Chapter 6: Microbial Growth

The increase in the number of cells is known as:

microbial growth

What are groups of cells large enough to be seen with the naked called?

colonies

What are the physical requirements for microbial growth?

temperature, pH, osmotic pressure

What are the chemical requirements for bacterial growth?

macro/micronutrients, oxygen

Cold-loving microbes

psychrotrophs

Moderate temperature-loving microbes

mesophiles

Heat-loving microbes

thermophiles

The lowest temperature at which a species will grow

minimum growth temperature

The temperature at which a microbe grows best

optimum growth temperature

The highest temperature at which
binary fission is possible

maximum growth temperature

Most bacteria prefer a pH range of:

6.5-7.5

Bacteria that prefer acidic conditions

acidophiles

In what type of solution will cells not swell or shrink?

isotonic

Half the dry weight of a typical bacterial cell is:

carbon

Chemicals or elements required by the microbe in small quantities

trace elements

Bacteria that are unable to use oxygen for ATP
synthesis, harmed by )2

obligate anaerobe

Oganisms that require oxygen to live and to
synthesize ATP, cannot grow without O2

obligate aerobe

Can use oxygen if present but can continue to live and grow when oxygen is NOT present

facultative anaerobe

Do not require oxygen to grow but can tolerate it well, oxygen gas is NOT toxic to these organisms

aerotolerant anaerobe

Aerobic (require oxygen) but only grow in oxygen concentrations lower than those in air

microaerophiles

A nutrient material prepared for the growth of
microorganisms

culture medium

Microbes that are introduced into a culture media to initiate growth

inoculum

Microbes that grow and multiply in or on a culture medium

culture

Contain only one species seen on a solid
agar plate

pure culture

A population of cells from a single cell or from a
group of attached cells, made of clones

colony

A visible population of viruses that have destroyed host cells form a:

viral plaque

A unit of measurement used in virology to quantify the number of infectious virus particles in a sample

plaque forming unti

A unit of measurement that estimates the number of bacteria cells in a sample that can multiply to form a visible colony on a culture plate

colony forming unit

Culture media where the exact chemical composition is known

chemically defined media

“Picky eaters” that require many growth factors

fastidious bacteria

Culture media where he exact chemical
composition varies from batch to batch

complex media

Culture media that removes All available O2 for the growth of anerobic bacteria

reducing media

Culture media that suppress unwanted microbes and encourages growth of desired microbes

selective media

Culture media that allow differentiation between bacteria within a group

differential media

A non-selective culture medium that encourages the growth of a desired microbe
by increasing very small numbers of a
desired organism to detectable levels

enrichment media

The time required for a cell to divide, typically through binary fission

generation time

The period of little to no cell division

lag phase

The period when cells begin to divide,
cellular reproduction is at its highest

log phase

The period of equilibrium, the number of cell death is equal to the number of
new cells being produced

stationary phase

The max number of organisms an environment can support

carrying capacity

The period where the number of deaths occurring exceed the number of microbes being formed

death phase

The death phase in the bacterial growth curve is also known as the

logarithmic decline phase

The log phase in the bacterial growth curve is also known as the

exponential growth phase

A measurement of cloudiness within a
spectrophotometer

turbidity