300px|Aerobic and anaerobic bacteria
_1:_[[Obligate_aerobe.html" style="text-decoration: none;"class="mw-redirect" title="thioglycolate broth">bacteria can be identified by growing them in test tubes of [[thioglycolate broth:
1: [[Obligate aerobe">thioglycolate broth">bacteria can be identified by growing them in test tubes of [[thioglycolate broth:
1: [[Obligate aerobes need oxygen because they cannot ferment or respire anaerobically. They gather at the top of the tube where the oxygen concentration is highest.
2: [[Obligate anaerobes are poisoned by oxygen, so they gather at the bottom of the tube where the oxygen concentration is lowest.
3: Facultative anaerobes can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more ATP than fermentation.
s need oxygen because they cannot ferment or respire anaerobically. However, they are poisoned by high concentrations of oxygen. They gather in the upper part of the test tube but not the very top.
5: Aerotolerant anaerobe
s do not require oxygen as they use fermentation to make ATP. Unlike obligate anaerobes, they are not poisoned by oxygen. They can be found evenly spread throughout the test tube.
anaerobe is an organism
that makes ATP
by aerobic respiration
is present, but is capable of switching to fermentation
if oxygen is absent.
Some examples of facultatively anaerobic bacteria are ''Staphylococcus
'' and ''Yersinia pestis
''. Certain eukaryote
s are also facultative anaerobes, including fungi
such as ''Saccharomyces cerevisiae
and many aquatic invertebrates
such as nereid polychaete
* Aerobic respiration
* Anaerobic respiration
* Obligate aerobe
* Obligate anaerobe
Facultative Anaerobic Bacteria