question

Psychrophiles

answer

Cold loving microbes

question

Mesophiles

answer

Moderate temperature loving microbes. Most common type of microbe which have an optimum growth of 25-40 degrees Celsius

question

Thermophiles

answer

Heat loving microbes who can not grow in temperatures below 45 degrees celsius.

question

Minimum growth temperature

answer

Is the lowest temperature at which the species will grow

question

Optimum growth temperature

answer

Is the temperature at which the species grows best.

question

Maximum growth temperature

answer

Is the highest temperature at which growth is possible.

question

Pscyhrotroph

answer

An organism that is capable of growth between about 0 degrees Celsius to 30 degrees celsius.

question

Hyperthermophiles or extreme thermophiles

answer

Microbes who are members of the Archaea that have a optimum growth temperature of 80 degrees Celsius or higher

question

Acidophiles

answer

Bacteria that are remarkably tolerant of acidity.

question

Plasmolysis

answer

Shrinkage of the cell’s cytoplasm.

question

Extreme halophiles

answer

Organisms who have adapted so well to high salt concentrations that they actually require them for growth.

question

Facultative Halophiles

answer

Organisms that do not require high salt concentration but are able to grow at salt concentrations up to 2%, a concentration that inhibits the growth of many other organisms. A few of this species can tolerate even 15% salt.

question

Trace Elements

answer

Microbes that require very small amounts of other mineral elements, such as iron, copper, molybdenum, and zinc. Most are essential for the functions of certain enzymes usually as cofactors.

question

Obligate aerobes

answer

Organisms that require oxygen to live.

question

Facultative Anaerobes

answer

Aerobic bacteria that have developed and retained the ability to continue growing in the absence of oxygen. These organisms can use oxygen when it is present but are able to continue growth by using fermentation or anaerobic respiration when oxygen is not available.

question

Obligate anaerobes

answer

Are bacteria that are unable to use molecular oxygen for energy-yielding reactions.

question

Singlet Oxygen

answer

Is normal molecular oxygen that has been boosted into a higher-energy state and is extremely reactive.

question

Superoxide radicals or Superoxide anions

answer

Are formed in small amounts during the normal respiration of organisms that use oxygen as a final electron acceptor forming water.

question

Superoxide dismutase (SOD)

answer

An enzyme that destroys superoxide.

question

Peroxide anion

answer

An oxygen anion consisting of two atoms of oxygen.

question

Catalase

answer

An enzyme that breaks down hydrogen peroxide.

question

Peroxidase

answer

An enzyme that destroys hydrogen peroxide.

question

Ozone (o3)

answer

O3

question

Hydroxyl radical

answer

Is another intermediate form of oxygen and probably the most reactive. It is formed in the cellular cytoplasm by ionizing radiation.

question

Aerotolerant anaerobes

answer

Organisms that does not use molecular oxygen but is not affected by its presence.

question

Microaerophile

answer

An organism that grows best in an environment with less molecular oxygen than is normally found in air.

question

Organic Growth Factors

answer

Essential organic compounds an organism is unable to synthesize. They must be directly obtained from the environment. Example: Vitamins, amino acids, purines, and pyrimidines.

question

Biofilms

answer

A microbial community that usually forms as a slimy layer on a surface.

question

Culture medium

answer

Ia nutrient material prepared for the growth of microorganisms in a laboratory.

question

Inoculum

answer

Microbes that are introduced into a culture medium to initiate growth.

question

Culture

answer

The microbes that grow and multiply in or on a culture medium.

question

Sterile

answer

It must initially contain no living microorganisms.

question

Agar

answer

Has long been used as a thickener in foods such as jellies and ice cream. A complex polysaccharide derived from a marine alga.

question

Chemically Defined medium

answer

Is one whose exact chemical composition is known.

question

Fastidious

answer

Organisms that require growth factors

question

Complex media

answer

Media that is made up of nutrients including extracts from yeasts, meat, or plants, or digest of proteins from these and other sources.

question

Nutrient Broth

answer

A complex medium in liquid form.

question

Nutrient Agar

answer

When agar is added to a complex medium in liquid form.

question

Reducing media

answer

A culture medium containing ingredients that will remove dissolving oxygen from the medium to allow the growth of anaerobes.

question

Canophiles

answer

Microbes that grow better at high co2 concentrations

question

Selective Media

answer

Designed to suppress the growth of unwanted bacteria and encourage the growth of the desired microbes.

question

Differential Media

answer

Make it easier to distinguish colonies of the desired organism from other colonies growing on the same plate.

question

Streptococcus pyogenes

answer

The bacterium that causes strep throat, showing a clear ring around their colonies where they have lysed the surrounding blood cells.

question

Enrichment Culture

answer

A culture medium used for preliminary isolation that favors the growth of a particular microorganism.

question

Colony

answer

A group of microorganisms that theoretically arises from a single spore or vegetative cell attach to on another in clumps or chains. They have distinctive appearance that distinguishes one microbe from another.

question

Streak Plate Method

answer

The isolation method most commonly used to get pure cultures. A sterile inoculating loop is dipped into a mixed culture that contains more than one type of microbe and is streaked in a pattern over the surface of the nutrient medium.

question

Deep-freezing

answer

Is the process in which a pure culture of microbes is placed in a suspending liquid and quick-frozen at temperatures ranging from -50 degrees celsius to -95 degrees celsius. The culture can usually be thawed even several years later.

question

Lyophilization (Freeze-Drying)

answer

A suspension of microbes is quickly frozen at temperatures ranging from -54 degrees celsius to -72 degrees Celsius and the water is removed by a high vacuum. While under vacuum, the container is sealed by melting the glass with a high-temperature torch. The remaining powder-like residue that contains the surviving microbes can be stored for years. These organisms can be revived at any time by hydration with a suitable liquid nutrient medium.

question

Binary Fission

answer

Prokaryotic cell reproduction by division into two daughter cells.

question

Budding

answer

Bacterial species reproduce by forming small initial outgrowth that enlarges until its size approaches that of the parent cell and then it separate.

question

Generation Time

answer

The time required for a cell to divide. This time period varies considerably among organisms and with environmental conditions such as temperature.

question

Bacterial Growth Curve

answer

A graph indicating the growth of a bacterial population over time.

question

Lag Phase

answer

The time interval in a bacterial growth curve during which there is no growth.

question

Log Phase
or
Exponential Growth Phase

answer

The cells begin to divide and enter a period of growth, or logarithmic increase. Is also the time when cells are most active metabolically and is preferred for industrial purposes where a product needs to be produced efficiently.

question

Stationary Phase

answer

The period in a bacterial growth curve when the number of cells dividing equals the number dying.

question

Death Phase or Logarithmic Decline Phase

answer

When the number of deaths eventually exceeds the number of new cells formed and population enters death. The phase continues until the population is diminished to a tiny fraction of the number of cells in the previous phase or until the population dies out entirely.

question

Plate Count

answer

A method of measuring bacterial populations and measures the number of viable cells however may take up to 24 hours. Assumes that each bacterium grows and divides to produce a single colony.

question

Serial Dilution

answer

The process of diluting a sample several times.

question

Pour Plate Method

answer

A method of inoculating a solid nutrient medium by mixing bacteria in the melted medium and pouring the medium into a Petri Dish to solidify.

question

Spread Plate Method

answer

A plate count method in which inoculum is spread over the surface of a solid culture medium.

question

Filtration

answer

The passage of a liquid of gas through a screen like material. Filter removes bacteria.

question

Most Probable Number Method (MPN)

answer

A statistical determination of the number of coliforms per 100 ml of water or 100 grams of food.

question

Direct Microscopic Count

answer

Enumeration of cells by observation through a microscope.

question

Turbidity

answer

Is a practical way of monitoring bacterial growth.

question

Spectrophotometer

answer

Is an instrument used to measure turbidity. A beam of light is transmitted through a bacterial suspension to a light sensitive detector. As bacteria numbers increase the amount of light will decrease.

question

Optical Density OD

answer

Is the change of light as a logarithmic expression which is calculated as Abs=2-log of transmittance %. The absorbance is used to plot bacterial growth.

question

Metabolic Activity

answer

Method assumes that the amount of a certain metabolic product such as carbon dioxide is in direct proportion to the number of bacteria present.

question

Dry Weight

answer

The fungus is removed from the growth medium, filtered to remove extraneous material and dried in a desiccator.

Microbiology-Chapter Six Terms – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards