Bacteria can be categorized by their tolerance or use of oxygen. All bacteria belong to one of the four categories in the table below.
Oxygen Use and Tolerance Levels in Bacteria
Type of
Bacteria Relationship to Oxygen
strict aerobe All thrive at atmospheric levels of oxygen (21% O2).
facultative anaerobe All thrive at atmospheric levels of oxygen (21% O2) and in the absence of oxygen. Some can both respire and ferment. Some tolerate atmospheric levels of oxygen, but ferment only.
microaerophile All require some oxygen for metabolism but cannot grow in atmospheric levels of oxygen. Most can thrive only in low levels of oxygen (always < 21% O2, often 10% to 2% O2).
strict anaerobe Most require an oxygen-free environment; some can tolerate very low levels of oxygen (from 8% to < 0.5%).
A candle jar is a piece of equipment in which a candle is burned briefly in a sealed jar to reduce the oxygen level inside the jar. Which bacteria are best grown in environments created by candle jars that reduce the oxygen level by half?
Responses
strict aerobes
strict aerobes
facultative anaerobes
facultative anaerobes
microaerophiles
microaerophiles
strict anaerobes
strict anaerobes
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