Thursday, March 22, 2007

Taking Xanax Before Waxing



Metabolism Total chemical reactions that occur in the cell. The flow of energy and involvement of enzymes make it possible. Is given in two parts:

-Catabolism: large, complex molecules are broken down to simpler molecules with the release of energy. Part of this energy can be trapped and used for anabolism, the rest is released as heat.


-Anabolism: Synthesis of complex molecules from simple molecules with energy use.

Power: is defined as the ability to produce work. In the cells can perform 3 types of work:


- Chemical, biological synthesis of complex molecules from simple precursors
- Transport: molecules and ions are transported through the plasma membrane against concentration gradient (internalization of nutrients, waste disposal and maintenance of ion balance.
- Mechanical

Energy used mainly by photosynthetic organisms is sunlight that is converted to chemical energy to use atmospheric CO2 as a carbon source for production of glucose and other molecules.


complex molecules produced by these bodies serve as a carbon source to chemoheterotrophs using the O2 as electron acceptor when oxidizing glucose and other organic molecules to reduce CO2 and release a lot of energy. This CO2 can be reincorporated again as a carbon source for photosynthesis. With this, there is a flow of ecosystem carbon and energy.

The cell must have a system of highly efficient energy transfer, as a practical use of available energy through ATP (adenosine triphosphate) that losing a phosphate group releases energy required to produce work.


Then by processes such as photosynthesis, aerobic respiration, fermentation and others is resynthesized.

To understand the role of ATP: There are mainly 2 types of chemical reactions:

- exergonic: produce energy, ΔG ° is
negative - endergonic: require energy, ΔG ° is positive

endergonic reactions are not efficient without energy, ATP is a highly energetic molecule (ΔG ° = -7.3 kcal / mol) orthophosphate that losing is a highly exergonic reaction that provides energy for the endergonic reaction is carried out.

Bacterial Metabolism: Bacterial metabolism can be divided into 3 stages:


1.Moléculas complex is hydrolyzed to its constituents. The reactions do not generate much energy.


2.Moléculas obtained are degraded to simpler molecules: acetyl CoA, pyruvate and intermediates of tricarboxylic acid cycle. Aerobic or anaerobically and produces ATP, NADH and / or FADH2.


3.Ciclo tricarboxylic acid: molecules are oxidized to CO2 with the production of ATP, NADH and FADH2. Aerobically and produces a lot of energy, much of the ATP produced is derived from the oxidation of NADH and FADH2.

metabolic pathways consist of reactions catalyzed by enzymes arranged so that the product of one reaction serves as substrate for the other. The existence of several common catabolic pathways of metabolism increases efficiency.


Energy is released as a result of redox reactions in the catabolism and is then stored and transported in the most common compounds with high-energy phosphate bonds and then serve as intermediates in the conversion of energy into useful work. The compound of high-energy phosphate is the most important adenosine triphosphate (ATP).


For the metabolism of carbohydrates, bacteria have 3 main ways:

-

glycolysis or Embden-Meyerhof-Way
the pentose phosphate pathway
-Enter-Doudoroff pathway


The glycolytic pathway: for every molecule of glucose to produce 4 molecules of ATP, but consumed 2, thus producing net 2 ATP per molecule of glucose. In the remaining tracks only produces 1 ATP per molecule of glucose.


bacteria in the redox systems include two major processes:


-Fermentation: acceptors and electron donors are organic molecules. Partial oxidation, is released only part of the energy, energy efficiency is low. Different types.


-Breathing: exogenous final acceptor (O2 in aerobic respiration and anaerobic respiration inorganic compound). The substrate is completely oxidized to CO2 and water.


Fermentations: In the absence of O2, NADH is oxidized by the electron transport chain because there is no available external acceptors. Many microbes have solved this problem by using pyruvate or some of its derivatives as electron acceptors and H + in the reoxidation of Nahda, leading to production of more ATP, but phosphorylation of substrate.


- Alcoholic fermentation: fermentation of sugars to ethanol and CO2.

- Lactic Fermentation: conversion of pyruvate to lactate is separated into two groups:


a. Fermenters homolactic: Use the glycolytic pathway and directly reduce most of the pyruvate to lactate with lactate dehydrogenase

b. Heterolactic fermenters, producing lactate as well as ethanol and CO2 via fosfocetolasa


- Formic Acid Fermentation: is converted to H2 and CO2 by Formica hidrogenilasa:

a. Mixed acid fermentation: production of ethanol and a complex mixture of acids, particularly acetic, lactic, succinic, and formic acid. (E.coli, Salmonella, Proteus)


b. Butanediol fermentation: pyruvate is converted to acetoin which is then reduced to 2.3 butanediol with NADH. It produces a large amount of ethanol with small amounts of acid.


BACTERIAL GROWTH:


GROWTH: Increase in cellular constituents. In the case of microorganisms growth involves an increase in the number of cells to reproduce by processes such as budding or binary fission.


growth cycle are matched based on the analysis of the growth curve of a microbial culture.


Microorganisms grown in a liquid medium in a closed system is not supplied with fresh medium during incubation, so that the concentration of nutrients decreases and increases waste.


growth can be graphed as the logarithm of cell number versus the incubation time. Resulting in a curve of 4 phases:



PHASE LAG:


Microorganisms are introduced to a fresh medium, this is not an immediate increase in the number of cells or cell mass. No cell division as the cell is synthesizing new components, that due to several reasons: growing old or damaged, different medium.


After this recovery phase synthesis and the cells are in top shape to replicate their DNA, to grow in cell mass and divide. This phase can vary considerably depending on the condition of the inoculated bacteria and the nature of the medium used.

exponential growth phase OR LOG:

microorganisms found in the maximum rate of growth and division may be determined by: genetic potential, the nature of the medium and growth conditions.

The growth rate is constant, divide and double in number at regular intervals. Because each cell divides at a slightly different growth curve increases gradually rather than jumping.


STATIONARY PHASE:

growth ceases and the curve becomes a horizontal line. The final size of the population depends on: availability of nutrients and other factors as the type of this microorganism.

The total number of viable microorganisms remains constant, there is a balance between cell division and cell death or because people simply cease division and remains metabolically active. It reaches this stage by: nutrient limitation, oxygen depletion, toxic waste accumulation.


PHASE DEATH:

adverse changes in the growth environment leads to decrease the amount of viable cells. The death phase as the exponential phase of growth is logarithmic, a constant proportion of cells die every hour.

Factors affecting growth:


To obtain energy and synthesize new cellular components, organisms must have a nutrient supplement.

Composition about 95% of the dry weight consists of carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, potassium, calcium, magnesium and iron
These are called macroelements or macronutrients.


Macroelements: components of carbohydrates, lipids, proteins and nucleic acids and some exist in the cell in the form of cations and play a series of important papers (enzyme cofactors, cytochromes, electron acceptor)

The
microorganisms also require microelements or trace elements, these consist of: manganese, cobalt, zinc, molybdenum, nickel and copper.


These requirements are usually added contaminants in water, glass and components in the middle.


Classification of Microorganisms in the mode of energy production:


Power Sources:


- phototrophs:
light for photosynthesis - chemotrophs: oxidation of organic molecules and inorganic.


Hydrogen and electrons:


- CHEMOLITHOTROPHY: reduction of inorganic
- chemoorganotrophy: reduction of organic substances