Exam 5: Microbial Growth

An organism that can grow at 0°C but whose optimum temperature is 20- 40°C is considered ___________. These organisms are ___________(more/less) widely distributed in nature than organisms that grow exclusively at cold temperatures.

Because two or more cells may clump together, instead of reporting "viable cell count" microbiologists often use the term___________.

The process by which two cells arise from one is known as

The death phase applies to individual cells rather than populations.

Factors affecting an organism's minimal growth temperature are not entirely understood.

The rates of exponential growth (in the exponential phase) vary greatly.

A microbe growing in a refrigerator is likely a

Explain why a hyperthermophile is unlikely to be a human pathogen.

Based on studies with obligate acidophiles, high concentrations of hydrogen ions are required for membrane stability.

Why are microbial doubling times in nature typically longer than those obtained in the laboratory?

One problem with batch cultures is the change in the chemical composition of the medium as growth progresses.

For most physiological experiments, it is desirable for cells to be in the

Serial dilutions are generally made

The most common type of continuous culture device is called a(n)___________ .

An alkaliphile would likely be found in soda lakes and high carbonate soils.

Explain our present understanding of molecular adaptations to the cytoplasmic membrane that are present in thermophiles.

Formation of the divisome begins with the attachment of which protein in a ring around the center of the cell?

Explain our present understanding of molecular adaptations to the cytoplasmic membrane that are present in psychrophiles.

Under what conditions would a lag phase NOT occur?

The ratio of the vapor pressure of the air in equilibrium with a substance to the vapor pressure of pure water is known as