Term
| What are 2 types of cell division that can occur in bacteria? |
|
Definition
|
|
Term
|
Definition
| the increase in the number of microbial cells occurring from cell division |
|
|
Term
| What are the 4 phases of the standard bacterial growth curve? |
|
Definition
1) lag phase
2) log phase
3) stationary phase
4) death or decline phase |
|
|
Term
|
Definition
| first of 4 major phases of bacterial growth curve, organisms grow in size but not in number |
|
|
Term
|
Definition
| second of 4 major phases of bacterial growth curve, cells divide at exponential or logarithmic rate |
|
|
Term
|
Definition
| third of 4 major phases of bacterial growth curve in which new cells are produced at the same rate that old cells die, leaving the number of live cells constant |
|
|
Term
|
Definition
| fourth of the 4 major phases of bacterial growth curve in which cells lose their ability to divide and thus die |
|
|
Term
|
Definition
| time required for a population of organisms to double in number |
|
|
Term
|
Definition
| hypothetical pattern of growth during the log phase in which all the cells in a culture divide at the same time |
|
|
Term
|
Definition
| natural pattern of growth during the log phase in which every cell in a culture divides at some point during the generation time, but not simultaneously |
|
|
Term
|
Definition
| device for maintaining the logarithmic growth of a culture by the continuous addition of fresh medium |
|
|
Term
|
Definition
| group of descendants from the original cell |
|
|
Term
|
Definition
| method of measurement in which successive 1:10 dilutions are made from the original sample to give a countable number of organisms |
|
|
Term
|
Definition
| plate containing separate colonies and used to prepare a pure culture |
|
|
Term
|
Definition
| method used to prepare pure cultures using serial dilutions, each of which is mixed with melted agar and poured into a sterile Petri plate |
|
|
Term
|
Definition
| technique used to prepare pure cultures by placing a diluted sample of cells on the surface of an agar plate and then spreading the sample evenly over the surface |
|
|
Term
|
Definition
| (colony forming unit) live bacterial cells which can give rise to a colony |
|
|
Term
|
Definition
| number of colonies on an agar plate small enough so that one can clearly distinguish and count them (30-300) |
|
|
Term
|
Definition
method of measuring bacterial growth by counting cells in a known volume of medium that fills a specially calibrated counting chamber on a microscopic slide
-multiply # of colonies (CFUs) by dilution factor
Ex. 30 x 100 = 3.0 x 10^3 CFU/mL |
|
|
Term
| What are some disadvantages of a direct microscopic count? |
|
Definition
| cannot distinguish between dead and live cells, only accurate if large # of bacteria is present |
|
|
Term
| most probably number method |
|
Definition
| statistical method of measuring bacterial growth, used when samples contain too few organisms to give reliable measure by the plate count method |
|
|
Term
|
Definition
| method of estimating size of bacterial populations in which a known volume of air or water is drawn through a filter with pores too small to allow passage of bacteria |
|
|
Term
|
Definition
cloudy appearance in a culture tube indicating the presence of organisms, can be measured with a spectrophometer
-useful because it doesn't disturb culture, but cannot tell between live and dead cells |
|
|
Term
|
Definition
| instrument used to measure the turbidity of a culture, indicating the amount of organisms present |
|
|
Term
|
Definition
| acid-loving organism that grows best in an environment with pH of 4.0-5.4, although some can grow in pH as low as 0.1 |
|
|
Term
|
Definition
| organism that grows best at pH of 5.4 to 8.5 |
|
|
Term
|
Definition
| a base loving organism that grows best in an environment with pH of 7.0-11.5 |
|
|
Term
|
Definition
| cold loving organism that grows best at temps of 15-20 C |
|
|
Term
|
Definition
| organisms that grow best at temps between 25-40 C, includes most bacteria |
|
|
Term
|
Definition
| heat loving bacteria that grow best at 50-60 C |
|
|
Term
|
Definition
| organism that can grow only at temperatures above 37 C |
|
|
Term
|
Definition
| organism that cannot grow at temperatures above 20 C |
|
|
Term
|
Definition
| bacterium that must have free oxygen to grow |
|
|
Term
|
Definition
| bacterium that is killed by free oxygen |
|
|
Term
|
Definition
bacterium that carries on aerobic metabolism when oxygen is present but shifts to anaerobic
metabolism when oxygen is absent
Ex. E. coli & Staphylococcus |
|
|
Term
|
Definition
| organism that grows best at temperatures below 20 C but can also grow at temps above 20C |
|
|
Term
|
Definition
| organism that can grow both above and below 37 C |
|
|
Term
|
Definition
| organisms that grow best in the presence of a small amount of free oxygen |
|
|
Term
|
Definition
| carbon-dioxide loving organisms that thrive under conditions of low oxygen and high carbon dioxide concentrations |
|
|
Term
|
Definition
organisms that survive in the presence of oxygen but do not use it in their metabolism
Ex. Lactobacillus |
|
|
Term
| Which organisms, in terms of oxygen requirements, have the most complex enzyme systems? |
|
Definition
| facultative anaerobes bc they have one set for using oxygen and one set for not |
|
|
Term
|
Definition
| highly reactive form of oxygen that kills obligate anaerobes |
|
|
Term
|
Definition
| enzyme that converts superoxide to molecular oxygen and hydrogen peroxide |
|
|
Term
|
Definition
| enzyme that converts hydrogen peroxide to water and molecular oxygen |
|
|
Term
|
Definition
| pressure exerted by standing water |
|
|
Term
|
Definition
| bacteria that must live at high pressures to survive, membranes and enzymes require pressure to function properly and stay in proper 3D shape |
|
|
Term
|
Definition
| shrinking of a cell with separation of the cell membrane from the cell wall, resulting from loss of water in a hypertonic solution |
|
|
Term
|
Definition
| salt loving organisms that require moderate to large amounts of salt, typically found in the ocean |
|
|
Term
|
Definition
| microorganisms with special nutritional needs that can be difficult to meet in the lab |
|
|
Term
|
Definition
| number of nutrients an organism must obtain to grow |
|
|
Term
|
Definition
| extracellular, periplasmic, and cytoplasmic |
|
|
Term
| In what type of bacteria are extracellular enzymes usually found? |
|
Definition
| gram positive, act in medium around bacteria |
|
|
Term
| In what type of bacteria are periplasmic enzymes usually found? |
|
Definition
| gram negative bacteria, act in periplasmic space |
|
|
Term
|
Definition
|
|
Term
| How are bacterial endospores different from fungal spores? |
|
Definition
in bacteria, a single spore forms inside bacterial cell, typically during stationary phase
-means of protection rather than reproduction
Fungal spores are formed in great numbers and as a way of reproduction |
|
|
Term
|
Definition
| living part of the endospore, made of cellular RNA and cytoplasmic proteins around the DNA |
|
|
Term
|
Definition
| a component of the core which contributes to an endospore's heat resistance |
|
|
Term
|
Definition
| a cell membrane without a cell wall that grows around the core of an endospore |
|
|
Term
|
Definition
| laminated layer of a spore that surrounds the endospore septum and is created by peptidoglycan secreted from the endospore septum, protects core from changes in osmotic pressure |
|
|
Term
|
Definition
| keratin-like protein material laid down around the cortex by the mother cell |
|
|
Term
|
Definition
lipid-protein membrane formed outside the coat of a spore by the mother cell
-function is unknown |
|
|
Term
|
Definition
| when a spore returns to its vegetative state |
|
|
Term
| What are the 3 stages of germination? |
|
Definition
| activation, germination proper, outgrowth |
|
|
Term
|
Definition
| traumatic agent damages spore coat (low pH or heat) |
|
|
Term
|
Definition
| water and germination agent (such as amino acid or inorganic ions) penetrate damaged coat |
|
|
Term
|
Definition
cells returns to its vegetative state in a medium with adequate nutrients
-proteins, RNA, and DNA are synthesized |
|
|
Term
|
Definition
| spherical, thick-walled cell that resembles an endospore, formed by certain bacteria |
|
|
Term
|
Definition
| small, asexual, arial spore organized into chains in some bacteria and fungi |
|
|
Term
|
Definition
| culture that contains only a single species of an organism |
|
|
Term
|
Definition
| bacteria are lightly spread over surface of agar plates, resulting in isolated colonies |
|
|
Term
|
Definition
| medium prepared in lab from materials of precise or reasonable well-defined composition |
|
|
Term
|
Definition
| a synthetic medium which contains known specific kinds and amounts of chemicals |
|
|
Term
|
Definition
| a synthetic medium that contains reasonably familiar materials but varies slightly in chemical composition from batch to batch |
|
|
Term
|
Definition
encourages growth of some but suppresses growth of others
Ex. SPS agar (allows growth of C. botulinum but inhibits other Clostridum species) |
|
|
Term
|
Definition
has constituent that causes an observable change (color or pH) when biochemical reaction occurs
allows different types of colonies to be distinguished
Ex. SPS agar |
|
|
Term
|
Definition
contains special nutrients that allow growth of particular organisms that might not otherwise be present in sufficient numbers
does not suppress growth of others |
|
|
Term
| Explain the purpose of the candle in a jar method of growing bacteria. |
|
Definition
| the candle is burned until the flame goes out meaning that there is a small amount of oxygen and large amount of CO2 left and so microaerophiles and anaerobes grow well |
|
|
Term
|
Definition
| a reserve culture used to store an isolated organism in pure condition for use in the lab |
|
|
Term
|
Definition
| set of procedures used to minimize chances that cultures will be contaminated by organisms from the environment |
|
|
Term
|
Definition
| cultures in which organisms are maintained in a dormant state |
|
|
Term
|
Definition
| a type of preserved culture that maintains the organisms w/characteristics as originally defined |
|
|
