cell processes.
NAD (Nicotinamide Adinosin Dinucleotide):
Coenzyme commonly involved in energy-producing metabolism ,derived from the vitamin niacin. The basis for chemical transformations of energy usually involves oxidation/reduction reactions. For a biochemical to become oxidized, electrons must be removed by an oxidizing agent. The oxidizing agent is an electron acceptor that becomes reduced in the reaction. During the reaction, the oxidizing agent is converted to a reducing agent that can add its electrons to another chemical, thereby reducing it, and oxidizing it self.
The molecule that usually function as capled oxidation-reduction reactions in biological system is NAD and it is phosphorylated derivative, NADP.NAD or NADP can become alternately oxidized or reduced by the loss or gain of two electrons. The oxidized form of NAD is symbolized NAD; the reduced form isNADH2 or NADH+H+.
NAD is a derivative of ADP(NAD=ADP-ribose + Nicotinamide).
How is energy available to microorganisms for synthesizing ATP molecules?
Are energy-yielding reactions in which electrons are lost from substrate molecule. The molecule is said to be oxidized.
In a reduction reaction, electrons are added to a substrate molecule and the molecule is said to be reduced.
process. Oxidation and reduction reactions usually happen together, and the energy released is then captured in ATP.
Where does the energy for microbial metabolism come from?
The ultimate source of all energy on the earth is the sun. The sun´s energy on the earth is the sun. he sun´s energy is captured during the process of photosynthesis and is incorporated into carbohydrate molecules. The carbohydrate molecules. The carbohydrate molecules, such as glucose, sucrose, lactose, maltose and starch, are then utilized by living things as energy sources the energy is released from the carbohydrates during metabolism and used to form ATP molecules.
Glycolysis: Is multistep process in which one glucose molecule(contain six carbon atoms)is converted to numerous compounds through a metabolic pathway(such as Embden-Meyerhoff pathway)to yield two molecules of pyruvic acid(has three carbon atoms).
As a result of glycolysis four ATP molecules are produced. However, two ATP molecules were initially ((invested)) in pathway and the net gain is therefore two ATP molecules.
The two molecules of pyruvic acid then be utilized for ATP production through the reaction of Kreb´s cycle and electron transport to yield 36 ATP or they may be utilized in fermentation.
Fermentation:
Is a metabolic pathway that does not involve oxygen. In fermentation specific enzymes take the pyruvic acid molecules and convert them to acids, alcohol and other end products. This pathway commonly occurring in yeast in anaerobic conditions, by the help of specific enzymes.
This process is the basis for the fermentation in destroy that produces beer, wine, spirits and other alcohol. The fermentation can also yield various acids such as acetic acid, butyric acid, and lactic acid, depending upon which enzyme is present and which organism is producing the enzyme.
Fermentation is a way to obtain the two molecules of ATP per molecule of glucose metabolized through glycolysis. If oxygen were present, fermentation would probly not occur and the pyruvic acid would be utilized in Krebs cycle.
*Roles of metabolism in biosynthesis of growth:-
The microbial growth requires the polymerization of biochemical building blocks into; proteins, nucleic acids, polysaccharide and lipids which depend on the presence of ATP and focal metabolites.