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64 Cards in this Set
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Nutrition |
chemical substances (nutrients) obtained from environment & used in cellular activities. |
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Nitrogen sources: |
Makes up proteins, DNA, RNA, ATP. (These are the primary sources of N for heterotrophs) |
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Adaptation: |
Microbes survive in their habitats through gradual adjustment of anatomy & physiology. |
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Nutrition: |
Is the process which chemical nutrients are acquired through the environment & used in cellular activities (Metabolism & growth) |
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Essential Nutrients |
Any element or molecule that must be provided to an organism. Have to be obtained from the environment |
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2 categories of essential nutrients: |
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Macronutrients |
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Micronutrients |
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Examples of micronutrients: |
manganese, zinc, & nickle |
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Organic Nutrients |
molecules that contain basic framework of Carbon & Hydrogen & usually products of living things.
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Natural Organic Molecules |
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Inorganic Nutrients |
atom or molecule that contains a combination of atoms other than carbon and hydrogen. |
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How do photosynthetic bacteria obtain their nutrients? |
inorganic form from the environment. Others require combo of organic & inorganic. |
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Heterotroph |
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Autotroph |
organism uses inorganic CO2 as its Carbon source.
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Growth Factors |
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phototrophs or chemotrophs |
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Carbon |
CO2 is produced by respiration & used in photosynthesis. (p. 189) |
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Examples of inorganic nutrients: |
Metals and their salts (magnesium sulfate, ferric nitrate, sodium phosphate), gases (oxygen, carbon dioxide) and water |
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Chemical Analysis of microbial cytoplasm |
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Carbon sources of essential nutrients: |
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Autotroph |
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Heterotroph |
must obtain carbon in an organic form made by other living organisms |
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Growth Factors - Essential Organic Nutrients: |
Organic compounds that cannot be synthesized by an organism because they lack the genetic and metabolic mechanisms to synthesize them |
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Phototrophs: |
gain energy through photosynthesis |
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Chemotroph |
gain energy from chemical compounds |
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Passive Transport |
does not require energy; substances exist in a gradient and move from areas of higher concentration toward areas of lower concentration |
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Diffusion |
movement of molecules down a concentration gradient |
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Osmosis |
diffusion of water through a selectively permeable membrane |
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Facilitated Diffusion |
requires a carrier protein to assist in transport across the membrane |
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Active Transport |
insures nutrients in low supply are transported into the cell – Uses membrane proteins and pumps – carrier-mediated – Requires ATP |
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Bulk Transport |
• endocytosis – liquids/solids engulfed into vessicle – phagocytosis – large solids, whole cells – Pinocytosis - liquids |
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Niche |
all adaptations organisms make to their habitat |
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• Environmental factors affect the function of metabolic enzymes • Factors include: |
– Temperature – Oxygen requirements – pH – Osmotic pressure – Barometric pressure |
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3 Cardinal Temperatures: |
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Minimum Temperature |
lowest temperature that permits a microbe’s growth and metabolism |
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Maximum Temperature |
highest temperature that permits a microbe’s growth and metabolism |
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Optimum Temperature |
promotes the fastest rate of growth & metabolism – S. aureus: 6-46°C |
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Temperature Adaptation Groups |
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Psychrophiles |
- optimum temperature below 15C (60F) - capable of growth at 0C |
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Mesophiles |
- optimum temperature 20-40C (68-104F) - most human pathogens |
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Thermophiles |
- optimum temperature greater than 45C (113F) |
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Gas Requirements |
Oxygen: • As oxygen is used, it is transformed into toxic products: – Singlet oxygen (1O2), superoxide ion (O2 -), peroxide (H2O2), and hydroxyl radicals (OH-) • Most cells have developed enzymes that neutralize these chemicals: – Superoxide dismutase, catalase • If a microbe is not capable of dealing with toxic oxygen, it is forced to live in oxygen free habitats |
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Aerobe: |
utilizes oxygen and can detoxify it – Obligate aerobe – cannot grow without oxygen – Facultative anaerobe – utilizes oxygen but can also grow in its absence (through fermentation) |
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Microaerophilic |
requires only a small amount of oxygen |
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Anaerobe |
Does not utilize oxygen |
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Oligate anaerobe |
lacks the enzymes to detoxify oxygen so cannot survive in an oxygen environment • large intestine anaerobic, gas gangrene and tetanus are anaerobic bacilli |
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Rate of population growth: Nf :Ni |
Every hour it doubles 3x |
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Aerotolerant anaerobes |
do not utilize oxygen but can survive and grow in its presence |
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Capnophile |
grows best at higher CO2 tensions than normally present in the atmosphere |
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Effects of pH |
• Majority of microorganisms grow at a pH between 6 and 8 • Obligate acidophiles – grow at extreme acid pH • Alkalinophiles – grow at extreme alkaline pH |
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Osmotic Pressure |
Most microbes exist under hypotonic or isotonic conditions |
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Halophiles |
require a high concentration of salt |
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Osmotolerant |
do not require high concentration of solute but can tolerate it when it occurs – Staphylococcus aureus – Common spoilage bacteria/fungi can thrive in high sugar/salt containing foods |
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Barophiles |
can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure |
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Symbiotic |
two organisms live together in a close partnership |
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Mutualism |
obligatory, dependent; both members benefit |
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Commensalism |
commensal member benefits, other member neither harmed nor benefited |
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Parasitism |
parasite is dependent and benefits; host is harmed |
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Non-symbiotic |
organisms are free-living; relationships not required for survival |
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Synergism |
members cooperate to produce a result that none of them could do alone • Microbes involved in soil nutrient cycling |
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Antagonism |
actions of one organism affect the success or survival of others in the same community (competition) |
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Antibiosis |
production of inhibitory substances, such as antibiotics |
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Biofilms |
result when organisms attach to a substrate by some form of extracellular matrix that binds them together in complex organized layers |