Chapter 07 - Bacterial Metabolism Flashcards
What metabolic/biochemical characteristics of bacteria are used identify microbes and understand what pathogens do in a host?
- Ability to ferment
- Ability to grow in an anaerobic environment
- Ability to use different carbon sources
- Ability to produce specific intermediate or waste products
These pathways are related to how microbes acquire their carbon, energy, and electrons towards the production of ATP
What is Matabolism?
All chemical reactions in a cell, but can be divided into two types of pathways.
Catabolic Rxn (Break Down) Anabolic Rxn (Build up)
Explain a Catabolic Rxn
“Break down reactions” or digestion
A metabolic pathway that is involved in the process of acquiring energy sources and converting the E into a usable form for the cell (ATP). Produce ATP that the cell can use to build complexity and perform necessary cellular functions.
Examples:
>Photosynthesis
>Cellular respiration
Explain a Anabolic Rxn
A metabolic pathway involved in building complexity within a cell or organism, which requires E input
Examples: >Building macromolecules >Cell division >Cell transport >Any kind of cellular, chemical, or mechanical work
What are the physical laws that govern hoe energy how energy works?
Law of Thermodynamics. All Biological entities are subjected to these laws
What is the 1st Laws of Thermodynamics?
Energy is not created or destroyed, but can be converted from one form to another
Catabolism is related to the first law because Converting E from organic molecules into E in ATP
What is the 2nd Laws of Thermodynamics?
The universe favors disorder (entropy), and the natural tendency of energy is to disperse
Anabolism is related to the second law
because to build complexity, an energy source is needed to overcome entropy.
What is Entropy?
The degree of disorder or randomness in the system.
The two sources of energy for living things are…?
- The Sun
2. Eating other things that contain electrons in the molecules in organic compounds
What rxn relates to the movement of electrons?
Oxidation/Reduction Rxns
a.k.a. Redox Rxns
How do catalyst influence metabolism?
Chemical reactions work faster with a catalyst.
Enzymes can make reactions occur at a faster rate
The presence of the lack of a required enzyme effect metabolism?
For an organism to be able to metabolize, it requires that certain enzymes be present.
If the required enzyme is absent:
- The organism may not be able to used a particular organic molecule as an energy source
- The organism may lack pathways that other organisms have
Things to remember when considering catabolic reactions…
> The purpose: create ATP that can be used by the cell
Energy in ATP comes from the energy found in organic compounds, such as sugars, proteins, and lipids
The organic compounds must be broken up to release the energy
Much of the energy is related to electrons in the organic material
Focus on carbon, electrons, and energy
Define Cellular Respiration
Production of ATP primarily through the removal of electrons (donated by hydrogens) from glucose
Examples:
Production of ATP primarily through the removal of electrons (donated by hydrogens) from glucose processed through an electron transport chain
Electron Transport Chain
Movement of electrons release E from compounds
That E is used to make a lot of ATP during oxidative phosphorylation
Oxidative Phosphorylation
The process in which ATP is formed as a result of the transfer of electrons from NADH or FADH 2 to oxygen by a series of electron carriers. This process, which takes place in mitochondria, is the major source of ATP in aerobic organisms
Areobic Respiration
A form of cellular respiration that uses oxygen as the final electron acceptors. This process is used by humans and nearly identical to the process used by many microbes.
Examples:
Glycolysis, TCA cycle, OxPhos
Anaerobic Respiration
Simular to aerobic respiration but does not use oxygen as the final electron acceptor. Depending on the organism other compounds are used as an electron acceptor.
Example:
NO3-
Fe3+
SO42-
Examples:
Glycolysis, TCA cycle, OxPhos
Overview of Glycolysis
>Usually shown to begin with glucose (6C), but can be different organic compounds (carbohydrates, amino acids, lipids)
>A small amount of ATP is produced
>A few electrons are collected for ETC
>Two pyruvate (3C) molecules are formed
>These molecules transfer to TCA
>None of the carbon from glucose is lostOverview of Tricarboxylic acid cycle
TCA
> Pyruvate from glycolysis enters TCA
The first reaction removes one carbon as CO2
>Additional reactions in TCA remove the other carbons
>All C from glucose is lost as CO2
As the organic compounds are cycled through, many electrons are removed and sent to ETC
Overview of Oxidative Phosphorylation
OxPhos encompasses two pathways
>Electron transport chain
>Chemiosmosis
Electrons from glycolysis and TCA (carried by NAD and FAD) transfer electrons to complexes in membrane
>This releases energy that membrane proteins use to pump protons across the membrane
>Creates a concentration gradient (more protons outside)
>Electrons eventually put onto final acceptors
Protons move back into the cell through ATP synthase
>Enzyme that makes ATP
The Process of Fermentation**
> Different from aerobic or anaerobic respiration, because TCA and OxPhos do not occur
Glycolysis does occur, so the only ATP made in fermentation is the little bit from glycolysis
Fermenting organisms still need a final electron acceptor, because some were collected in glycolysis
>Pyruvate, the end product of glycolysis, or a derivative of pyruvate accepts the electrons and is released
Different organisms have different fermentative pathways, so analysis of waste products can be used to identify microbes
Overview of Fermentation
> Multiple routes
All products derived from pyruvate
Products can be used for identification
These “arms” are used to get rid of electrons
The Process of Anabolism
Anabolic reactions are those related to biosynthesis
>Building larger, complex compounds using smaller molecules
>The energy to do this comes from the ATP generated through catabolism
The “building blocks” used to build complex molecules are called precursor metabolites
>Precursor metabolites are formed during catabolic reactions (degrading complex molecules)
>Precursor metabolites form the “carbon skeleton” of organic compounds
Anabolism Health Care Relevance
>Cell division and population expansion >Production of toxins >Quorum sensing >Biofilms >Antibiotics >Medicines >Normal flora
