MicroBio - Chapter 6 Study Questions

Vocabulary flashcards based on lecture notes about microbial nutrition and growth.

Essential Nutrient

A nutrient that must be provided to an organism.

Bacterial cells are enumerated as "colony-forming units" because Blank______.

chains or clusters of bacterial cells may form a colony

Organisms that prefer pools and soils with pH values in the basic range are called

alkalinophiles

highly reactive, toxic byproducts of oxygen metabolism?

• Hydrogen peroxide (H2O2)

• Superoxide ion (O2-)

• Hydroxyl radical (OH−)

Which is FALSE regarding binary fission?

Like meiosis in eukaryotes, it specifically produces daughter cells with genetic variation.

Growth of a bacterial culture in growth medium in a test tube is defined as a closed culture, meaning that

nutrients are limited and waste products are not removed

A method traditionally used to observe population growth pattern is a ______ ______ count technique, in which the total number of live cells is counted over a given time period.

viable plate

Hydrogen peroxide formed during aerobic respiration is converted to water and oxygen by the enzyme ____

catalase

The viable plate method is based on the principle that each colony represents ______ cell or colony-forming unit from the original sample.

one

The majority of bacteria grow by a process called ___ _____

binary fission

A batch culturing system where nutrients and space are finite and there is no mechanism for the removal of waste products is called a(n)

closed culture

The conversion of a toxic superoxide ion to hydrogen peroxide requires the enzyme ____ ____

superoxide dismutase

organism that is an important human pathogen, and is classified as a facultative halophile?

S. aureus

Macronutrients

Required in large quantities; examples include carbon, hydrogen, oxygen, nitrogen, phosphate, and sulfur.

Micronutrients (Trace elements)

Required in much smaller amounts and are involved in enzyme function and maintenance of protein structure; examples include manganese, zinc, and nickel.

Cardinal Temperatures

The range of temperatures for the growth of a given microbial species.

Minimum Temperature

Lowest temperature that permits a microbe to grow and get nutrients.

Maximum Temperature

Highest temperature at which growth and metabolism can occur.

Optimum Temperature

Temperature between the minimum and maximum that promotes the fastest rate of growth and metabolism.

Psychrophiles

Microbes with an optimum temperature up to 20°C.

Psychrotolerant/psychrotrophs

Microbes with an optimum temperature between 15-30°C.

Mesophiles

Microbes with an optimum temperature between 20-40°C; inhabit animals, plants, soil, and water in temperate, subtropical, and tropical regions.

Thermophiles

Microbes with an optimum temperature greater than 45°C.

Extreme Thermophiles (Hyperthermophiles)

Microbes with an optimum temperature greater than 80°C.

Aerobes

Can use gaseous oxygen in their metabolism and posses the enzymes needed to process toxic oxygen products.

Obligate aerobe

An organism that cannot grow without oxygen.

Microaerophiles

Are harmed by normal atmospheric concentrations of oxygen but require a small amount of it in metabolism

Facultative Anaerobes

Do not require oxygen for metabolism but use it when it is present; can also grow anaerobically.

Anaerobes

Lack the metabolic enzyme systems for using oxygen in respiration; also lack the enzymes for processing toxic oxygen and die in its presence.

Aerotolerant Anaerobes

Do not utilize oxygen but can survive and grow to a limited extent in its presence; posses alternate mechanisms for breaking down peroxides and superoxide.

Capnophiles

Grow best at a high CO2 and a low O2 tension than is normally present on the atmosphere.

Neutrophiles

Organisms that live and grow in habitats between pH 6-8.

Acidophiles

Acid loving organisms pH – below 6-7

Alkalinophiles

Organisms that enjoy elevated pH – higher than 7-8

Osmophiles

Live in habitats with high salute concentrations

Halophiles

Prefer high concentration of Salt.

Obligate halophiles

Require at least 9% NaCl.

Facultative halophiles

Resistant to salt, even though they do not normally reside in high salt environments

Symbiosis

“living together”

Symbionts

Members of a symbiotic relationship

Mutualism

Both partners require other partners’ presence

Commensalism

1 partner benefits , 1 is unaffected

Parasitism

1 partner is benefiting, 1 partner is being harmed

Antagonism

An association between free-living species that arises when members of a community compete

Antibiosis

1 partner makes substance to kill other partner

Synergism

2 organisms work well together and fine when separated

Biofilms

Mixed communities of bacteria and other microbes that are attached to a surface and each other.

Quorum sensing

Used by bacteria to interact with members of the same species as well as members of other species that are close by

Lag phase

Period of adaptation, enlargement, and synthesis

Logarithmic (or log) phase

Growth increases exponentially – will continue as long as cells have adequate nutrients and the environment is favorable

Stationary growth phase

Cells division and cell death rates are equal

Death phase

Cells begin to die at an exponential rate