Why are some xenobiotics biodegraded slower than crude oil and petroleum products?
A) Xenobiotics were designed to inhibit microbial growth.
B) Some xenobiotics are novel compounds that differ from naturally occurring chemicals, thus microorganisms have not yet evolved to effectively degrade them.
C) Only cometabolic microbial processes degrade xenobiotics.
D) Chlorinated compounds are so toxic that biodegradation is not possible.
The production of ________ by ________ is thought to be a major contributor to the biodeterioration of stone building materials.
A) oxalic acid / fungi
B) sulfuric acid / sulfate reducers
C) nitric acid / nitrate reducers
D) carbonic acid / lichens
To prevent the souring of crude oil, ________ is added to oil well injection water to encourage ________ instead of ________.
A) oxygen / aerobic respiration / sulfate reduction
B) sulfate / sulfate reduction / fermentation
C) sulfate / sulfate reduction / nitrate reduction
D) nitrate / nitrate reduction / sulfate reduction
Which group of organisms is thought to be responsible for the corrosion of submerged metal structures and oil pipelines?
A) fermentative microorganisms
B) acidophilic iron-oxidizers
C) sulfate reducers
D) hydrocarbon-degrading anaerobes
Reductive dechlorination is a process in which
A) the number of chlorine atoms present is reduced by oxygenase enzymes.
B) chlorinated organics are used as terminal electron acceptors in anaerobic respiration.
C) carbon dioxide is the final end product.
D) xenobiotics are cometabolized with other reductive reactions.
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