Chapter Review on Cell Density and Growth Rates

These flashcards cover key concepts from the chapters on cell density, growth rates, and related methodologies.

What chapters will be covered in exam two?

Chapters four and five, focusing only on material since the last exam.

What type of calculator is required for the exam?

A calculator capable of performing logarithmic calculations, which is not a phone or iPad.

How do you calculate the original density of cells from colony counts?

Take the number of CFUs divided by the dilution factor and the plating volume.

What is a colony forming unit (CFU)?

A CFU represents a single cell that can form a colony on agar plates.

What is the importance of measuring cell density?

It helps in estimating the concentration of microorganisms in a culture.

What unit is commonly used to express cell density?

Cells per milliliter (cells/mL).

What kind of microscope slide is used to count cells directly?

A Petroff-Hausser chamber.

How many milliliters are equivalent to one cubic centimeter (cc)?

One cubic centimeter is equal to one milliliter.

What does turbidity indicate in a microbial culture?

Turbidity is proportional to the amount of microorganisms present in the solution.

What is a flow cytometer used for?

To measure the flow of cells in a single file and analyze their size and fluorescence.

What environmental factors can affect microbial growth rates?

Physical, chemical, and biological parameters.

What is the purpose of a fluorescence activated cell sorter (FACS)?

To selectively isolate specific cell populations based on their fluorescence characteristics.

Why do some bacteria prefer low oxygen environments?

They may be microaerophilic, requiring oxygen but at lower concentrations.

What kind of cells does a hemocytometer count?

It typically counts white and red blood cells.

What is the average acceptable colony count on plates for calculations?

Between 30 and 300 colonies.

What happens to oxygen levels in deeper waters?

Oxygen becomes depleted due to consumption by microbial activity.

How does cell size affect light scattering in flow cytometry?

Larger cells scatter more light, allowing for size differentiation during analysis.