Exam 14: Metabolic Diversity of Microorganisms

Which group of microorganisms would the Calvin cycle LEAST likely be found in?

Reaction centers ONLY indirectly receive photon energy via light-harvesting molecules.

Explain why it is unlikely an iron-oxidizing bacterium would thrive in a cold stream with a neutral pH. Also propose an experiment that would test whether iron-oxidizing bacteria are present in the stream.

Reductive dechlorination involves chlorinated organic compounds serving as electron donors and releasing the chloride in inorganic forms.

Obligate anaerobes can often use ________ electropositive redox couples than facultative anaerobes, and ________ metabolism is most common in this group as well.

Some sulfur-oxidizing bacteria can simultaneously reduce nitrate, which enables them to grow anaerobically.

A researcher lacked the necessary equipment to measure methane production so instead monitored CO₂ concentration as an unknown archaeon grew and produced methane. Why might CO₂ NOT decrease while methane would still increase?

Alternative autotrophic routes to the Calvin cycle such as the reverse citric acid cycle and the hydroxypropionate pathway are unified in their requirement for

Because H₂ levels in oxic environments are transient, it is likely that aerobic hydrogen bacteria shift between chemoorganotrophy and chemolithotrophy depending on levels of organic compounds and hydrogen in their habitats.

Some purple bacteria harvest light using bacteriochlorophylls.

The path of electron flow in oxygenic phototrophs is referred to as the ________ scheme.

What metabolism would be favored when there is a lack of electron acceptors?

Chlorosomes are present in purple bacteria but absent in green sulfur and green nonsulfur bacteria.

Why does an organism that is able to respire both aerobically and anaerobically preferentially undergo aerobic respiration?

The Calvin cycle provides autotrophs the ability to convert inorganic carbon into biomass and generate energy during this process.

What would likely occur if an anammox bacterium was unable to use ladderane lipids?

The process by which electrons from the quinone pool are forced against the thermodynamic gradient to reduce NAD⁺ to NADH is called reverse

The serine pathway and ribulose monophosphate pathway can both be used by ________ as a way to incorporate carbon into biomass.

One result of the oxidation of reduced sulfur compounds is a rise in the pH of the medium.

Fermentation of organic compounds can produce acetate.