Video Transcript
What is a defining feature of an
inorganic molecule found in a living organism? (A) It does not contain any
carbon–hydrogen bonds. (B) It is excreted as waste. (C) It contains chloride atoms. Or (D) it cannot be broken down
into smaller subunits.
So what is an inorganic
molecule? Inorganic molecules are around us
all of the time. Sodium chloride, with the molecular
formula NaCl, is an inorganic molecule more commonly known as table salt. Water is the inorganic molecule
that makes up around 60 percent of the human body. Oxygen is the inorganic molecule
that we breathe to sustain life. This question asks for a defining
feature of an inorganic molecule.
In order to answer this question,
we need to clarify the difference between organic and inorganic molecules. Organic molecules are those that
contain carbon and hydrogen atoms joined together. On the other hand, inorganic
molecules do not contain carbon–hydrogen bonds.
Answer (B) states that inorganic
molecules are excreted as waste. But this can also be true of
organic molecules. For instance, uric acid, which
happens to be an organic molecule containing carbon–hydrogen bonds, is a waste
product that is excreted in the urine. Therefore, excretion is not a
defining feature of inorganic molecules alone.
Answer (C) is incorrect in two
ways. Firstly, chloride is not an atom
but is the ionic form of chlorine atoms. Secondly, while it can be true that
inorganic molecules contain chloride, there are many inorganic compounds that do not
contain chloride. As we already know, water and
oxygen are inorganic molecules and neither contain chloride.
Finally, answer (D) states that
inorganic molecules cannot be broken down into smaller subunits. This is not necessarily true. Inorganic molecules that are
compounds can be broken down into smaller units. For instance, water can be broken
down into its component parts, hydrogen and oxygen.
Therefore, the defining feature of
an inorganic molecule is (A). It does not contain any
carbon–hydrogen bonds.
