Microbial Growth Review: Abiotic Factors, Growth Phases, and Measurement (Fill-in-the-Blank)

A set of fill-in-the-blank flashcards covering key concepts from the lecture on abiotic factors, microbial growth and measurement, and biofilm-related topics.

The four abiotic factors discussed are temperature, pH, salt (osmolarity), and __.

oxygen

Osmosis: In a hypertonic environment, water will out of the cell.

leave the cell

Halo-tolerant bacteria are able to grow in higher salt concentrations; many are found on human .

skin

Aquaporins are channels that allow water to across membranes.

diffuse

Mechanosensitive channels open to release solutes in response to changes in pressure.

turgor pressure

Bacteria synthesize (also called compatible solutes) to balance osmotic pressure.

osmoprotectants

Nonhalophiles usually wanna keep salt , while halophiles accumulate solutes in their cytoplasm.

out

CFU stands for __.

colony forming units

The plate count method requires making dilutions to obtain countable colonies.

serial

A hemocytometer provides a -cell count that includes both live and dead cells.

direct

CytoNine stains cells, giving total cell count.

all

Propidium iodide stains only cells.

dead

Absorbance is inversely related to light ; higher absorbance means more growth.

transmittance

The biofilm matrix is composed of extracellular substances.

polymeric

Autoinducers trigger gene expression changes when a population reaches a critical density; one example is .

AHL

In the Hawaiian bobtail squid mutualism, bacterial autoinducers trigger bioluminescence that provides the squid with .

camouflage

The exponential growth equation is Nt = N0 × 2^n; n is the number of .

generations

Generation time is the time it takes for a population to double, going from one cell to cells.

two

Listeria monocytogenes grows by rather than binary fission.

budding

Streptomyces form hyphae that bear spores.

aerial

Eukaryotic microbes reproduce asexually via (mitosis) and may also reproduce sexually via gamete fusion.

mitosis

In the long-term stationary phase, bacteria can exhibit a phenotype.

persistence

Biofilms confer enhanced resistance to and environmental stresses.

antibiotics

During the log phase, cells undergo exponential .

growth

Late log phase triggers production of secondary metabolites such as .

antibiotics

One colony on a plate is assumed to arise from a single .

cell