Chap 6-Bacterial Growth and Nutrition

Isolation streaking

Separation of colonies into pure cultures (single species)

General purpose medium

Nutrient agar, grows most non-fastidious bacteria

Defined medium

Components are known precisely

Complex medium

Exact composition is unknown

Selective media

Prevent some types of bacteria from growing, favoring the growth of one specific type

Differential media

Species grow equally, difference distinguished by a color indicator

Heterotrophs

Obtain carbon compounds from other organisms (pathogens)

Autotrophs

Make their own carbon compounds starting with CO2

Lithotrophs

Use inorganic chemical compounds as an energy source (little to no carbon)

Nitrifying/nitrate-reducing bacteria

Converts NH3 into Nitrate or Nitrite

Thermophiles

Grow at very high temperatures

Barophiles

Grow at very high pressures, located in the ocean

Psychrophiles

Grow at very cold temperatures

Mesophiles

Growth range between 68-104F (middle-ground environment), most pathogens are mesophiles

Halophiles

Grow in environments with high concentrations of salt

Obligate Aerobes

Require oxygen for growth

Obligate Anaerobes

Do not require oxygen for growth

Facultative Anaerobes

Aerobic and anaerobic, survive with or without oxygen

Biofilms

Mass of bacteria that stick to and multiply on a solid surface, resistant to destruction

What are bacteria in endospore form like?

They are dormant and require no nutrition or energy

Live bacteria cells

Vegetative (non-spore) state, able to reproduce