Chapter 5 – Microbiology Questions And Answers – Flashcards
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| Asexual Reproduction |
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| Process to maintain genetic constancy while increasing cell numbers |
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| Binary Fission |
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| A mechanism Majority of bacteria reproduce. Is much simpler than the mechanism of cell division seen in eucaryotic cells. |
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| Generation Time |
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| Time it takes for a population of bacteria to double in number. |
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| Short Generation Time |
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| 20-60 minutes under optimum conditions |
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| Long Generation Time |
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| Most common pathogens in the body time is closer to 5-10 hours. |
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| Tetrad |
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| Complete separation of cells during Binary fission doesnt occur, occurs in 2 planes, and creates a center square with four cocci, one located at each conner |
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| Sarcinae |
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| Complete separation of cells during Binary fission doesn't occur, occurs in 3 planes, and creates a center square with 8 with one coccus at each corner. |
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| Lag Phase |
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| Transfer of bacteria from one medium to another. Bacteria is becoming accustomed to new environment. |
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| Log Phase |
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| Binary Fission Occurs. Bacteria growth in numbers, not in size. Generation time is included at this time. Continues culture can also be conducted to keep bacteria growing. Exponential growth can be 20 minutes to 20 hours. Symptoms can occur. |
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| Stationary Phase |
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| Cell Reproduction is balance by cell death. Nutrients become scarce. Toxins (Waste) build up creating Unfavorable conditions. |
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| Decline Phase (Death Phase) |
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| No growth. Older bacteria will die first followed by new cells. may form, begin sporulation process. Nutrients are limited. |
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| Endospores |
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| highly resistant structures coming from sporulation |
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| Sporulation |
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| A process that a mother cell will wrap around new cell and new cell will become spore. |
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| Media |
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| Microbiological medium used for culturing bacteria, molds, and other microorganisms. 1)Liquid 2) Solid 3) Semisolid |
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| Liquid Media |
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| Tryptose Broth |
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| Solid Media |
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| Tryptose Agar |
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| Semisolid Media |
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| SS Media for Selmonela |
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| Factors affecting bacterial growth |
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| 1)pH 2)temperature 3)Oxygen Concentration 4)Osmotic Conditions |
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| Optimum pH |
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| pH at which an organism grows best |
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| Acidophiles |
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| Organisms whose Optimum pH is relatively to highly acidic. Acid-tolerant |
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| Neutrophiles |
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| Organisms whose Optimum pH range is about pH7, plus or minus approx. 1.5pH units. |
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| Alkaphiles |
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| Organisms whose optimum pH is relatively too highly basic |
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| Psychrophile |
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| Cold adapted organisms. Grow at or below 20 degrees |
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| Mesophile |
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| Organisms growth temp. is between 20°c-40°c |
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| Thermoduric |
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| Can be exposed to a brief amount of heat. |
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| Thermophiles |
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| High temp. adapted organisms. Multiply best at temps. around 60c but still multiply from 40°c to 70°c |
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| Obligate Aerobes |
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| Need Oxygen to gas as a final electron acceptor to make cellular energy. |
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| Obligate Anaerobe |
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| Few Fungal and Protozoal species. No Oxygen will be killed or inhibited if Oxygen is present. |
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| Microaerophiles |
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| Survive in environments where the concentration of oxygen is relatively low |
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| Psychrotrophs / Psychrotolerant |
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| Cold loving. Have a higher optimal growth temp. as well as a higher minimal and maximal growth temperature. |
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| Anaerobes |
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| Microbes that do not or cannot use oxygen |
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| Aerotolerant |
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| Insensitive to oxygen |
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| Hyperthermophiles |
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| Grow optimally at temp. that exceed 80°c |
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| Asexual Cycle |
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| DNA of the vegetative cell replicates and the cell elongates. Binary Fission |
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| Sporulation Cycle |
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| Nutrient conditions become limiting, becoming spores |
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| Bacterial Growth Curve |
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| Illustrates the events occurring over time |
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| Dipicolinic Acid |
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| Organic substance that helps stabilize the proteins and DNA, after cell is/spore is engulfed by the mother cell. |
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| Facultative Microbes |
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| Microbes can grow in either the presence or reduced concentration of oxygen. |
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| Thioglycollate Broth |
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| A way to test an organisms oxygen sensitivity. Binds free oxygen so that only fresh oxygen entering the top of the tube would be available. |
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| Capnophilic Bacteria |
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| Require an atmosphere low in oxygen but rich in carbon dioxide |
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| Barophiles |
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| survive at high atmospheric pressure |
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| Nonhalophiles |
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| Cells Unable to grow in the presence of salt |
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| Halophile |
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| Cells Require salt to survive |
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| Halotolerant |
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| Cells grow best with out salt, but can tolerate low concentrations of salt |
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| Extreme Halophiles |
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| Cells tolerate salt concentration of 15 to 30% |
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| Agar |
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| Polysaccharide derived from red algae. Contains no essential nutrients. Remains solid under 36?C |
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| Complex Medium |
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| Chemmicaly undefined medium contains nutrients in which the exact componnent or their quantity is not completely known medium |
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| Synthetic Medium |
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| Precise chemical composition and amount of all components are known. Used to find organisms growth requirements. |
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| Differential Medium |
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| Contains specific chemicals to indicate which species possess and which lack a particular biochemical process |
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| Enriched Medium |
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| contains special nutrients for organisms containing complex nutritional requirments |
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| VBNC (Viable but not-culturable) |
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| Impossible to estimate accurately microbial diversity in an environment based solely on culturability |
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| Biofilm |
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| Mixed microorganisms with other species, in a so-called mixed culture |
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| Pure culture |
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| A population consisting of only one species |
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| Pour plate method |
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| Sterile dish. Molten Agar medium added Agar hardened cells divide to form discrete colonies throughout agar. |
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| Streak Plate Method |
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| Nutrient Agar plate. Add bacteria with Loop |
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| Turbibity |
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| Cloudiness |
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| Colony-forming units (CFUs) |
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| Expressed as a number in a Standard plate count |
