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46 Cards in this Set
- Front
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Microbial Nutrition: Nutrition!
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Process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities.
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Essential Nutrients
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Must be provided to an organism * Two essential nutrients: 1) Macronutrients 2) Micronutrients |
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Macronutrients
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* Required in large quantities; play principle roles in cell structure and metabolism. * Proteins, carbohydrates- large part of you! |
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Micronutrients (trace elements)
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* Required in small amounts; involved in enzyme function and maintenance of protein structure - Manganese, zinc, nickel -vitamins & minerals. |
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Nutrients: Organic Nutrients |
- Contain carbon and hydrogen atoms and are usually the products of living things * Methane (CH4), carbohydrates, lipids, proteins, and nucleic acids. |
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Nutrients: Inorganic Nutrients |
- Atom or molecule that contains a combination of atoms other than carbon and hydrogen * Metals and salts (magnesium sulfate, ferric, nitrate, sodium phosphate) * gases (oxygen, carbon dioxide) and water. |
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Chemical Analysis of Cell Contents
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* 70% water * Proteins * 96% of cell is composed of 6 elements SCHNOP! Carbon, Hydrogen, Oxygen, Phosphorous, Sulfur, Nitrogen. CO2, H2, O2, S, PO4, N2 |
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Symbols: ******
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Carbon CO2 Calcium CA+ Nitrogen N2 Magnesium MG2 Oxygen O2 Zinc ZN Hydrogen H2 Iron FE Methane CH4 Ammonia NH3 Phosphorous PO4 Sulfur S Potassium K+ Sodium NA+ |
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Growth Factors: Essential Organic Nutrients
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* Organic compounds that cannot be synthesized by an organism because they lack the genetic and metabolic mechanisms to synthesize them. * Growth factors must be provided as nutrient - Essential: amino acids, vitamins. |
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Nutritional Types: * Main determinants of nutritional types are: - heterotroph & autotroph
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Energy Source: - Chemotroph - gain energy from chemical compounds (can be either autotroph or heterotroph) - Phototroph - gain energy through photosynthesis (can be either autotroph or heterotroph) |
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Sources of Essential Nutrients: Chemotrophs: energy from chemical compounds. |
- Carbon sources: - Heterotroph - must obtain carbon in an organic form made by other living organisms such as proteins, carbohydrates, lipids, and nucleic acids - Autotroph - an organism that uses CO2, an inorganic gas as its carbon source. *Not nutritionally dependent on other living things. |
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Manobolic Classification: All organisms
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Energy source: -Phototrophs (energy from sunlight) -Chemotrophs (energy from chemical compounds) you. Carbon source: - Autotroph (carbon from CO2) - Heterotroph (carbon from organic compounds)
Phototrophs: Autotrophs: Cyanobacteria, vascular plants. Heterotrophs: Heliobacteria, Most green non-sulfur bacteria.
Chemotrophs: Autotrophs: Sulfur-oxidizing bacteria, hydrogen bacteria. Heterotrouphs: Most bacteria, All non-phototrophic eukaryotes-(you) |
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Autotrophs and their energy sources: * Photoautotrophs- energy from sunlight |
- oxygenic photosynthesis - Anoxygenic photosynthesis. |
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Chemoautotrophs (lithoautotrophs)
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- Survive totally on inorganic substances. - Methanogens, a kind of chemoatotroph, produce methane gas under a anaerobic conditions (without air). *mineral and gases. |
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Heterotrophs and Their Energy Sources: -Majority are chemoheterotrophs |
* Two categories: (aerobic respiration) - Saprobes: free-living microorganism that feed on organic detritus from dead organism. *recycle, critical in recycling in this world. - Parasites: derive nutrients from host. * Pathogens, * Some are obligate parasites * one way street. |
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If an organism is degrading large organic molecules to get both carbon and energy, it would be best described as a |
Chemoheterotroph
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Transport |
Movement of chemical across the cell membrane. |
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Passive Transport
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Does not require energy; substances exist in gradient and move form areas of higher concentration toward areas of lower concentration. - Diffusion - Osmosis - diffusion of water - semipermeable membrane, concentration gradient. - Facilitated diffusion - requires a carrier. **Cell Membrane (phospholipids, proteins and sterols*** |
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Active Transport
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requires energy and carrier proteins; gradient independent. - Active transport - Group translocation - transported molecule chemically altered. - Bulk transport- endocytosis, exocytosis, pinocytosis. *** requires energy *** |
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Isotonic Solution- Water concentration is equal inside and outside the cell, rates of equal diffusion on both sides. Hypotonic Solution: Net diffusion of water is into the cell; this swells the protoplast and pushes it tightly against the wall. Wall usually prevents cell from bursting. Hypertonic Solution: Water diffuses out of the cell and shrinks the cell membrane away from the cell wall; process is know as Plasmolysis . ie* (too much fertilizer) |
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Facilitated Diffusion (Passive Transport)
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Still going with a gradient like diffusion- just to big to go through, and pairs up with a carrier molecule- latches and takes it through or can without a carrier molecule.
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Carrier Mediated Active Transport
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Membrane-bound transporter proteins (permeases) interact with nearby solute binding proteins that carry essential solutes (sodium, iron, sugars) Once binding protein attaches to a specific stie, an ATP is activated and generates energy to pump the solute into the cell's interior through a special channel in the permease. *NA & K+ |
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If a cell is in a concentrated glucose solution and the glucose is moving into the cell through a carrier protein, this would be an example of
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Active Transport *Moving against the gradient. |
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Environmental Factors that Influence Microbes
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* Niche: totality of adaptations organisms make to their habitat. * Environmental factors affect the function of metabolic enzymes - Factors include: * Temperature * Oxygen requirements * pH * Osmotic pressure * Barometric pressure ***Some require temp, O2 and some don't** |
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3 Cardinal Temperatures |
- Minimum temperature - lowest temperature that permits a microbe's growth and metabolism. - Maximum Temperature - highest temperature that permits a microbe's growth and metabolism. - Optimum temperature - promotes the fastest rate of growth and metabolism. |
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* 3 Temperature Adaptation Groups 1) Psychrophiles |
Optimum temperature below 15 C; capable of growth at 0 C. |
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2) Mysophilies
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Optimum temperature 20C-40C; most human pathogens. |
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3) Thermophiles
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Optimum temperature greater than 45C |
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Gas Requirements****Know!
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Oxygen: *As oxygen is utilized it is transformed into several toxic products. - singlet oxygen (O2), superoxide ion (O2-), peroxide (H2O2), and hydroxyl radicals (OH-) * Most cells have developed enzymes that neutralize these chemical: - Superoxide dismutes, catalase. *** If a microbe is not capable of dealing with toxic oxygen, it if forced to live in oxygen free habitats.
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**Categories of Oxygen Requirements: Know!
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* Aerobic- utilizes oxygen and can detoxify it. * Obligate aerobic - cannot grow without oxygen * Facultative anaerobe - utilizes oxygen but can also grow in its absence. * Microaerophilic - requires only a small amount of oxygen * Anaerobe - does not utilize oxygen * Obligate anaerobe - lacks the enzymes to detoxify oxygen so it cannot survive in an oxygen environment. * Aerotolerant anaerobes - do not utilize oxygen but can survive and grow in its presence |
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**Culturing by Oxygen Requirement
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Two different ways of culturing anaerobes: - Use of a medium such as Thioglucollate broth (reducing agent) - note tube #4 and use of anaerobic environmental chambers. * removes O2 from it. |
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Carbon Dioxide Requirement: All microbes require some carbon dioxide in their metabolism. * Capnophile: |
grows best at higher CO2 tensions than normally present in the atmosphere. *Loves CO2! |
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Effects of pH! Know! **** - Majority of microorganisms grow at a pH between 6 and 8 (neutrophils)- strong bases and/ or acids tend to decrease effectiveness or inactivate enzymes and other proteins. |
Acidophiles - grow at extreme acid pH. * many molds/yeasts, acidic pools, coal piles. and some bacteria. Alkalinophils - grow at extreme alkaline pH. * Hot pools and soils with high levels of basic mineral. Bacteria that decompose urine increases alkaline conditions. * (both acidophiles and alkalinophiles have developed enzymes and other proteins that are resistant to damage by strong acids and bases) |
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Osmotic Pressure * Most microbes exist under hypotonic or isotonic conditions. |
Halophiles - require a high concentration of salt. High salt! Osmotolerant - do not require high concentration of solute but can tolerate it when it occurs. Tolerates salt! * These organisms have developed modifications in their cell walls and to some extent membranes, to allow them to survive. |
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The environmental Factors:
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Bariophiles - can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure. * For example: deep sea prokaryotes and eukaryotes such as Forminifera sp |
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Chlamydomonas nivlalis grows in Alaska glaciers and its photosynthetic pigments give the snow a red crust. This organism would best be describes as a????? |
Psychrophile.
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Ecological Association Among Microorganisms: Microbial Associations Symbiotic - |
- Organisms live in close nutritional relationships, required by one or both members * Mutualism - Obligatory, dependent, both members benefit. * Commensalism - The commercial benefits; other member not harmed. * Parasitism - Parasite is dependent and benefits; host harmed. |
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Microbial Associations: Nonsymbiotic
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- Organisms are free-living relationship not required for survival. * Synergism - members cooperate and share nutrients. * Antagonism - Some members are inhibited or destroyed by others. |
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Interrelationships between Microbes and Humans
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flora. * Commensal, parasitic, and syngergistic relationship. * Where? Penis-urethra. Example: how to get a clean urine sample. clean penis, urinate some, everyone has flora. |
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Microbial Biofilms |
* result when organisms attach to a substrate by some form of extracellular matrix that binds them together in complex organized layers. * Dominates the structure of most natural environments on earth. |
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*The study of Microbial Growth* |
Growth occurs at two levels: growth at a cellular level with increase in size, and increase in population. * Division of bacterial cells occurs mainly through Binary Fission (transverse)****(know) - Parent cell enlarges, duplicates its chromosome, and forms a central transverse septum dividing the cell into two daughter cells. |
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**Binary Fission-Prokaryotes**
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What cannot be seen is the synthesis and activity gearing up for cell division. 2) Chromosome replication and cell enlargement: The parent cell duplicates the chromosomes and synthesizes new structures that enlarge the cell in preparation for the daughter cells. 3) Chromosomes division and Septation: the chromosomes affix to the cytoskeleton and are separated into the forming cells. The cell lays down a septum that begins to wall off the new cells. Other components (ribosomes) are equally distributed to the developing cells. 4) Completion of cell compartments: the septum is synthesized completely through the center, and the cell membrane patches itself so that there are two separate cell chambers. 5) End of cell division cycle: daughter cells are now independent units. Some species will separate completely as shown here, while others will remain attached, forming chains or pairs, for example. |
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**Rate of Population Growth**
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* Each new fission cycle increases the population by a factor of 2 - exponential growth. * Generation times vary from minutes to day. |
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**The population Growth Curve:** |
- Stages in the normal growth curve: 1) Lag phase - "flat" period of adjustment, enlargement; little growth> |
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The Population Growth Curve:
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1) Lag phase 2) Exponential growth phase 3) Stationary phase - rate of cell growth equals rate of cell death caused by depleted nutrients and O2, excretion of organic acids and pollutants. 4) Death phase - as limiting factors intensify, cells die exponentially. |
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Methods of Analyzing Population Growth:
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* Degree of cloudiness, turbidity, reflects the relative population size. ****way of measuring cloudiness. |