Chapter 6: Microbial Growth

Microbes

________ that grow better at high CO2 concentra- tions are called capnophiles.

nutrient material

A(n) ________ prepared for the growth of microorganisms in a laboratory is called a culture medium.

Microaerophiles

________ are aerobic and require oxygen.

direct microscopic

In the method known as the ________ count, a mea- sured volume of a bacterial suspension is placed within a defined area on a microscope slide.

exact chemical composition

A chemically defined medium is one whose ________ is known.

visible colony

A(n) ________ theoretically arises from a single spore or vegetative cell or from a group of the same microorganisms attached to one another in clumps or chains.

Differential media

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

binary fission

Bacteria normally reproduce by ________.

Deep freezing

________ is a process in which a pure culture of microbes is placed in a suspending liquid and quick- frozen at temper- atures ranging from- 50°C to- 95°C.

Anaerobes

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

Organisms

________ that require oxygen to live are called obligate aerobes.

Aerotolerant anaerobes

________ are fermentative and can not use oxygen for growth, but they tolerate it fairly well.

freeze drying

During lyophilization (________), a suspension of microbes is quickly frozen at temperatures ranging from- 54°C to- 72°C, and the water is removed by a high vacuum (sublimation)

pure cultures

The isolation method most commonly used to get ________ is the streak plate method.

Essential organic compounds an organism

________ is unable to synthe- size are known as organic growth factors; they must be directly obtained from the environment.

Exponential growth stops

________ because the bacteria approach the carrying capacity, the number of organisms that an environment can support.

Microbes

________ require very small amounts of other mineral ele- ments, such as iron, copper, molybdenum, and zinc; these are referred to as trace elements.

Microbes

________ that are introduced into a culture medium to initiate growth are called an inoculum.

microbes

The ________ that grow and multiply in or on a culture medium are referred to as a culture.