methods used to count cells

direct microscopic count

direct; physically count cells under a microscope

coulter counter

direct; electronically count cells as they pass through a tiny opening

flow cytometer

direct; counts cells and can distinguish live vs dead

real time PCR/genetic probing

direct; quantifies microorganisms using their genetic material

turbidity

indirect; estimates population based on how cloudy the broth is

more cloudy

more bacteria

less cloudy

less bacteria

viable plate count

direct; counts colonies that grow on agar

all of them but _____ we can analyze without culturing

viable plate count

direct =

actually counting cells

indirect =

estimating the number based on something else