Question

40) 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.

Answer 1

Some xenobiotics are degraded more slowly than crude oil because they are synthetic and differ from natural compounds, posing a challenge for microbial degradation due to the lack of evolved metabolic pathways.

Step-by-step explanation:

The reason some xenobiotics are biodegraded slower than crude oil and petroleum products is primarily because xenobiotics are novel synthetic compounds that do not occur naturally in the environment. Microorganisms have not had the chance to evolve the metabolic pathways necessary to effectively degrade these compounds. Therefore, unlike crude oil and petroleum products which are composed of hydrocarbons similar to those already existing in nature, xenobiotics may resist breakdown due to their unfamiliar structures and chemical properties.